#139 - Mime multipart request parsing.

src/Microsoft.AspNet.Http.Extensions/project.json

@@ -8,7 +8,7 @@
     "frameworks" : {
         "aspnet50" : {
         },
-        "aspnetcore50" : { 
+        "aspnetcore50" : {
             "dependencies": {
                 "System.Reflection.TypeExtensions": "4.0.0-beta-*",
                 "System.Runtime": "4.0.20-beta-*"

src/Microsoft.AspNet.Http/FragmentString.cs

@@ -90,12 +90,8 @@ namespace Microsoft.AspNet.Http
         /// </summary>
         /// <param name="uri">The Uri object</param>
         /// <returns>The resulting FragmentString</returns>
-        public static FragmentString FromUriComponent(Uri uri)
+        public static FragmentString FromUriComponent([NotNull] Uri uri)
         {
-            if (uri == null)
-            {
-                throw new ArgumentNullException("uri");
-            }
             string fragmentValue = uri.GetComponents(UriComponents.Fragment, UriFormat.UriEscaped);
             if (!string.IsNullOrEmpty(fragmentValue))
             {

src/Microsoft.AspNet.Http/HostString.cs

@@ -134,12 +134,8 @@ namespace Microsoft.AspNet.Http
         /// </summary>
         /// <param name="uri"></param>
         /// <returns></returns>
-        public static HostString FromUriComponent(Uri uri)
+        public static HostString FromUriComponent([NotNull] Uri uri)
         {
-            if (uri == null)
-            {
-                throw new ArgumentNullException("uri");
-            }
             return new HostString(uri.GetComponents(
                 UriComponents.NormalizedHost | // Always convert punycode to Unicode.
                 UriComponents.HostAndPort, UriFormat.Unescaped));

src/Microsoft.AspNet.Http/HttpRequest.cs

@@ -64,12 +64,6 @@ namespace Microsoft.AspNet.Http
         /// <returns>The query value collection parsed from owin.RequestQueryString.</returns>
         public abstract IReadableStringCollection Query { get; }
 
-        /// <summary>
-        /// Gets the form collection.
-        /// </summary>
-        /// <returns>The form collection parsed from the request body.</returns>
-        public abstract Task<IReadableStringCollection> GetFormAsync(CancellationToken cancellationToken = default(CancellationToken));
-
         /// <summary>
         /// Gets or set the owin.RequestProtocol.
         /// </summary>
@@ -128,5 +122,21 @@ namespace Microsoft.AspNet.Http
         /// </summary>
         /// <returns>The owin.RequestBody Stream.</returns>
         public abstract Stream Body { get; set; }
+
+        /// <summary>
+        /// Checks the content-type header for form types.
+        /// </summary>
+        public abstract bool HasFormContentType { get; }
+
+        /// <summary>
+        /// Gets or sets the request body as a form.
+        /// </summary>
+        public abstract IFormCollection Form { get; set; }
+
+        /// <summary>
+        /// Reads the request body if it is a form.
+        /// </summary>
+        /// <returns></returns>
+        public abstract Task<IFormCollection> ReadFormAsync(CancellationToken cancellationToken = new CancellationToken());
     }
 }

src/Microsoft.AspNet.Http/IFormCollection.cs

@@ -1,6 +1,8 @@
 // Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System.Collections.Generic;
+
 namespace Microsoft.AspNet.Http
 {
     /// <summary>
@@ -8,5 +10,6 @@ namespace Microsoft.AspNet.Http
     /// </summary>
     public interface IFormCollection : IReadableStringCollection
     {
+        IFormFileCollection Files { get; }
     }
 }

src/Microsoft.AspNet.Http/IFormFile.cs

@@ -0,0 +1,20 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.IO;
+
+namespace Microsoft.AspNet.Http
+{
+    public interface IFormFile
+    {
+        string ContentType { get; }
+
+        string ContentDisposition { get; }
+
+        IHeaderDictionary Headers { get; }
+
+        long Length { get; }
+
+        Stream OpenReadStream();
+    }
+}

src/Microsoft.AspNet.Http/IFormFileCollection.cs

@@ -0,0 +1,16 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+
+namespace Microsoft.AspNet.Http
+{
+    public interface IFormFileCollection : IList<IFormFile>
+    {
+        IFormFile this[string name] { get; }
+
+        IFormFile GetFile(string name);
+
+        IList<IFormFile> GetFiles(string name);
+    }
+}

src/Microsoft.AspNet.Http/PathString.cs

@@ -86,12 +86,8 @@ namespace Microsoft.AspNet.Http
         /// </summary>
         /// <param name="uri">The Uri object</param>
         /// <returns>The resulting PathString</returns>
-        public static PathString FromUriComponent(Uri uri)
+        public static PathString FromUriComponent([NotNull] Uri uri)
         {
-            if (uri == null)
-            {
-                throw new ArgumentNullException("uri");
-            }
             // REVIEW: what is the exactly correct thing to do?
             return new PathString("/" + uri.GetComponents(UriComponents.Path, UriFormat.Unescaped));
         }

src/Microsoft.AspNet.Http/QueryString.cs

@@ -102,12 +102,8 @@ namespace Microsoft.AspNet.Http
         /// </summary>
         /// <param name="uri">The Uri object</param>
         /// <returns>The resulting QueryString</returns>
-        public static QueryString FromUriComponent(Uri uri)
+        public static QueryString FromUriComponent([NotNull] Uri uri)
         {
-            if (uri == null)
-            {
-                throw new ArgumentNullException("uri");
-            }
             string queryValue = uri.GetComponents(UriComponents.Query, UriFormat.UriEscaped);
             if (!string.IsNullOrEmpty(queryValue))
             {

src/Microsoft.AspNet.Http/Security/AuthenticateResult.cs

@@ -18,16 +18,8 @@ namespace Microsoft.AspNet.Http.Security
         /// <param name="identity">Assigned to Identity. May be null.</param>
         /// <param name="properties">Assigned to Properties. Contains extra information carried along with the identity.</param>
         /// <param name="description">Assigned to Description. Contains information describing the authentication provider.</param>
-        public AuthenticationResult(IIdentity identity, AuthenticationProperties properties, AuthenticationDescription description)
+        public AuthenticationResult(IIdentity identity, [NotNull] AuthenticationProperties properties, [NotNull] AuthenticationDescription description)
         {
-            if (properties == null)
-            {
-                throw new ArgumentNullException("properties");
-            }
-            if (description == null)
-            {
-                throw new ArgumentNullException("description");
-            }
             if (identity != null)
             {
                 Identity = identity as ClaimsIdentity ?? new ClaimsIdentity(identity);

src/Microsoft.AspNet.Http/Security/AuthenticationDescription.cs

@@ -27,12 +27,8 @@ namespace Microsoft.AspNet.Http.Security
         /// Initializes a new instance of the <see cref="AuthenticationDescription"/> class
         /// </summary>
         /// <param name="properties"></param>
-        public AuthenticationDescription(IDictionary<string, object> properties)
+        public AuthenticationDescription([NotNull] IDictionary<string, object> properties)
         {
-            if (properties == null)
-            {
-                throw new ArgumentNullException("properties");
-            }
             Dictionary = properties;
         }
 

src/Microsoft.AspNet.Owin/NotNullAttribute.cs

@@ -0,0 +1,12 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+
+namespace Microsoft.AspNet.Owin
+{
+    [AttributeUsage(AttributeTargets.Parameter, AllowMultiple = false)]
+    internal sealed class NotNullAttribute : Attribute
+    {
+    }
+}

src/Microsoft.AspNet.Owin/OwinFeatureCollection.cs

@@ -399,12 +399,8 @@ namespace Microsoft.AspNet.Owin
             return TryGetValue(item.Key, out result) && result.Equals(item.Value);
         }
 
-        public void CopyTo(KeyValuePair<Type, object>[] array, int arrayIndex)
+        public void CopyTo([NotNull] KeyValuePair<Type, object>[] array, int arrayIndex)
         {
-            if (array == null)
-            {
-                throw new ArgumentNullException("array");
-            }
             if (arrayIndex < 0 || arrayIndex > array.Length)
             {
                 throw new ArgumentOutOfRangeException("arrayIndex", arrayIndex, string.Empty);

src/Microsoft.AspNet.Owin/WebSockets/WebSocketAdapter.cs

@@ -113,7 +113,7 @@ namespace Microsoft.AspNet.Owin
             }
             else
             {
-                throw new ArgumentOutOfRangeException("buffer");
+                throw new ArgumentOutOfRangeException(nameof(buffer));
             }
         }
 
@@ -149,7 +149,7 @@ namespace Microsoft.AspNet.Owin
                 case 0x8:
                     return WebSocketMessageType.Close;
                 default:
-                    throw new ArgumentOutOfRangeException("messageType", messageType, string.Empty);
+                    throw new ArgumentOutOfRangeException(nameof(messageType), messageType, string.Empty);
             }
         }
 
@@ -164,7 +164,7 @@ namespace Microsoft.AspNet.Owin
                 case WebSocketMessageType.Close:
                     return 0x8;
                 default:
-                    throw new ArgumentOutOfRangeException("webSocketMessageType", webSocketMessageType, string.Empty);
+                    throw new ArgumentOutOfRangeException(nameof(webSocketMessageType), webSocketMessageType, string.Empty);
             }
         }
     }

src/Microsoft.AspNet.PipelineCore/BufferingHelper.cs

@@ -0,0 +1,47 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.IO;
+using Microsoft.AspNet.Http;
+using Microsoft.AspNet.WebUtilities;
+
+namespace Microsoft.AspNet.PipelineCore
+{
+    public static class BufferingHelper
+    {
+        internal const int DefaultBufferThreshold = 1024 * 30;
+
+        public static string TempDirectory
+        {
+            get
+            {
+                var temp = Environment.GetEnvironmentVariable("ASPNET_TEMP");
+                if (string.IsNullOrEmpty(temp))
+                {
+                    temp = Environment.GetEnvironmentVariable("TEMP");
+                }
+
+                if (!Directory.Exists(temp))
+                {
+                    // TODO: ???
+                    throw new DirectoryNotFoundException(temp);
+                }
+
+                return temp;
+            }
+        }
+
+        public static HttpRequest EnableRewind([NotNull] this HttpRequest request, int bufferThreshold = DefaultBufferThreshold)
+        {
+            var body = request.Body;
+            if (!body.CanSeek)
+            {
+                // TODO: Register this buffer for disposal at the end of the request to ensure the temp file is deleted.
+                //  Otherwise it won't get deleted until GC closes the stream.
+                request.Body = new FileBufferingReadStream(body, bufferThreshold, TempDirectory);
+            }
+            return request;
+        }
+    }
+}

src/Microsoft.AspNet.PipelineCore/Collections/FormCollection.cs

@@ -1,23 +1,27 @@
 // Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using Microsoft.AspNet.Http;
 using System.Collections.Generic;
+using Microsoft.AspNet.Http;
 
-namespace Microsoft.AspNet.WebUtilities.Collections
+namespace Microsoft.AspNet.PipelineCore.Collections
 {
     /// <summary>
     /// Contains the parsed form values.
     /// </summary>
     public class FormCollection : ReadableStringCollection, IFormCollection
     {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="T:Microsoft.AspNet.WebUtilities.FormCollection" /> class.
-        /// </summary>
-        /// <param name="store">The store for the form.</param>
-        public FormCollection(IDictionary<string, string[]> store)
-            : base(store)
+        public FormCollection([NotNull] IDictionary<string, string[]> store)
+            : this(store, new FormFileCollection())
         {
         }
+
+        public FormCollection([NotNull] IDictionary<string, string[]> store, [NotNull] IFormFileCollection files)
+            : base(store)
+        {
+            Files = files;
+        }
+
+        public IFormFileCollection Files { get; private set; }
     }
 }

src/Microsoft.AspNet.PipelineCore/Collections/FormFileCollection.cs

@@ -0,0 +1,36 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using Microsoft.AspNet.Http;
+
+namespace Microsoft.AspNet.PipelineCore.Collections
+{
+    public class FormFileCollection : List<IFormFile>, IFormFileCollection
+    {
+        public IFormFile this[string name]
+        {
+            get { return GetFile(name); }
+        }
+
+        public IFormFile GetFile(string name)
+        {
+            return Find(file => string.Equals(name, GetName(file.ContentDisposition)));
+        }
+
+        public IList<IFormFile> GetFiles(string name)
+        {
+            return FindAll(file => string.Equals(name, GetName(file.ContentDisposition)));
+        }
+
+        private static string GetName(string contentDisposition)
+        {
+            // TODO: Strongly typed headers will take care of this
+            // Content-Disposition: form-data; name="myfile1"; filename="Misc 002.jpg"
+            var offset = contentDisposition.IndexOf("name=\"") + "name=\"".Length;
+            var key = contentDisposition.Substring(offset, contentDisposition.IndexOf("\"", offset) - offset); // Remove quotes
+            return key;
+        }
+    }
+}

src/Microsoft.AspNet.PipelineCore/Collections/HeaderDictionary.cs

@@ -20,13 +20,8 @@ namespace Microsoft.AspNet.PipelineCore.Collections
         /// Initializes a new instance of the <see cref="T:Microsoft.Owin.HeaderDictionary" /> class.
         /// </summary>
         /// <param name="store">The underlying data store.</param>
-        public HeaderDictionary(IDictionary<string, string[]> store)
+        public HeaderDictionary([NotNull] IDictionary<string, string[]> store)
         {
-            if (store == null)
-            {
-                throw new ArgumentNullException("store");
-            }
-
             Store = store;
         }
 

src/Microsoft.AspNet.PipelineCore/Collections/ItemsDictionary.cs

@@ -3,7 +3,6 @@
 
 using System.Collections;
 using System.Collections.Generic;
-using Microsoft.AspNet.Http;
 
 namespace Microsoft.AspNet.PipelineCore
 {

src/Microsoft.AspNet.PipelineCore/Collections/ReadableStringCollection.cs

@@ -6,7 +6,7 @@ using System.Collections;
 using System.Collections.Generic;
 using Microsoft.AspNet.Http;
 
-namespace Microsoft.AspNet.WebUtilities.Collections
+namespace Microsoft.AspNet.PipelineCore.Collections
 {
     /// <summary>
     /// Accessors for query, forms, etc.
@@ -17,13 +17,8 @@ namespace Microsoft.AspNet.WebUtilities.Collections
         /// Create a new wrapper
         /// </summary>
         /// <param name="store"></param>
-        public ReadableStringCollection(IDictionary<string, string[]> store)
+        public ReadableStringCollection([NotNull] IDictionary<string, string[]> store)
         {
-            if (store == null)
-            {
-                throw new ArgumentNullException("store");
-            }
-
             Store = store;
         }
 
@@ -75,7 +70,7 @@ namespace Microsoft.AspNet.WebUtilities.Collections
         /// <returns></returns>
         public string Get(string key)
         {
-            return ParsingHelpers.GetJoinedValue(Store, key);
+            return GetJoinedValue(Store, key);
         }
 
         /// <summary>
@@ -108,5 +103,15 @@ namespace Microsoft.AspNet.WebUtilities.Collections
         {
             return GetEnumerator();
         }
+
+        private static string GetJoinedValue(IDictionary<string, string[]> store, string key)
+        {
+            string[] values;
+            if (store.TryGetValue(key, out values))
+            {
+                return string.Join(",", values);
+            }
+            return null;
+        }
     }
 }

src/Microsoft.AspNet.PipelineCore/Collections/ResponseCookies.cs

@@ -19,13 +19,8 @@ namespace Microsoft.AspNet.PipelineCore.Collections
         /// Create a new wrapper
         /// </summary>
         /// <param name="headers"></param>
-        public ResponseCookies(IHeaderDictionary headers)
+        public ResponseCookies([NotNull] IHeaderDictionary headers)
         {
-            if (headers == null)
-            {
-                throw new ArgumentNullException("headers");
-            }
-
             Headers = headers;
         }
 
@@ -47,13 +42,8 @@ namespace Microsoft.AspNet.PipelineCore.Collections
         /// <param name="key"></param>
         /// <param name="value"></param>
         /// <param name="options"></param>
-        public void Append(string key, string value, CookieOptions options)
+        public void Append(string key, string value, [NotNull] CookieOptions options)
         {
-            if (options == null)
-            {
-                throw new ArgumentNullException("options");
-            }
-
             bool domainHasValue = !string.IsNullOrEmpty(options.Domain);
             bool pathHasValue = !string.IsNullOrEmpty(options.Path);
             bool expiresHasValue = options.Expires.HasValue;
@@ -98,13 +88,8 @@ namespace Microsoft.AspNet.PipelineCore.Collections
         /// </summary>
         /// <param name="key"></param>
         /// <param name="options"></param>
-        public void Delete(string key, CookieOptions options)
+        public void Delete(string key, [NotNull] CookieOptions options)
         {
-            if (options == null)
-            {
-                throw new ArgumentNullException("options");
-            }
-
             bool domainHasValue = !string.IsNullOrEmpty(options.Domain);
             bool pathHasValue = !string.IsNullOrEmpty(options.Path);
 

src/Microsoft.AspNet.PipelineCore/DefaultHttpContext.cs

@@ -214,12 +214,8 @@ namespace Microsoft.AspNet.PipelineCore
             return authTypeContext.Results;
         }
 
-        public override IEnumerable<AuthenticationResult> Authenticate(IEnumerable<string> authenticationTypes)
+        public override IEnumerable<AuthenticationResult> Authenticate([NotNull] IEnumerable<string> authenticationTypes)
         {
-            if (authenticationTypes == null)
-            {
-                throw new ArgumentNullException();
-            }
             var handler = HttpAuthenticationFeature.Handler;
 
             var authenticateContext = new AuthenticateContext(authenticationTypes);
@@ -238,12 +234,8 @@ namespace Microsoft.AspNet.PipelineCore
             return authenticateContext.Results;
         }
 
-        public override async Task<IEnumerable<AuthenticationResult>> AuthenticateAsync(IEnumerable<string> authenticationTypes)
+        public override async Task<IEnumerable<AuthenticationResult>> AuthenticateAsync([NotNull] IEnumerable<string> authenticationTypes)
         {
-            if (authenticationTypes == null)
-            {
-                throw new ArgumentNullException();
-            }
             var handler = HttpAuthenticationFeature.Handler;
 
             var authenticateContext = new AuthenticateContext(authenticationTypes);

src/Microsoft.AspNet.PipelineCore/DefaultHttpRequest.cs

@@ -2,13 +2,12 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Globalization;
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
+using Microsoft.AspNet.FeatureModel;
 using Microsoft.AspNet.Http;
 using Microsoft.AspNet.Http.Infrastructure;
-using Microsoft.AspNet.FeatureModel;
 using Microsoft.AspNet.HttpFeature;
 using Microsoft.AspNet.PipelineCore.Collections;
 using Microsoft.AspNet.PipelineCore.Infrastructure;
@@ -55,7 +54,7 @@ namespace Microsoft.AspNet.PipelineCore
 
         private IFormFeature FormFeature
         {
-            get { return _form.Fetch(_features) ?? _form.Update(_features, new FormFeature(_features)); }
+            get { return _form.Fetch(_features) ?? _form.Update(_features, new FormFeature(this)); }
         }
 
         private IRequestCookiesFeature RequestCookiesFeature
@@ -83,7 +82,7 @@ namespace Microsoft.AspNet.PipelineCore
             set { HttpRequestFeature.QueryString = value.Value; }
         }
 
-        public override long? ContentLength 
+        public override long? ContentLength
         {
             get
             {
@@ -129,11 +128,6 @@ namespace Microsoft.AspNet.PipelineCore
             get { return QueryFeature.Query; }
         }
 
-        public override Task<IReadableStringCollection> GetFormAsync(CancellationToken cancellationToken = default(CancellationToken))
-        {
-            return FormFeature.GetFormAsync(cancellationToken);
-        }
-
         public override string Protocol
         {
             get { return HttpRequestFeature.Protocol; }
@@ -167,5 +161,21 @@ namespace Microsoft.AspNet.PipelineCore
             get { return Headers[Constants.Headers.AcceptCharset]; }
             set { Headers[Constants.Headers.AcceptCharset] = value; }
         }
+
+        public override bool HasFormContentType
+        {
+            get { return FormFeature.HasFormContentType; }
+        }
+
+        public override IFormCollection Form
+        {
+            get { return FormFeature.ReadForm(); }
+            set { FormFeature.Form = value; }
+        }
+
+        public override Task<IFormCollection> ReadFormAsync(CancellationToken cancellationToken)
+        {
+            return FormFeature.ReadFormAsync(cancellationToken);
+        }
     }
 }

src/Microsoft.AspNet.PipelineCore/DefaultHttpResponse.cs

@@ -129,12 +129,8 @@ namespace Microsoft.AspNet.PipelineCore
             Headers.Set(Constants.Headers.Location, location);
         }
 
-        public override void Challenge(AuthenticationProperties properties, IEnumerable<string> authenticationTypes)
+        public override void Challenge(AuthenticationProperties properties, [NotNull] IEnumerable<string> authenticationTypes)
         {
-            if (authenticationTypes == null)
-            {
-                throw new ArgumentNullException();
-            }
             HttpResponseFeature.StatusCode = 401;
             var handler = HttpAuthenticationFeature.Handler;
 
@@ -152,13 +148,8 @@ namespace Microsoft.AspNet.PipelineCore
             }
         }
 
-        public override void SignIn(AuthenticationProperties properties, IEnumerable<ClaimsIdentity> identities)
+        public override void SignIn(AuthenticationProperties properties, [NotNull] IEnumerable<ClaimsIdentity> identities)
         {
-            if (identities == null)
-            {
-                throw new ArgumentNullException();
-            }
-
             var handler = HttpAuthenticationFeature.Handler;
 
             var signInContext = new SignInContext(identities, properties == null ? null : properties.Dictionary);
@@ -175,12 +166,8 @@ namespace Microsoft.AspNet.PipelineCore
             }
         }
 
-        public override void SignOut(IEnumerable<string> authenticationTypes)
+        public override void SignOut([NotNull] IEnumerable<string> authenticationTypes)
         {
-            if (authenticationTypes == null)
-            {
-                throw new ArgumentNullException();
-            }
             var handler = HttpAuthenticationFeature.Handler;
 
             var signOutContext = new SignOutContext(authenticationTypes);

src/Microsoft.AspNet.PipelineCore/FormFeature.cs

@@ -1,71 +1,192 @@
 // Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.AspNet.FeatureModel;
 using Microsoft.AspNet.Http;
-using Microsoft.AspNet.HttpFeature;
-using Microsoft.AspNet.PipelineCore.Infrastructure;
+using Microsoft.AspNet.PipelineCore.Collections;
 using Microsoft.AspNet.WebUtilities;
-using Microsoft.AspNet.WebUtilities.Collections;
 
 namespace Microsoft.AspNet.PipelineCore
 {
     public class FormFeature : IFormFeature
     {
-        private readonly IFeatureCollection _features;
-        private readonly FeatureReference<IHttpRequestFeature> _request = FeatureReference<IHttpRequestFeature>.Default;
-        private Stream _bodyStream;
-        private IReadableStringCollection _form;
+        private readonly HttpRequest _request;
 
-        public FormFeature([NotNull] IDictionary<string, string[]> form)
-            : this (new ReadableStringCollection(form))
+        public FormFeature([NotNull] IFormCollection form)
         {
+            Form = form;
         }
 
-        public FormFeature([NotNull] IReadableStringCollection form)
+        public FormFeature([NotNull] HttpRequest request)
         {
-            _form = form;
+            _request = request;
         }
 
-        public FormFeature([NotNull] IFeatureCollection features)
+        public bool HasFormContentType
         {
-            _features = features;
-        }
-
-        public async Task<IReadableStringCollection> GetFormAsync(CancellationToken cancellationToken)
-        {
-            if (_features == null)
+            get
             {
-                return _form;
+                // Set directly
+                if (Form != null)
+                {
+                    return true;
+                }
+
+                return HasApplicationFormContentType() || HasMultipartFormContentType();
+            }
+        }
+
+        public IFormCollection Form { get; set; }
+
+        public IFormCollection ReadForm()
+        {
+            if (Form != null)
+            {
+                return Form;
             }
 
-            var body = _request.Fetch(_features).Body;
-
-            if (_bodyStream == null || _bodyStream != body)
+            if (!HasFormContentType)
             {
-                _bodyStream = body;
-                if (!_bodyStream.CanSeek)
+                throw new InvalidOperationException("Incorrect Content-Type: " + _request.ContentType);
+            }
+
+            // TODO: How do we prevent thread exhaustion?
+            return ReadFormAsync(CancellationToken.None).GetAwaiter().GetResult();
+        }
+
+        public async Task<IFormCollection> ReadFormAsync(CancellationToken cancellationToken)
+        {
+            if (Form != null)
+            {
+                return Form;
+            }
+
+            if (!HasFormContentType)
+            {
+                throw new InvalidOperationException("Incorrect Content-Type: " + _request.ContentType);
+            }
+
+            cancellationToken.ThrowIfCancellationRequested();
+
+            _request.EnableRewind();
+
+            IDictionary<string, string[]> formFields = null;
+            var files = new FormFileCollection();
+
+            // Some of these code paths use StreamReader which does not support cancellation tokens.
+            using (cancellationToken.Register(_request.HttpContext.Abort))
+            {
+                // Check the content-type
+                if (HasApplicationFormContentType())
                 {
-                    var buffer = new MemoryStream();
-                    await _bodyStream.CopyToAsync(buffer, 4096, cancellationToken);
-                    _bodyStream = buffer;
-                    _request.Fetch(_features).Body = _bodyStream;
-                    _bodyStream.Seek(0, SeekOrigin.Begin);
+                    // TODO: Read the charset from the content-type header after we get strongly typed headers
+                    formFields = await FormReader.ReadFormAsync(_request.Body, cancellationToken);
                 }
-                using (var streamReader = new StreamReader(_bodyStream, Encoding.UTF8,
-                                                           detectEncodingFromByteOrderMarks: true,
-                                                           bufferSize: 1024, leaveOpen: true))
+                else if (HasMultipartFormContentType())
                 {
-                    string form = await streamReader.ReadToEndAsync();
-                    _form = FormHelpers.ParseForm(form);
+                    var formAccumulator = new KeyValueAccumulator<string, string>(StringComparer.OrdinalIgnoreCase);
+
+                    var boundary = GetBoundary(_request.ContentType);
+                    var multipartReader = new MultipartReader(boundary, _request.Body);
+                    var section = await multipartReader.ReadNextSectionAsync(cancellationToken);
+                    while (section != null)
+                    {
+                        var headers = new HeaderDictionary(section.Headers);
+                        var contentDisposition = headers["Content-Disposition"];
+                        if (HasFileContentDisposition(contentDisposition))
+                        {
+                            // Find the end
+                            await section.Body.DrainAsync(cancellationToken);
+
+                            var file = new FormFile(_request.Body, section.BaseStreamOffset.Value, section.Body.Length)
+                            {
+                                Headers = headers,
+                            };
+                            files.Add(file);
+                        }
+                        else if (HasFormDataContentDisposition(contentDisposition))
+                        {
+                            // Content-Disposition: form-data; name="key"
+                            //
+                            // value
+
+                            // TODO: Strongly typed headers will take care of this
+                            var offset = contentDisposition.IndexOf("name=") + "name=".Length;
+                            var key = contentDisposition.Substring(offset + 1, contentDisposition.Length - offset - 2); // Remove quotes
+
+                            // TODO: Read the charset from the content-disposition header after we get strongly typed headers
+                            using (var reader = new StreamReader(section.Body, Encoding.UTF8, detectEncodingFromByteOrderMarks: true, bufferSize: 1024, leaveOpen: true))
+                            {
+                                var value = await reader.ReadToEndAsync();
+                                formAccumulator.Append(key, value);
+                            }
+                        }
+                        else
+                        {
+                            System.Diagnostics.Debug.Assert(false, "Unrecognized content-disposition for this section: " + contentDisposition);
+                        }
+
+                        section = await multipartReader.ReadNextSectionAsync(cancellationToken);
+                    }
+
+                    formFields = formAccumulator.GetResults();
                 }
             }
-            return _form;
+
+            Form = new FormCollection(formFields, files);
+            return Form;
+        }
+
+        private bool HasApplicationFormContentType()
+        {
+            // TODO: Strongly typed headers will take care of this for us
+            // Content-Type: application/x-www-form-urlencoded; charset=utf-8
+            var contentType = _request.ContentType;
+            return !string.IsNullOrEmpty(contentType) && contentType.IndexOf("application/x-www-form-urlencoded", StringComparison.OrdinalIgnoreCase) >= 0;
+        }
+
+        private bool HasMultipartFormContentType()
+        {
+            // TODO: Strongly typed headers will take care of this for us
+            // Content-Type: multipart/form-data; boundary=----WebKitFormBoundarymx2fSWqWSd0OxQqq
+            var contentType = _request.ContentType;
+            return !string.IsNullOrEmpty(contentType) && contentType.IndexOf("multipart/form-data", StringComparison.OrdinalIgnoreCase) >= 0;
+        }
+
+        private bool HasFormDataContentDisposition(string contentDisposition)
+        {
+            // TODO: Strongly typed headers will take care of this for us
+            // Content-Disposition: form-data; name="key";
+            return !string.IsNullOrEmpty(contentDisposition) && contentDisposition.Contains("form-data") && !contentDisposition.Contains("filename=");
+        }
+
+        private bool HasFileContentDisposition(string contentDisposition)
+        {
+            // TODO: Strongly typed headers will take care of this for us
+            // Content-Disposition: form-data; name="myfile1"; filename="Misc 002.jpg"
+            return !string.IsNullOrEmpty(contentDisposition) && contentDisposition.Contains("form-data") && contentDisposition.Contains("filename=");
+        }
+
+        // Content-Type: multipart/form-data; boundary=----WebKitFormBoundarymx2fSWqWSd0OxQqq
+        private static string GetBoundary(string contentType)
+        {
+            // TODO: Strongly typed headers will take care of this for us
+            // TODO: Limit the length of boundary we accept. The spec says ~70 chars.
+            var elements = contentType.Split(' ');
+            var element = elements.Where(entry => entry.StartsWith("boundary=")).First();
+            var boundary = element.Substring("boundary=".Length);
+            // Remove quotes
+            if (boundary.Length >= 2 && boundary[0] == '"' && boundary[boundary.Length - 1] == '"')
+            {
+                boundary = boundary.Substring(1, boundary.Length - 2);
+            }
+            return boundary;
         }
     }
 }

src/Microsoft.AspNet.PipelineCore/FormFile.cs

@@ -0,0 +1,46 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.IO;
+using Microsoft.AspNet.Http;
+
+namespace Microsoft.AspNet.PipelineCore
+{
+    public class FormFile : IFormFile
+    {
+        private Stream _baseStream;
+        private long _baseStreamOffset;
+        private long _length;
+
+        public FormFile(Stream baseStream, long baseStreamOffset, long length)
+        {
+            _baseStream = baseStream;
+            _baseStreamOffset = baseStreamOffset;
+            _length = length;
+        }
+
+        public string ContentDisposition
+        {
+            get { return Headers["Content-Disposition"]; }
+            set { Headers["Content-Disposition"] = value; }
+        }
+
+        public string ContentType
+        {
+            get { return Headers["Content-Type"]; }
+            set { Headers["Content-Type"] = value; }
+        }
+
+        public IHeaderDictionary Headers { get; set; }
+
+        public long Length
+        {
+            get { return _length; }
+        }
+
+        public Stream OpenReadStream()
+        {
+            return new ReferenceReadStream(_baseStream, _baseStreamOffset, _length);
+        }
+    }
+}

src/Microsoft.AspNet.PipelineCore/IFormFeature.cs

@@ -4,11 +4,33 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNet.Http;
+using Microsoft.Framework.Runtime;
 
 namespace Microsoft.AspNet.PipelineCore
 {
     public interface IFormFeature
     {
-        Task<IReadableStringCollection> GetFormAsync(CancellationToken cancellationToken);
+        /// <summary>
+        /// Indicates if the request has a supported form content-type.
+        /// </summary>
+        bool HasFormContentType { get; }
+
+        /// <summary>
+        /// The parsed form, if any.
+        /// </summary>
+        IFormCollection Form { get; set; }
+
+        /// <summary>
+        /// Parses the request body as a form.
+        /// </summary>
+        /// <returns></returns>
+        IFormCollection ReadForm();
+
+        /// <summary>
+        /// Parses the request body as a form.
+        /// </summary>
+        /// <param name="cancellationToken"></param>
+        /// <returns></returns>
+        Task<IFormCollection> ReadFormAsync(CancellationToken cancellationToken);
     }
 }

src/Microsoft.AspNet.PipelineCore/Infrastructure/ParsingHelpers.cs

@@ -445,12 +445,8 @@ namespace Microsoft.AspNet.PipelineCore.Infrastructure
 
         #endregion
 
-        public bool StartsWith(string text, StringComparison comparisonType)
+        public bool StartsWith([NotNull] string text, StringComparison comparisonType)
         {
-            if (text == null)
-            {
-                throw new ArgumentNullException("text");
-            }
             int textLength = text.Length;
             if (!HasValue || _count < textLength)
             {
@@ -460,12 +456,8 @@ namespace Microsoft.AspNet.PipelineCore.Infrastructure
             return string.Compare(_buffer, _offset, text, 0, textLength, comparisonType) == 0;
         }
 
-        public bool EndsWith(string text, StringComparison comparisonType)
+        public bool EndsWith([NotNull] string text, StringComparison comparisonType)
         {
-            if (text == null)
-            {
-                throw new ArgumentNullException("text");
-            }
             int textLength = text.Length;
             if (!HasValue || _count < textLength)
             {
@@ -475,12 +467,8 @@ namespace Microsoft.AspNet.PipelineCore.Infrastructure
             return string.Compare(_buffer, _offset + _count - textLength, text, 0, textLength, comparisonType) == 0;
         }
 
-        public bool Equals(string text, StringComparison comparisonType)
+        public bool Equals([NotNull] string text, StringComparison comparisonType)
         {
-            if (text == null)
-            {
-                throw new ArgumentNullException("text");
-            }
             int textLength = text.Length;
             if (!HasValue || _count != textLength)
             {
@@ -615,25 +603,17 @@ namespace Microsoft.AspNet.PipelineCore.Infrastructure
             }
         }
 
-        public static string[] GetHeaderUnmodified(IDictionary<string, string[]> headers, string key)
+        public static string[] GetHeaderUnmodified([NotNull] IDictionary<string, string[]> headers, string key)
         {
-            if (headers == null)
-            {
-                throw new ArgumentNullException("headers");
-            }
             string[] values;
             return headers.TryGetValue(key, out values) ? values : null;
         }
 
-        public static void SetHeader(IDictionary<string, string[]> headers, string key, string value)
+        public static void SetHeader([NotNull] IDictionary<string, string[]> headers, [NotNull] string key, string value)
         {
-            if (headers == null)
-            {
-                throw new ArgumentNullException("headers");
-            }
             if (string.IsNullOrWhiteSpace(key))
             {
-                throw new ArgumentNullException("key");
+                throw new ArgumentNullException(nameof(key));
             }
             if (string.IsNullOrWhiteSpace(value))
             {
@@ -645,15 +625,11 @@ namespace Microsoft.AspNet.PipelineCore.Infrastructure
             }
         }
 
-        public static void SetHeaderJoined(IDictionary<string, string[]> headers, string key, params string[] values)
+        public static void SetHeaderJoined([NotNull] IDictionary<string, string[]> headers, [NotNull] string key, params string[] values)
         {
-            if (headers == null)
-            {
-                throw new ArgumentNullException("headers");
-            }
             if (string.IsNullOrWhiteSpace(key))
             {
-                throw new ArgumentNullException("key");
+                throw new ArgumentNullException(nameof(key));
             }
             if (values == null || values.Length == 0)
             {
@@ -697,15 +673,11 @@ namespace Microsoft.AspNet.PipelineCore.Infrastructure
             return value;
         }
 
-        public static void SetHeaderUnmodified(IDictionary<string, string[]> headers, string key, params string[] values)
+        public static void SetHeaderUnmodified([NotNull] IDictionary<string, string[]> headers, [NotNull] string key, params string[] values)
         {
-            if (headers == null)
-            {
-                throw new ArgumentNullException("headers");
-            }
             if (string.IsNullOrWhiteSpace(key))
             {
-                throw new ArgumentNullException("key");
+                throw new ArgumentNullException(nameof(key));
             }
             if (values == null || values.Length == 0)
             {
@@ -717,16 +689,12 @@ namespace Microsoft.AspNet.PipelineCore.Infrastructure
             }
         }
 
-        public static void SetHeaderUnmodified(IDictionary<string, string[]> headers, string key, IEnumerable<string> values)
+        public static void SetHeaderUnmodified([NotNull] IDictionary<string, string[]> headers, [NotNull] string key, [NotNull] IEnumerable<string> values)
         {
-            if (headers == null)
-            {
-                throw new ArgumentNullException("headers");
-            }
             headers[key] = values.ToArray();
         }
 
-        public static void AppendHeader(IDictionary<string, string[]> headers, string key, string values)
+        public static void AppendHeader([NotNull] IDictionary<string, string[]> headers, [NotNull] string key, string values)
         {
             if (string.IsNullOrWhiteSpace(values))
             {
@@ -744,7 +712,7 @@ namespace Microsoft.AspNet.PipelineCore.Infrastructure
             }
         }
 
-        public static void AppendHeaderJoined(IDictionary<string, string[]> headers, string key, params string[] values)
+        public static void AppendHeaderJoined([NotNull] IDictionary<string, string[]> headers, [NotNull] string key, params string[] values)
         {
             if (values == null || values.Length == 0)
             {
@@ -762,7 +730,7 @@ namespace Microsoft.AspNet.PipelineCore.Infrastructure
             }
         }
 
-        public static void AppendHeaderUnmodified(IDictionary<string, string[]> headers, string key, params string[] values)
+        public static void AppendHeaderUnmodified([NotNull] IDictionary<string, string[]> headers, [NotNull] string key, params string[] values)
         {
             if (values == null || values.Length == 0)
             {
@@ -801,12 +769,8 @@ namespace Microsoft.AspNet.PipelineCore.Infrastructure
             return values == null ? null : string.Join(",", values);
         }
 
-        internal static string[] GetUnmodifiedValues(IDictionary<string, string[]> store, string key)
+        internal static string[] GetUnmodifiedValues([NotNull] IDictionary<string, string[]> store, string key)
         {
-            if (store == null)
-            {
-                throw new ArgumentNullException("store");
-            }
             string[] values;
             return store.TryGetValue(key, out values) ? values : null;
         }
@@ -826,7 +790,7 @@ namespace Microsoft.AspNet.PipelineCore.Infrastructure
         //    return string.IsNullOrWhiteSpace(localPort) ? localIpAddress : (localIpAddress + ":" + localPort);
         //}
 
-        public static long? GetContentLength(IHeaderDictionary headers)
+        public static long? GetContentLength([NotNull] IHeaderDictionary headers)
         {
             const NumberStyles styles = NumberStyles.AllowLeadingWhite | NumberStyles.AllowTrailingWhite;
             long value;
@@ -840,7 +804,7 @@ namespace Microsoft.AspNet.PipelineCore.Infrastructure
             return null;
         }
 
-        public static void SetContentLength(IHeaderDictionary headers, long? value)
+        public static void SetContentLength([NotNull] IHeaderDictionary headers, long? value)
         {
             if (value.HasValue)
             {

src/Microsoft.AspNet.PipelineCore/QueryFeature.cs

@@ -5,9 +5,9 @@ using System.Collections.Generic;
 using Microsoft.AspNet.FeatureModel;
 using Microsoft.AspNet.Http;
 using Microsoft.AspNet.HttpFeature;
+using Microsoft.AspNet.PipelineCore.Collections;
 using Microsoft.AspNet.PipelineCore.Infrastructure;
 using Microsoft.AspNet.WebUtilities;
-using Microsoft.AspNet.WebUtilities.Collections;
 
 namespace Microsoft.AspNet.PipelineCore
 {
@@ -46,7 +46,7 @@ namespace Microsoft.AspNet.PipelineCore
                 if (_query == null || _queryString != queryString)
                 {
                     _queryString = queryString;
-                    _query = QueryHelpers.ParseQuery(queryString);
+                    _query = new ReadableStringCollection(QueryHelpers.ParseQuery(queryString));
                 }
                 return _query;
             }

src/Microsoft.AspNet.PipelineCore/ReferenceReadStream.cs

@@ -0,0 +1,199 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.AspNet.PipelineCore
+{
+    /// <summary>
+    /// A Stream that wraps another stream starting at a certain offset and reading for the given length.
+    /// </summary>
+    internal class ReferenceReadStream : Stream
+    {
+        private readonly Stream _inner;
+        private readonly long _innerOffset;
+        private readonly long _length;
+        private long _position;
+
+        private bool _disposed;
+
+        public ReferenceReadStream([NotNull] Stream inner, long offset, long length)
+        {
+            _inner = inner;
+            _innerOffset = offset;
+            _length = length;
+            _inner.Position = offset;
+        }
+
+        public override bool CanRead
+        {
+            get { return true; }
+        }
+
+        public override bool CanSeek
+        {
+            get { return _inner.CanSeek; }
+        }
+
+        public override bool CanWrite
+        {
+            get { return false; }
+        }
+
+        public override long Length
+        {
+            get { return _length; }
+        }
+
+        public override long Position
+        {
+            get { return _position; }
+            set
+            {
+                ThrowIfDisposed();
+                if (value < 0 || value > Length)
+                {
+                    throw new ArgumentOutOfRangeException("value", value, "The Position must be within the length of the Stream: " + Length);
+                }
+                VerifyPosition();
+                _position = value;
+                _inner.Position = _innerOffset + _position;
+            }
+        }
+
+        // Throws if the position in the underlying stream has changed without our knowledge, indicating someone else is trying
+        // to use the stream at the same time which could lead to data corruption.
+        private void VerifyPosition()
+        {
+            if (_inner.Position != _innerOffset + _position)
+            {
+                throw new InvalidOperationException("The inner stream position has changed unexpectedly.");
+            }
+        }
+
+        public override long Seek(long offset, SeekOrigin origin)
+        {
+            if (origin == SeekOrigin.Begin)
+            {
+                Position = offset;
+            }
+            else if (origin == SeekOrigin.End)
+            {
+                Position = Length + offset;
+            }
+            else // if (origin == SeekOrigin.Current)
+            {
+                Position = Position + offset;
+            }
+            return Position;
+        }
+
+        public override int Read(byte[] buffer, int offset, int count)
+        {
+            ThrowIfDisposed();
+            VerifyPosition();
+            var toRead = Math.Min(count, _length - _position);
+            var read = _inner.Read(buffer, offset, (int)toRead);
+            _position += read;
+            return read;
+        }
+
+        public override async Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        {
+            ThrowIfDisposed();
+            VerifyPosition();
+            var toRead = Math.Min(count, _length - _position);
+            var read = await _inner.ReadAsync(buffer, offset, (int)toRead, cancellationToken);
+            _position += read;
+            return read;
+        }
+#if ASPNET50
+        public override IAsyncResult BeginRead(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
+        {
+            ThrowIfDisposed();
+            VerifyPosition();
+            var tcs = new TaskCompletionSource<int>(state);
+            BeginRead(buffer, offset, count, callback, tcs);
+            return tcs.Task;
+        }
+
+        private async void BeginRead(byte[] buffer, int offset, int count, AsyncCallback callback, TaskCompletionSource<int> tcs)
+        {
+            try
+            {
+                var read = await ReadAsync(buffer, offset, count);
+                tcs.TrySetResult(read);
+            }
+            catch (Exception ex)
+            {
+                tcs.TrySetException(ex);
+            }
+
+            if (callback != null)
+            {
+                try
+                {
+                    callback(tcs.Task);
+                }
+                catch (Exception)
+                {
+                    // Suppress exceptions on background threads.
+                }
+            }
+        }
+
+        public override int EndRead(IAsyncResult asyncResult)
+        {
+            var task = (Task<int>)asyncResult;
+            return task.GetAwaiter().GetResult();
+        }
+#endif
+        public override void Write(byte[] buffer, int offset, int count)
+        {
+            throw new NotSupportedException();
+        }
+        public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        {
+            throw new NotSupportedException();
+        }
+#if ASPNET50
+        public override IAsyncResult BeginWrite(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
+        {
+            throw new NotSupportedException();
+        }
+
+        public override void EndWrite(IAsyncResult asyncResult)
+        {
+            throw new NotSupportedException();
+        }
+#endif
+        public override void SetLength(long value)
+        {
+            throw new NotSupportedException();
+        }
+
+        public override void Flush()
+        {
+            throw new NotSupportedException();
+        }
+
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                _disposed = true;
+            }
+        }
+
+        private void ThrowIfDisposed()
+        {
+            if (_disposed)
+            {
+                throw new ObjectDisposedException(nameof(ReferenceReadStream));
+            }
+        }
+    }
+}

src/Microsoft.AspNet.PipelineCore/RequestCookiesFeature.cs

@@ -9,7 +9,6 @@ using Microsoft.AspNet.Http.Infrastructure;
 using Microsoft.AspNet.HttpFeature;
 using Microsoft.AspNet.PipelineCore.Collections;
 using Microsoft.AspNet.PipelineCore.Infrastructure;
-using Microsoft.AspNet.WebUtilities.Collections;
 
 namespace Microsoft.AspNet.PipelineCore
 {

src/Microsoft.AspNet.PipelineCore/Security/AuthenticateContext.cs

@@ -17,12 +17,8 @@ namespace Microsoft.AspNet.PipelineCore.Security
         private List<AuthenticationResult> _results;
         private List<string> _accepted;
 
-        public AuthenticateContext(IEnumerable<string> authenticationTypes)
+        public AuthenticateContext([NotNull] IEnumerable<string> authenticationTypes)
         {
-            if (authenticationTypes == null)
-            {
-                throw new ArgumentNullException("authenticationType");
-            }
             AuthenticationTypes = authenticationTypes;
             _results = new List<AuthenticationResult>();
             _accepted = new List<string>();

src/Microsoft.AspNet.PipelineCore/Security/ChallengeContext.cs

@@ -14,12 +14,8 @@ namespace Microsoft.AspNet.PipelineCore.Security
     {
         private List<string> _accepted;
 
-        public ChallengeContext(IEnumerable<string> authenticationTypes, IDictionary<string, string> properties)
+        public ChallengeContext([NotNull] IEnumerable<string> authenticationTypes, IDictionary<string, string> properties)
         {
-            if (authenticationTypes == null)
-            {
-                throw new ArgumentNullException();
-            }
             AuthenticationTypes = authenticationTypes;
             Properties = properties ?? new Dictionary<string, string>(StringComparer.Ordinal);
             _accepted = new List<string>();
@@ -33,7 +29,7 @@ namespace Microsoft.AspNet.PipelineCore.Security
         {
             get { return _accepted; }
         }
-        
+
         public void Accept(string authenticationType, IDictionary<string, object> description)
         {
             _accepted.Add(authenticationType);

src/Microsoft.AspNet.PipelineCore/Security/SignInContext.cs

@@ -12,12 +12,8 @@ namespace Microsoft.AspNet.PipelineCore.Security
     {
         private List<string> _accepted;
 
-        public SignInContext(IEnumerable<ClaimsIdentity> identities, IDictionary<string, string> dictionary)
+        public SignInContext([NotNull] IEnumerable<ClaimsIdentity> identities, IDictionary<string, string> dictionary)
         {
-            if (identities == null)
-            {
-                throw new ArgumentNullException("identities");
-            }
             Identities = identities;
             Properties = dictionary ?? new Dictionary<string, string>(StringComparer.Ordinal);
             _accepted = new List<string>();

src/Microsoft.AspNet.PipelineCore/Security/SignOutContext.cs

@@ -11,12 +11,8 @@ namespace Microsoft.AspNet.PipelineCore.Security
     {
         private List<string> _accepted;
 
-        public SignOutContext(IEnumerable<string> authenticationTypes)
+        public SignOutContext([NotNull] IEnumerable<string> authenticationTypes)
         {
-            if (authenticationTypes == null)
-            {
-                throw new ArgumentNullException("authenticationTypes");
-            }
             AuthenticationTypes = authenticationTypes;
             _accepted = new List<string>();
         }

src/Microsoft.AspNet.WebUtilities/BufferedReadStream.cs

@@ -0,0 +1,396 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.IO;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.AspNet.WebUtilities
+{
+    internal class BufferedReadStream : Stream
+    {
+        private const char CR = '\r';
+        private const char LF = '\n';
+
+        private readonly Stream _inner;
+        private readonly byte[] _buffer;
+        private int _bufferOffset = 0;
+        private int _bufferCount = 0;
+        private bool _disposed;
+
+        public BufferedReadStream([NotNull] Stream inner, int bufferSize)
+        {
+            _inner = inner;
+            _buffer = new byte[bufferSize];
+        }
+
+        public ArraySegment<byte> BufferedData
+        {
+            get { return new ArraySegment<byte>(_buffer, _bufferOffset, _bufferCount); }
+        }
+
+        public override bool CanRead
+        {
+            get { return _inner.CanRead || _bufferCount > 0; }
+        }
+
+        public override bool CanSeek
+        {
+            get { return _inner.CanSeek; }
+        }
+
+        public override bool CanTimeout
+        {
+            get { return _inner.CanTimeout; }
+        }
+
+        public override bool CanWrite
+        {
+            get { return _inner.CanWrite; }
+        }
+
+        public override long Length
+        {
+            get { return _inner.Length; }
+        }
+
+        public override long Position
+        {
+            get { return _inner.Position - _bufferCount; }
+            set
+            {
+                if (value < 0)
+                {
+                    throw new ArgumentOutOfRangeException("value", value, "Position must be positive.");
+                }
+                if (value == Position)
+                {
+                    return;
+                }
+
+                // Backwards?
+                if (value <= _inner.Position)
+                {
+                    // Forward within the buffer?
+                    var innerOffset = (int)(_inner.Position - value);
+                    if (innerOffset <= _bufferCount)
+                    {
+                        // Yes, just skip some of the buffered data
+                        _bufferOffset += innerOffset;
+                        _bufferCount -= innerOffset;
+                    }
+                    else
+                    {
+                        // No, reset the buffer
+                        _bufferOffset = 0;
+                        _bufferCount = 0;
+                        _inner.Position = value;
+                    }
+                }
+                else
+                {
+                    // Forward, reset the buffer
+                    _bufferOffset = 0;
+                    _bufferCount = 0;
+                    _inner.Position = value;
+                }
+            }
+        }
+
+        public override long Seek(long offset, SeekOrigin origin)
+        {
+            if (origin == SeekOrigin.Begin)
+            {
+                Position = offset;
+            }
+            else if (origin == SeekOrigin.Current)
+            {
+                Position = Position + offset;
+            }
+            else // if (origin == SeekOrigin.End)
+            {
+                Position = Length + offset;
+            }
+            return Position;
+        }
+
+        public override void SetLength(long value)
+        {
+            _inner.SetLength(value);
+        }
+
+        protected override void Dispose(bool disposing)
+        {
+            _disposed = true;
+            if (disposing)
+            {
+                _inner.Dispose();
+            }
+        }
+
+        public override void Flush()
+        {
+            _inner.Flush();
+        }
+
+        public override Task FlushAsync(CancellationToken cancellationToken)
+        {
+            return _inner.FlushAsync(cancellationToken);
+        }
+
+        public override void Write(byte[] buffer, int offset, int count)
+        {
+            _inner.Write(buffer, offset, count);
+        }
+#if ASPNET50
+        public override IAsyncResult BeginWrite(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
+        {
+            return _inner.BeginWrite(buffer, offset, count, callback, state);
+        }
+
+        public override void EndWrite(IAsyncResult asyncResult)
+        {
+            _inner.EndWrite(asyncResult);
+        }
+#endif
+        public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        {
+            return _inner.WriteAsync(buffer, offset, count, cancellationToken);
+        }
+
+        public override int Read(byte[] buffer, int offset, int count)
+        {
+            ValidateBuffer(buffer, offset, count);
+
+            // Drain buffer
+            if (_bufferCount > 0)
+            {
+                int toCopy = Math.Min(_bufferCount, count);
+                Buffer.BlockCopy(_buffer, _bufferOffset, buffer, offset, toCopy);
+                _bufferOffset += toCopy;
+                _bufferCount -= toCopy;
+                return toCopy;
+            }
+
+            return _inner.Read(buffer, offset, count);
+        }
+
+        public async override Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        {
+            ValidateBuffer(buffer, offset, count);
+
+            // Drain buffer
+            if (_bufferCount > 0)
+            {
+                int toCopy = Math.Min(_bufferCount, count);
+                Buffer.BlockCopy(_buffer, _bufferOffset, buffer, offset, toCopy);
+                _bufferOffset += toCopy;
+                _bufferCount -= toCopy;
+                return toCopy;
+            }
+
+            return await _inner.ReadAsync(buffer, offset, count, cancellationToken);
+        }
+#if ASPNET50
+        // We only anticipate using ReadAsync
+        public override IAsyncResult BeginRead(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
+        {
+            ValidateBuffer(buffer, offset, count);
+
+            // Drain buffer
+            if (_bufferCount > 0)
+            {
+                int toCopy = Math.Min(_bufferCount, count);
+                Buffer.BlockCopy(_buffer, _bufferOffset, buffer, offset, toCopy);
+                _bufferOffset += toCopy;
+                _bufferCount -= toCopy;
+
+                TaskCompletionSource<int> tcs = new TaskCompletionSource<int>(state);
+                tcs.TrySetResult(toCopy);
+                if (callback != null)
+                {
+                    callback(tcs.Task);
+                }
+                return tcs.Task;
+            }
+
+            return _inner.BeginRead(buffer, offset, count, callback, state);
+        }
+
+        public override int EndRead(IAsyncResult asyncResult)
+        {
+            Task<int> task = asyncResult as Task<int>;
+            if (task != null)
+            {
+                return task.GetAwaiter().GetResult();
+            }
+            return _inner.EndRead(asyncResult);
+        }
+#endif
+        public bool EnsureBuffered()
+        {
+            if (_bufferCount > 0)
+            {
+                return true;
+            }
+            // Downshift to make room
+            _bufferOffset = 0;
+            _bufferCount = _inner.Read(_buffer, 0, _buffer.Length);
+            return _bufferCount > 0;
+        }
+
+        public async Task<bool> EnsureBufferedAsync(CancellationToken cancellationToken)
+        {
+            if (_bufferCount > 0)
+            {
+                return true;
+            }
+            // Downshift to make room
+            _bufferOffset = 0;
+            _bufferCount = await _inner.ReadAsync(_buffer, 0, _buffer.Length, cancellationToken);
+            return _bufferCount > 0;
+        }
+
+        public bool EnsureBuffered(int minCount)
+        {
+            if (minCount > _buffer.Length)
+            {
+                throw new ArgumentOutOfRangeException(nameof(minCount), minCount, "The value must be smaller than the buffer size: " + _buffer.Length);
+            }
+            while (_bufferCount < minCount)
+            {
+                // Downshift to make room
+                if (_bufferOffset > 0)
+                {
+                    if (_bufferCount > 0)
+                    {
+                        Buffer.BlockCopy(_buffer, _bufferOffset, _buffer, 0, _bufferCount);
+                    }
+                    _bufferOffset = 0;
+                }
+                int read = _inner.Read(_buffer, _bufferOffset + _bufferCount, _buffer.Length - _bufferCount - _bufferOffset);
+                _bufferCount += read;
+                if (read == 0)
+                {
+                    return false;
+                }
+            }
+            return true;
+        }
+
+        public async Task<bool> EnsureBufferedAsync(int minCount, CancellationToken cancellationToken)
+        {
+            if (minCount > _buffer.Length)
+            {
+                throw new ArgumentOutOfRangeException(nameof(minCount), minCount, "The value must be smaller than the buffer size: " + _buffer.Length);
+            }
+            while (_bufferCount < minCount)
+            {
+                // Downshift to make room
+                if (_bufferOffset > 0)
+                {
+                    if (_bufferCount > 0)
+                    {
+                        Buffer.BlockCopy(_buffer, _bufferOffset, _buffer, 0, _bufferCount);
+                    }
+                    _bufferOffset = 0;
+                }
+                int read = await _inner.ReadAsync(_buffer, _bufferOffset + _bufferCount, _buffer.Length - _bufferCount - _bufferOffset, cancellationToken);
+                _bufferCount += read;
+                if (read == 0)
+                {
+                    return false;
+                }
+            }
+            return true;
+        }
+
+        public string ReadLine(int lengthLimit)
+        {
+            CheckDisposed();
+            StringBuilder builder = new StringBuilder();
+            bool foundCR = false, foundCRLF = false;
+            while (!foundCRLF && EnsureBuffered())
+            {
+                if (builder.Length > lengthLimit)
+                {
+                    throw new InvalidOperationException("Line length limit exceeded: " + lengthLimit);
+                }
+                ProcessLineChar(builder, ref foundCR, ref foundCRLF);
+            }
+
+            if (foundCRLF)
+            {
+                return builder.ToString(0, builder.Length - 2); // Drop the CRLF
+            }
+            // Stream ended with no CRLF.
+            return builder.ToString();
+        }
+
+        public async Task<string> ReadLineAsync(int lengthLimit, CancellationToken cancellationToken)
+        {
+            CheckDisposed();
+            StringBuilder builder = new StringBuilder();
+            bool foundCR = false, foundCRLF = false;
+            while (!foundCRLF && await EnsureBufferedAsync(cancellationToken))
+            {
+                if (builder.Length > lengthLimit)
+                {
+                    throw new InvalidOperationException("Line length limit exceeded: " + lengthLimit);
+                }
+
+                ProcessLineChar(builder, ref foundCR, ref foundCRLF);
+            }
+
+            if (foundCRLF)
+            {
+                return builder.ToString(0, builder.Length - 2); // Drop the CRLF
+            }
+            // Stream ended with no CRLF.
+            return builder.ToString();
+        }
+
+        private void ProcessLineChar(StringBuilder builder, ref bool foundCR, ref bool foundCRLF)
+        {
+            char ch = (char)_buffer[_bufferOffset]; // TODO: Encoding enforcement
+            builder.Append(ch);
+            _bufferOffset++;
+            _bufferCount--;
+            if (ch == CR)
+            {
+                foundCR = true;
+            }
+            else if (ch == LF)
+            {
+                if (foundCR)
+                {
+                    foundCRLF = true;
+                }
+                else
+                {
+                    foundCR = false;
+                }
+            }
+        }
+
+        private void CheckDisposed()
+        {
+            if (_disposed)
+            {
+                throw new ObjectDisposedException(nameof(BufferedReadStream));
+            }
+        }
+
+        private void ValidateBuffer(byte[] buffer, int offset, int count)
+        {
+            // Delegate most of our validation.
+            var ignored = new ArraySegment<byte>(buffer, offset, count);
+            if (count == 0)
+            {
+                throw new ArgumentOutOfRangeException(nameof(count), "The value must be greater than zero.");
+            }
+        }
+    }
+}

src/Microsoft.AspNet.WebUtilities/FileBufferingReadStream.cs

@@ -0,0 +1,248 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.AspNet.WebUtilities
+{
+    /// <summary>
+    /// A Stream that wraps another stream and enables rewinding by buffering the content as it is read.
+    /// The content is buffered in memory up to a certain size and then spooled to a temp file on disk.
+    /// The temp file will be deleted on Dispose.
+    /// </summary>
+    public class FileBufferingReadStream : Stream
+    {
+        private readonly Stream _inner;
+        private readonly int _memoryThreshold;
+        private readonly string _tempFileDirectory;
+
+        private Stream _buffer = new MemoryStream(); // TODO: We could have a more efficiently expanding buffer stream.
+        private bool _inMemory = true;
+        private bool _completelyBuffered;
+
+        private bool _disposed;
+
+        // TODO: allow for an optional buffer size limit to prevent filling hard disks. 1gb?
+        public FileBufferingReadStream([NotNull] Stream inner, int memoryThreshold, [NotNull] string tempFileDirectory)
+        {
+            _inner = inner;
+            _memoryThreshold = memoryThreshold;
+            _tempFileDirectory = tempFileDirectory;
+        }
+
+        public override bool CanRead
+        {
+            get { return true; }
+        }
+
+        public override bool CanSeek
+        {
+            get { return true; }
+        }
+
+        public override bool CanWrite
+        {
+            get { return false; }
+        }
+
+        public override long Length
+        {
+            get { return _buffer.Length; }
+        }
+
+        public override long Position
+        {
+            get { return _buffer.Position; }
+            // Note this will not allow seeking forward beyond the end of the buffer.
+            set
+            {
+                ThrowIfDisposed();
+                _buffer.Position = value;
+            }
+        }
+
+        public override long Seek(long offset, SeekOrigin origin)
+        {
+            ThrowIfDisposed();
+            if (!_completelyBuffered && origin == SeekOrigin.End)
+            {
+                // Can't seek from the end until we've finished consuming the inner stream
+                throw new NotSupportedException("The content has not been fully buffered yet.");
+            }
+            else if (!_completelyBuffered && origin == SeekOrigin.Current && offset + Position > Length)
+            {
+                // Can't seek past the end of the buffer until we've finished consuming the inner stream
+                throw new NotSupportedException("The content has not been fully buffered yet.");
+            }
+            else if (!_completelyBuffered && origin == SeekOrigin.Begin && offset > Length)
+            {
+                // Can't seek past the end of the buffer until we've finished consuming the inner stream
+                throw new NotSupportedException("The content has not been fully buffered yet.");
+            }
+            return _buffer.Seek(offset, origin);
+        }
+
+        private Stream CreateTempFile()
+        {
+            var fileName = Path.Combine(_tempFileDirectory, "ASPNET_" + Guid.NewGuid().ToString() + ".tmp");
+            return new FileStream(fileName, FileMode.Create, FileAccess.ReadWrite, FileShare.Delete, 1024 * 16,
+                FileOptions.Asynchronous | FileOptions.DeleteOnClose | FileOptions.SequentialScan);
+        }
+
+        public override int Read(byte[] buffer, int offset, int count)
+        {
+            ThrowIfDisposed();
+            if (_buffer.Position < _buffer.Length || _completelyBuffered)
+            {
+                // Just read from the buffer
+                return _buffer.Read(buffer, offset, (int)Math.Min(count, _buffer.Length - _buffer.Position));
+            }
+
+            int read = _inner.Read(buffer, offset, count);
+
+            if (_inMemory && _buffer.Length + read > _memoryThreshold)
+            {
+                var oldBuffer = _buffer;
+                _buffer = CreateTempFile();
+                _inMemory = false;
+                oldBuffer.Position = 0;
+                oldBuffer.CopyTo(_buffer, 1024 * 16);
+            }
+
+            if (read > 0)
+            {
+                _buffer.Write(buffer, offset, read);
+            }
+            else
+            {
+                _completelyBuffered = true;
+            }
+
+            return read;
+        }
+#if ASPNET50
+        public override IAsyncResult BeginRead(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
+        {
+            ThrowIfDisposed();
+            var tcs = new TaskCompletionSource<int>(state);
+            BeginRead(buffer, offset, count, callback, tcs);
+            return tcs.Task;
+        }
+
+        private async void BeginRead(byte[] buffer, int offset, int count, AsyncCallback callback, TaskCompletionSource<int> tcs)
+        {
+            try
+            {
+                var read = await ReadAsync(buffer, offset, count);
+                tcs.TrySetResult(read);
+            }
+            catch (Exception ex)
+            {
+                tcs.TrySetException(ex);
+            }
+
+            if (callback != null)
+            {
+                try
+                {
+                    callback(tcs.Task);
+                }
+                catch (Exception)
+                {
+                    // Suppress exceptions on background threads.
+                }
+            }
+        }
+
+        public override int EndRead(IAsyncResult asyncResult)
+        {
+            var task = (Task<int>)asyncResult;
+            return task.GetAwaiter().GetResult();
+        }
+#endif
+        public override async Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        {
+            ThrowIfDisposed();
+            if (_buffer.Position < _buffer.Length || _completelyBuffered)
+            {
+                // Just read from the buffer
+                return await _buffer.ReadAsync(buffer, offset, (int)Math.Min(count, _buffer.Length - _buffer.Position), cancellationToken);
+            }
+
+            int read = await _inner.ReadAsync(buffer, offset, count, cancellationToken);
+
+            if (_inMemory && _buffer.Length + read > _memoryThreshold)
+            {
+                var oldBuffer = _buffer;
+                _buffer = CreateTempFile();
+                _inMemory = false;
+                oldBuffer.Position = 0;
+                await oldBuffer.CopyToAsync(_buffer, 1024 * 16, cancellationToken);
+            }
+
+            if (read > 0)
+            {
+                await _buffer.WriteAsync(buffer, offset, read, cancellationToken);
+            }
+            else
+            {
+                _completelyBuffered = true;
+            }
+
+            return read;
+        }
+
+        public override void Write(byte[] buffer, int offset, int count)
+        {
+            throw new NotSupportedException();
+        }
+#if ASPNET50
+        public override IAsyncResult BeginWrite(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
+        {
+            throw new NotSupportedException();
+        }
+
+        public override void EndWrite(IAsyncResult asyncResult)
+        {
+            throw new NotSupportedException();
+        }
+#endif
+        public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        {
+            throw new NotSupportedException();
+        }
+
+        public override void SetLength(long value)
+        {
+            throw new NotSupportedException();
+        }
+
+        public override void Flush()
+        {
+            throw new NotSupportedException();
+        }
+
+        protected override void Dispose(bool disposing)
+        {
+            if (!_disposed)
+            {
+                _disposed = true;
+                if (disposing)
+                {
+                    _buffer.Dispose();
+                }
+            }
+        }
+
+        private void ThrowIfDisposed()
+        {
+            if (_disposed)
+            {
+                throw new ObjectDisposedException(nameof(FileBufferingReadStream));
+            }
+        }
+    }
+}

src/Microsoft.AspNet.WebUtilities/FormHelpers.cs

@@ -1,21 +0,0 @@
-// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
-// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
-
-using System;
-using Microsoft.AspNet.Http;
-
-namespace Microsoft.AspNet.WebUtilities
-{
-    public static class FormHelpers
-    {
-        /// <summary>
-        /// Parses an HTTP form body.
-        /// </summary>
-        /// <param name="text">The HTTP form body to parse.</param>
-        /// <returns>The <see cref="T:Microsoft.Owin.IFormCollection" /> object containing the parsed HTTP form body.</returns>
-        public static IFormCollection ParseForm(string text)
-        {
-            return ParsingHelpers.GetForm(text);
-        }
-    }
-}

src/Microsoft.AspNet.WebUtilities/FormReader.cs

@@ -0,0 +1,188 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.AspNet.WebUtilities
+{
+    /// <summary>
+    /// Used to read an 'application/x-www-form-urlencoded' form.
+    /// </summary>
+    public class FormReader
+    {
+        private readonly TextReader _reader;
+        private readonly char[] _buffer = new char[1024];
+        private readonly StringBuilder _builder = new StringBuilder();
+        private int _bufferOffset;
+        private int _bufferCount;
+
+        public FormReader([NotNull] string data)
+        {
+            _reader = new StringReader(data);
+        }
+
+        // TODO: Encoding
+        public FormReader([NotNull] Stream stream)
+        {
+            _reader = new StreamReader(stream, Encoding.UTF8, detectEncodingFromByteOrderMarks: true, bufferSize: 1024 * 2, leaveOpen: true);
+        }
+
+        // Format: key1=value1&key2=value2
+        /// <summary>
+        /// Reads the next key value pair from the form.
+        /// For unbuffered data use the async overload instead.
+        /// </summary>
+        /// <returns>The next key value pair, or null when the end of the form is reached.</returns>
+        public KeyValuePair<string, string>? ReadNextPair()
+        {
+            var key = ReadWord('=');
+            if (string.IsNullOrEmpty(key) && _bufferCount == 0)
+            {
+                return null;
+            }
+            var value = ReadWord('&');
+            return new KeyValuePair<string, string>(key, value);
+        }
+
+        // Format: key1=value1&key2=value2
+        /// <summary>
+        /// Asynchronously reads the next key value pair from the form.
+        /// </summary>
+        /// <param name="cancellationToken"></param>
+        /// <returns>The next key value pair, or null when the end of the form is reached.</returns>
+        public async Task<KeyValuePair<string, string>?> ReadNextPairAsync(CancellationToken cancellationToken)
+        {
+            var key = await ReadWordAsync('=', cancellationToken);
+            if (string.IsNullOrEmpty(key) && _bufferCount == 0)
+            {
+                return null;
+            }
+            var value = await ReadWordAsync('&', cancellationToken);
+            return new KeyValuePair<string, string>(key, value);
+        }
+
+        private string ReadWord(char seperator)
+        {
+            // TODO: Configurable value size limit
+            while (true)
+            {
+                // Empty
+                if (_bufferCount == 0)
+                {
+                    Buffer();
+                }
+
+                // End
+                if (_bufferCount == 0)
+                {
+                    return BuildWord();
+                }
+
+                var c = _buffer[_bufferOffset++];
+                _bufferCount--;
+
+                if (c == seperator)
+                {
+                    return BuildWord();
+                }
+                _builder.Append(c);
+            }
+        }
+
+        private async Task<string> ReadWordAsync(char seperator, CancellationToken cancellationToken)
+        {
+            // TODO: Configurable value size limit
+            while (true)
+            {
+                // Empty
+                if (_bufferCount == 0)
+                {
+                    await BufferAsync(cancellationToken);
+                }
+
+                // End
+                if (_bufferCount == 0)
+                {
+                    return BuildWord();
+                }
+
+                var c = _buffer[_bufferOffset++];
+                _bufferCount--;
+
+                if (c == seperator)
+                {
+                    return BuildWord();
+                }
+                _builder.Append(c);
+            }
+        }
+
+        // '+' un-escapes to ' ', %HH un-escapes as ASCII (or utf-8?)
+        private string BuildWord()
+        {
+            _builder.Replace('+', ' ');
+            var result = _builder.ToString();
+            _builder.Clear();
+            return Uri.UnescapeDataString(result); // TODO: Replace this, it's not completely accurate.
+        }
+
+        private void Buffer()
+        {
+            _bufferOffset = 0;
+            _bufferCount = _reader.Read(_buffer, 0, _buffer.Length);
+        }
+
+        private async Task BufferAsync(CancellationToken cancellationToken)
+        {
+            // TODO: StreamReader doesn't support cancellation?
+            cancellationToken.ThrowIfCancellationRequested();
+            _bufferOffset = 0;
+            _bufferCount = await _reader.ReadAsync(_buffer, 0, _buffer.Length);
+        }
+
+        /// <summary>
+        /// Parses text from an HTTP form body.
+        /// </summary>
+        /// <param name="text">The HTTP form body to parse.</param>
+        /// <returns>The collection containing the parsed HTTP form body.</returns>
+        public static IDictionary<string, string[]> ReadForm(string text)
+        {
+            var reader = new FormReader(text);
+
+            var accumulator = new KeyValueAccumulator<string, string>(StringComparer.OrdinalIgnoreCase);
+            var pair = reader.ReadNextPair();
+            while (pair.HasValue)
+            {
+                accumulator.Append(pair.Value.Key, pair.Value.Value);
+                pair =  reader.ReadNextPair();
+            }
+
+            return accumulator.GetResults();
+        }
+
+        /// <summary>
+        /// Parses an HTTP form body.
+        /// </summary>
+        /// <param name="text">The HTTP form body to parse.</param>
+        /// <returns>The collection containing the parsed HTTP form body.</returns>
+        public static async Task<IDictionary<string, string[]>> ReadFormAsync(Stream stream, CancellationToken cancellationToken = new CancellationToken())
+        {
+            var reader = new FormReader(stream);
+
+            var accumulator = new KeyValueAccumulator<string, string>(StringComparer.OrdinalIgnoreCase);
+            var pair = await reader.ReadNextPairAsync(cancellationToken);
+            while (pair.HasValue)
+            {
+                accumulator.Append(pair.Value.Key, pair.Value.Value);
+                pair = await reader.ReadNextPairAsync(cancellationToken);
+            }
+
+            return accumulator.GetResults();
+        }
+    }
+}

src/Microsoft.AspNet.WebUtilities/KeyValueAccumulator.cs

@@ -0,0 +1,42 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+
+namespace Microsoft.AspNet.WebUtilities
+{
+    public class KeyValueAccumulator<TKey, TValue>
+    {
+        private Dictionary<TKey, List<TValue>> _accumulator;
+        IEqualityComparer<TKey> _comparer;
+
+        public KeyValueAccumulator([NotNull] IEqualityComparer<TKey> comparer)
+        {
+            _comparer = comparer;
+            _accumulator = new Dictionary<TKey, List<TValue>>(comparer);
+        }
+
+        public void Append(TKey key, TValue value)
+        {
+            List<TValue> values;
+            if (_accumulator.TryGetValue(key, out values))
+            {
+                values.Add(value);
+            }
+            else
+            {
+                _accumulator[key] = new List<TValue>(1) { value };
+            }
+        }
+
+        public IDictionary<TKey, TValue[]> GetResults()
+        {
+            var results = new Dictionary<TKey, TValue[]>(_comparer);
+            foreach (var kv in _accumulator)
+            {
+                results.Add(kv.Key, kv.Value.ToArray());
+            }
+            return results;
+        }
+    }
+}

src/Microsoft.AspNet.WebUtilities/MultipartReader.cs

@@ -0,0 +1,92 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.AspNet.WebUtilities
+{
+    // https://www.ietf.org/rfc/rfc2046.txt
+    public class MultipartReader
+    {
+        private const int DefaultBufferSize = 1024 * 4;
+
+        private readonly BufferedReadStream _stream;
+        private readonly string _boundary;
+        private MultipartReaderStream _currentStream;
+
+        public MultipartReader([NotNull] string boundary, [NotNull] Stream stream)
+            : this(boundary, stream, DefaultBufferSize)
+        {
+        }
+
+        public MultipartReader([NotNull] string boundary, [NotNull] Stream stream, int bufferSize)
+        {
+            if (bufferSize < boundary.Length + 8) // Size of the boundary + leading and trailing CRLF + leading and trailing '--' markers.
+            {
+                throw new ArgumentOutOfRangeException(nameof(bufferSize), bufferSize, "Insufficient buffer space, the buffer must be larger than the boundary: " + boundary);
+            }
+            _stream = new BufferedReadStream(stream, bufferSize);
+            _boundary = boundary;
+            // This stream will drain any preamble data and remove the first boundary marker.
+            _currentStream = new MultipartReaderStream(_stream, _boundary, expectLeadingCrlf: false);
+        }
+
+        /// <summary>
+        /// The limit for individual header lines inside a multipart section.
+        /// </summary>
+        public int HeaderLengthLimit { get; set; } = 1024 * 4;
+
+        /// <summary>
+        /// The combined size limit for headers per multipart section.
+        /// </summary>
+        public int TotalHeaderSizeLimit { get; set; } = 1024 * 16;
+
+        public async Task<MultipartSection> ReadNextSectionAsync(CancellationToken cancellationToken = new CancellationToken())
+        {
+            // Drain the prior section.
+            await _currentStream.DrainAsync(cancellationToken);
+            // If we're at the end return null
+            if (_currentStream.FinalBoundaryFound)
+            {
+                // There may be trailer data after the last boundary.
+                await _stream.DrainAsync(cancellationToken);
+                return null;
+            }
+            var headers = await ReadHeadersAsync(cancellationToken);
+            _currentStream = new MultipartReaderStream(_stream, _boundary);
+            long? baseStreamOffset = _stream.CanSeek ? (long?)_stream.Position : null;
+            return new MultipartSection() { Headers = headers, Body = _currentStream, BaseStreamOffset = baseStreamOffset };
+        }
+
+        private async Task<IDictionary<string, string[]>> ReadHeadersAsync(CancellationToken cancellationToken)
+        {
+            int totalSize = 0;
+            var accumulator = new KeyValueAccumulator<string, string>(StringComparer.OrdinalIgnoreCase);
+            var line = await _stream.ReadLineAsync(HeaderLengthLimit, cancellationToken);
+            while (!string.IsNullOrEmpty(line))
+            {
+                totalSize += line.Length;
+                if (totalSize > TotalHeaderSizeLimit)
+                {
+                    throw new InvalidOperationException("Total header size limit exceeded: " + TotalHeaderSizeLimit);
+                }
+                int splitIndex = line.IndexOf(':');
+                Debug.Assert(splitIndex > 0, "Invalid header line: " + line);
+                if (splitIndex >= 0)
+                {
+                    var name = line.Substring(0, splitIndex);
+                    var value = line.Substring(splitIndex + 1, line.Length - splitIndex - 1).Trim();
+                    accumulator.Append(name, value);
+                }
+                line = await _stream.ReadLineAsync(HeaderLengthLimit, cancellationToken);
+            }
+
+            return accumulator.GetResults();
+        }
+    }
+}

src/Microsoft.AspNet.WebUtilities/MultipartReaderStream.cs

@@ -0,0 +1,320 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Diagnostics;
+using System.IO;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.AspNet.WebUtilities
+{
+    internal class MultipartReaderStream : Stream
+    {
+        private readonly BufferedReadStream _innerStream;
+        private readonly byte[] _boundaryBytes;
+        private readonly int _finalBoundaryLength;
+        private readonly long _innerOffset;
+        private long _position;
+        private long _observedLength;
+        private bool _finished;
+
+        /// <summary>
+        /// Creates a stream that reads until it reaches the given boundary pattern.
+        /// </summary>
+        /// <param name="stream"></param>
+        /// <param name="boundary"></param>
+        public MultipartReaderStream([NotNull] BufferedReadStream stream, [NotNull] string boundary, bool expectLeadingCrlf = true)
+        {
+            _innerStream = stream;
+            _innerOffset = _innerStream.CanSeek ? _innerStream.Position : 0;
+            if (expectLeadingCrlf)
+            {
+                _boundaryBytes = Encoding.UTF8.GetBytes("\r\n--" + boundary);
+            }
+            else
+            {
+                _boundaryBytes = Encoding.UTF8.GetBytes("--" + boundary);
+            }
+            _finalBoundaryLength = _boundaryBytes.Length + 2; // Include the final '--' terminator.
+        }
+
+        public bool FinalBoundaryFound { get; private set; }
+
+        public override bool CanRead
+        {
+            get { return true; }
+        }
+
+        public override bool CanSeek
+        {
+            get { return _innerStream.CanSeek; }
+        }
+
+        public override bool CanWrite
+        {
+            get { return false; }
+        }
+
+        public override long Length
+        {
+            get { return _observedLength; }
+        }
+
+        public override long Position
+        {
+            get { return _position; }
+            set
+            {
+                if (value < 0)
+                {
+                    throw new ArgumentOutOfRangeException("value", value, "The Position must be positive.");
+                }
+                if (value > _observedLength)
+                {
+                    throw new ArgumentOutOfRangeException("value", value, "The Position must be less than length.");
+                }
+                _position = value;
+                if (_position < _observedLength)
+                {
+                    _finished = false;
+                }
+            }
+        }
+
+        public override long Seek(long offset, SeekOrigin origin)
+        {
+            if (origin == SeekOrigin.Begin)
+            {
+                Position = offset;
+            }
+            else if (origin == SeekOrigin.Current)
+            {
+                Position = Position + offset;
+            }
+            else // if (origin == SeekOrigin.End)
+            {
+                Position = Length + offset;
+            }
+            return Position;
+        }
+
+        public override void SetLength(long value)
+        {
+            throw new NotSupportedException();
+        }
+
+        public override void Write(byte[] buffer, int offset, int count)
+        {
+            throw new NotSupportedException();
+        }
+#if ASPNET50
+        public override IAsyncResult BeginWrite(byte[] buffer, int offset, int size, AsyncCallback callback, object state)
+        {
+            throw new NotSupportedException();
+        }
+
+        public override void EndWrite(IAsyncResult asyncResult)
+        {
+            throw new NotSupportedException();
+        }
+#endif
+        public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        {
+            throw new NotSupportedException();
+        }
+
+        public override void Flush()
+        {
+            throw new NotSupportedException();
+        }
+
+        private void PositionInnerStream()
+        {
+            if (_innerStream.CanSeek && _innerStream.Position != (_innerOffset + _position))
+            {
+                _innerStream.Position = _innerOffset + _position;
+            }
+        }
+
+        private int UpdatePosition(int read)
+        {
+            _position += read;
+            if (_observedLength < _position)
+            {
+                _observedLength = _position;
+            }
+            return read;
+        }
+#if ASPNET50
+        public override IAsyncResult BeginRead(byte[] buffer, int offset, int size, AsyncCallback callback, object state)
+        {
+            var tcs = new TaskCompletionSource<int>(state);
+            InternalReadAsync(buffer, offset, size, callback, tcs);
+            return tcs.Task;
+        }
+
+        private async void InternalReadAsync(byte[] buffer, int offset, int size, AsyncCallback callback, TaskCompletionSource<int> tcs)
+        {
+            try
+            {
+                int read = await ReadAsync(buffer, offset, size);
+                tcs.TrySetResult(read);
+            }
+            catch (Exception ex)
+            {
+                tcs.TrySetException(ex);
+            }
+
+            if (callback != null)
+            {
+                try
+                {
+                    callback(tcs.Task);
+                }
+                catch (Exception)
+                {
+                    // Suppress exceptions on background threads.
+                }
+            }
+        }
+
+        public override int EndRead(IAsyncResult asyncResult)
+        {
+            var task = (Task<int>)asyncResult;
+            return task.GetAwaiter().GetResult();
+        }
+#endif
+        public override int Read(byte[] buffer, int offset, int count)
+        {
+            if (_finished)
+            {
+                return 0;
+            }
+
+            PositionInnerStream();
+            if (!_innerStream.EnsureBuffered(_finalBoundaryLength))
+            {
+                throw new IOException("Unexpected end of stream.");
+            }
+            var bufferedData = _innerStream.BufferedData;
+
+            // scan for a boundary match, full or partial.
+            int matchOffset;
+            int matchCount;
+            int read;
+            if (SubMatch(bufferedData, _boundaryBytes, out matchOffset, out matchCount))
+            {
+                // We found a possible match, return any data before it.
+                if (matchOffset > bufferedData.Offset)
+                {
+                    read = _innerStream.Read(buffer, offset, Math.Min(count, matchOffset - bufferedData.Offset));
+                    return UpdatePosition(read);
+                }
+                Debug.Assert(matchCount == _boundaryBytes.Length);
+
+                // "The boundary may be followed by zero or more characters of
+                // linear whitespace. It is then terminated by either another CRLF"
+                // or -- for the final boundary.
+                byte[] boundary = new byte[_boundaryBytes.Length];
+                read = _innerStream.Read(boundary, 0, boundary.Length);
+                Debug.Assert(read == boundary.Length); // It should have all been buffered
+                var remainder = _innerStream.ReadLine(lengthLimit: 100); // Whitespace may exceed the buffer.
+                remainder = remainder.Trim();
+                if (string.Equals("--", remainder, StringComparison.Ordinal))
+                {
+                    FinalBoundaryFound = true;
+                }
+                Debug.Assert(FinalBoundaryFound || string.Equals(string.Empty, remainder, StringComparison.Ordinal), "Un-expected data found on the boundary line: " + remainder);
+
+                _finished = true;
+                return 0;
+            }
+
+            // No possible boundary match within the buffered data, return the data from the buffer.
+            read = _innerStream.Read(buffer, offset, Math.Min(count, bufferedData.Count));
+            return UpdatePosition(read);
+        }
+
+        public override async Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        {
+            if (_finished)
+            {
+                return 0;
+            }
+
+            PositionInnerStream();
+            if (!await _innerStream.EnsureBufferedAsync(_finalBoundaryLength, cancellationToken))
+            {
+                throw new IOException("Unexpected end of stream.");
+            }
+            var bufferedData = _innerStream.BufferedData;
+
+            // scan for a boundary match, full or partial.
+            int matchOffset;
+            int matchCount;
+            int read;
+            if (SubMatch(bufferedData, _boundaryBytes, out matchOffset, out matchCount))
+            {
+                // We found a possible match, return any data before it.
+                if (matchOffset > bufferedData.Offset)
+                {
+                    // Sync, it's already buffered
+                    read = _innerStream.Read(buffer, offset, Math.Min(count, matchOffset - bufferedData.Offset));
+                    return UpdatePosition(read);
+                }
+                Debug.Assert(matchCount == _boundaryBytes.Length);
+
+                // "The boundary may be followed by zero or more characters of
+                // linear whitespace. It is then terminated by either another CRLF"
+                // or -- for the final boundary.
+                byte[] boundary = new byte[_boundaryBytes.Length];
+                read = _innerStream.Read(boundary, 0, boundary.Length);
+                Debug.Assert(read == boundary.Length); // It should have all been buffered
+                var remainder = await _innerStream.ReadLineAsync(lengthLimit: 100, cancellationToken: cancellationToken); // Whitespace may exceed the buffer.
+                remainder = remainder.Trim();
+                if (string.Equals("--", remainder, StringComparison.Ordinal))
+                {
+                    FinalBoundaryFound = true;
+                }
+                Debug.Assert(FinalBoundaryFound || string.Equals(string.Empty, remainder, StringComparison.Ordinal), "Un-expected data found on the boundary line: " + remainder);
+
+                _finished = true;
+                return 0;
+            }
+
+            // No possible boundary match within the buffered data, return the data from the buffer.
+            read = _innerStream.Read(buffer, offset, Math.Min(count, bufferedData.Count));
+            return UpdatePosition(read);
+        }
+
+        // Does Segment1 contain all of segment2, or does it end with the start of segment2?
+        // 1: AAAAABBBBBCCCCC
+        // 2:      BBBBB
+        // Or:
+        // 1: AAAAABBB
+        // 2:      BBBBB
+        private static bool SubMatch(ArraySegment<byte> segment1, byte[] matchBytes, out int matchOffset, out int matchCount)
+        {
+            matchCount = 0;
+            for (matchOffset = segment1.Offset; matchOffset < segment1.Offset + segment1.Count; matchOffset++)
+            {
+                int countLimit = segment1.Offset - matchOffset + segment1.Count;
+                for (matchCount = 0; matchCount < matchBytes.Length && matchCount < countLimit; matchCount++)
+                {
+                    if (matchBytes[matchCount] != segment1.Array[matchOffset + matchCount])
+                    {
+                        matchCount = 0;
+                        break;
+                    }
+                }
+                if (matchCount > 0)
+                {
+                    break;
+                }
+            }
+            return matchCount > 0;
+        }
+    }
+}

src/Microsoft.AspNet.WebUtilities/MultipartSection.cs

@@ -0,0 +1,47 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+using System.IO;
+
+namespace Microsoft.AspNet.WebUtilities
+{
+    public class MultipartSection
+    {
+        public string ContentType
+        {
+            get
+            {
+                string[] values;
+                if (Headers.TryGetValue("Content-Type", out values))
+                {
+                    return string.Join(", ", values);
+                }
+                return null;
+            }
+        }
+
+        public string ContentDisposition
+        {
+            get
+            {
+                string[] values;
+                if (Headers.TryGetValue("Content-Disposition", out values))
+                {
+                    return string.Join(", ", values);
+                }
+                return null;
+            }
+        }
+
+        public IDictionary<string, string[]> Headers { get; set; }
+
+        public Stream Body { get; set; }
+
+        /// <summary>
+        /// The position where the body starts in the total multipart body.
+        /// This may not be available if the total multipart body is not seekable.
+        /// </summary>
+        public long? BaseStreamOffset { get; set; }
+    }
+}

src/Microsoft.AspNet.WebUtilities/ParsingHelpers.cs

@@ -1,111 +0,0 @@
-// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
-// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
-
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using Microsoft.AspNet.Http;
-using Microsoft.AspNet.WebUtilities.Collections;
-
-namespace Microsoft.AspNet.WebUtilities
-{
-    internal static class ParsingHelpers
-    {
-        internal static void ParseDelimited(string text, char[] delimiters, Action<string, string, object> callback, object state)
-        {
-            int textLength = text.Length;
-            int equalIndex = text.IndexOf('=');
-            if (equalIndex == -1)
-            {
-                equalIndex = textLength;
-            }
-            int scanIndex = 0;
-            while (scanIndex < textLength)
-            {
-                int delimiterIndex = text.IndexOfAny(delimiters, scanIndex);
-                if (delimiterIndex == -1)
-                {
-                    delimiterIndex = textLength;
-                }
-                if (equalIndex < delimiterIndex)
-                {
-                    while (scanIndex != equalIndex && char.IsWhiteSpace(text[scanIndex]))
-                    {
-                        ++scanIndex;
-                    }
-                    string name = text.Substring(scanIndex, equalIndex - scanIndex);
-                    string value = text.Substring(equalIndex + 1, delimiterIndex - equalIndex - 1);
-                    callback(
-                        Uri.UnescapeDataString(name.Replace('+', ' ')),
-                        Uri.UnescapeDataString(value.Replace('+', ' ')),
-                        state);
-                    equalIndex = text.IndexOf('=', delimiterIndex);
-                    if (equalIndex == -1)
-                    {
-                        equalIndex = textLength;
-                    }
-                }
-                scanIndex = delimiterIndex + 1;
-            }
-        }
-
-        private static readonly Action<string, string, object> AppendItemCallback = (name, value, state) =>
-        {
-            var dictionary = (IDictionary<string, List<String>>)state;
-
-            List<string> existing;
-            if (!dictionary.TryGetValue(name, out existing))
-            {
-                dictionary.Add(name, new List<string>(1) { value });
-            }
-            else
-            {
-                existing.Add(value);
-            }
-        };
-
-        internal static IFormCollection GetForm(string text)
-        {
-            IDictionary<string, string[]> form = new Dictionary<string, string[]>(StringComparer.OrdinalIgnoreCase);
-            var accumulator = new Dictionary<string, List<string>>(StringComparer.OrdinalIgnoreCase);
-            ParseDelimited(text, Ampersand, AppendItemCallback, accumulator);
-            foreach (var kv in accumulator)
-            {
-                form.Add(kv.Key, kv.Value.ToArray());
-            }
-            return new FormCollection(form);
-        }
-
-        internal static string GetJoinedValue(IDictionary<string, string[]> store, string key)
-        {
-            string[] values = GetUnmodifiedValues(store, key);
-            return values == null ? null : string.Join(",", values);
-        }
-
-        internal static string[] GetUnmodifiedValues(IDictionary<string, string[]> store, string key)
-        {
-            if (store == null)
-            {
-                throw new ArgumentNullException("store");
-            }
-            string[] values;
-            return store.TryGetValue(key, out values) ? values : null;
-        }
-
-        private static readonly char[] Ampersand = new[] { '&' };
-
-        internal static IReadableStringCollection GetQuery(string queryString)
-        {
-            if (!string.IsNullOrEmpty(queryString) && queryString[0] == '?')
-            {
-                queryString = queryString.Substring(1);
-            }
-            var accumulator = new Dictionary<string, List<string>>(StringComparer.OrdinalIgnoreCase);
-            ParseDelimited(queryString, Ampersand, AppendItemCallback, accumulator);
-            return new ReadableStringCollection(accumulator.ToDictionary(
-                    item => item.Key,
-                    item => item.Value.ToArray(),
-                    StringComparer.OrdinalIgnoreCase));
-        }
-    }
-}

src/Microsoft.AspNet.WebUtilities/QueryHelpers.cs

@@ -4,7 +4,6 @@
 using System;
 using System.Collections.Generic;
 using System.Text;
-using Microsoft.AspNet.Http;
 
 namespace Microsoft.AspNet.WebUtilities
 {
@@ -50,9 +49,49 @@ namespace Microsoft.AspNet.WebUtilities
         /// </summary>
         /// <param name="text">The raw query string value, with or without the leading '?'.</param>
         /// <returns>A collection of parsed keys and values.</returns>
-        public static IReadableStringCollection ParseQuery(string text)
+        public static IDictionary<string, string[]> ParseQuery(string queryString)
         {
-            return ParsingHelpers.GetQuery(text);
+            if (!string.IsNullOrEmpty(queryString) && queryString[0] == '?')
+            {
+                queryString = queryString.Substring(1);
+            }
+            var accumulator = new KeyValueAccumulator<string, string>(StringComparer.OrdinalIgnoreCase);
+
+            int textLength = queryString.Length;
+            int equalIndex = queryString.IndexOf('=');
+            if (equalIndex == -1)
+            {
+                equalIndex = textLength;
+            }
+            int scanIndex = 0;
+            while (scanIndex < textLength)
+            {
+                int delimiterIndex = queryString.IndexOf('&', scanIndex);
+                if (delimiterIndex == -1)
+                {
+                    delimiterIndex = textLength;
+                }
+                if (equalIndex < delimiterIndex)
+                {
+                    while (scanIndex != equalIndex && char.IsWhiteSpace(queryString[scanIndex]))
+                    {
+                        ++scanIndex;
+                    }
+                    string name = queryString.Substring(scanIndex, equalIndex - scanIndex);
+                    string value = queryString.Substring(equalIndex + 1, delimiterIndex - equalIndex - 1);
+                    accumulator.Append(
+                        Uri.UnescapeDataString(name.Replace('+', ' ')),
+                        Uri.UnescapeDataString(value.Replace('+', ' ')));
+                    equalIndex = queryString.IndexOf('=', delimiterIndex);
+                    if (equalIndex == -1)
+                    {
+                        equalIndex = textLength;
+                    }
+                }
+                scanIndex = delimiterIndex + 1;
+            }
+
+            return accumulator.GetResults();
         }
     }
 }

src/Microsoft.AspNet.WebUtilities/StreamHelperExtensions.cs

@@ -0,0 +1,23 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.AspNet.WebUtilities
+{
+    public static class StreamHelperExtensions
+    {
+        public static async Task DrainAsync(this Stream stream, CancellationToken cancellationToken)
+        {
+            byte[] buffer = new byte[1024];
+            cancellationToken.ThrowIfCancellationRequested();
+            while (await stream.ReadAsync(buffer, 0, buffer.Length, cancellationToken) > 0)
+            {
+                // Not all streams support cancellation directly.
+                cancellationToken.ThrowIfCancellationRequested();
+            }
+        }
+    }
+}

src/Microsoft.AspNet.WebUtilities/project.json

@@ -9,6 +9,7 @@
         "aspnetcore50": {
             "dependencies": {
                 "System.Diagnostics.Debug": "4.0.10-beta-*",
+                "System.IO.FileSystem": "4.0.0-beta-*",
                 "System.Runtime": "4.0.20-beta-*"
             }
         }

test/Microsoft.AspNet.PipelineCore.Tests/FormFeatureTests.cs

@@ -1,72 +1,266 @@
 // Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
 using System.IO;
+using System.Linq;
 using System.Text;
-using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.AspNet.FeatureModel;
-using Microsoft.AspNet.HttpFeature;
-using Moq;
+using Microsoft.AspNet.WebUtilities;
 using Xunit;
 
-namespace Microsoft.AspNet.PipelineCore.Tests
+namespace Microsoft.AspNet.PipelineCore
 {
     public class FormFeatureTests
     {
         [Fact]
-        public async Task GetFormAsync_ReturnsParsedFormCollection()
+        public async Task ReadFormAsync_SimpleData_ReturnsParsedFormCollection()
         {
             // Arrange
             var formContent = Encoding.UTF8.GetBytes("foo=bar&baz=2");
-            var features = new Mock<IFeatureCollection>();
-            var request = new Mock<IHttpRequestFeature>();
-            request.SetupGet(r => r.Body).Returns(new MemoryStream(formContent));
+            var context = new DefaultHttpContext();
+            context.Request.ContentType = "application/x-www-form-urlencoded; charset=utf-8";
+            context.Request.Body = new MemoryStream(formContent);
 
-            object value = request.Object;
-            features.Setup(f => f.TryGetValue(typeof(IHttpRequestFeature), out value))
-                    .Returns(true);
-
-            var provider = new FormFeature(features.Object);
+            // Not cached yet
+            var formFeature = context.GetFeature<IFormFeature>();
+            Assert.Null(formFeature);
 
             // Act
-            var formCollection = await provider.GetFormAsync(CancellationToken.None);
+            var formCollection = await context.Request.ReadFormAsync();
 
             // Assert
             Assert.Equal("bar", formCollection["foo"]);
             Assert.Equal("2", formCollection["baz"]);
+
+            // Cached
+            formFeature = context.GetFeature<IFormFeature>();
+            Assert.NotNull(formFeature);
+            Assert.NotNull(formFeature.Form);
+            Assert.Same(formFeature.Form, formCollection);
         }
 
         [Fact]
-        public async Task GetFormAsync_CachesFormCollectionPerBodyStream()
+        public async Task ReadFormAsync_EmptyKeyAtEndAllowed()
         {
             // Arrange
-            var formContent1 = Encoding.UTF8.GetBytes("foo=bar&baz=2");
-            var formContent2 = Encoding.UTF8.GetBytes("collection2=value");
-            var features = new Mock<IFeatureCollection>();
-            var request = new Mock<IHttpRequestFeature>();
-            request.SetupGet(r => r.Body).Returns(new MemoryStream(formContent1));
+            var formContent = Encoding.UTF8.GetBytes("=bar");
+            var body = new MemoryStream(formContent);
 
-            object value = request.Object;
-            features.Setup(f => f.TryGetValue(typeof(IHttpRequestFeature), out value))
-                    .Returns(true);
+            var formCollection = await FormReader.ReadFormAsync(body);
 
-            var provider = new FormFeature(features.Object);
+            // Assert
+            Assert.Equal("bar", formCollection[""].FirstOrDefault());
+        }
 
-            // Act - 1
-            var formCollection = await provider.GetFormAsync(CancellationToken.None);
+        [Fact]
+        public async Task ReadFormAsync_EmptyKeyWithAdditionalEntryAllowed()
+        {
+            // Arrange
+            var formContent = Encoding.UTF8.GetBytes("=bar&baz=2");
+            var body = new MemoryStream(formContent);
 
-            // Assert - 1
-            Assert.Equal("bar", formCollection["foo"]);
-            Assert.Equal("2", formCollection["baz"]);
-            Assert.Same(formCollection, await provider.GetFormAsync(CancellationToken.None));
+            var formCollection = await FormReader.ReadFormAsync(body);
 
-            // Act - 2
-            request.SetupGet(r => r.Body).Returns(new MemoryStream(formContent2));
-            formCollection = await provider.GetFormAsync(CancellationToken.None);
+            // Assert
+            Assert.Equal("bar", formCollection[""].FirstOrDefault());
+            Assert.Equal("2", formCollection["baz"].FirstOrDefault());
+        }
 
-            // Assert - 2
-            Assert.Equal("value", formCollection["collection2"]);
+        [Fact]
+        public async Task ReadFormAsync_EmptyValuedAtEndAllowed()
+        {
+            // Arrange
+            var formContent = Encoding.UTF8.GetBytes("foo=");
+            var body = new MemoryStream(formContent);
+
+            var formCollection = await FormReader.ReadFormAsync(body);
+
+            // Assert
+            Assert.Equal("", formCollection["foo"].FirstOrDefault());
+        }
+
+        [Fact]
+        public async Task ReadFormAsync_EmptyValuedWithAdditionalEntryAllowed()
+        {
+            // Arrange
+            var formContent = Encoding.UTF8.GetBytes("foo=&baz=2");
+            var body = new MemoryStream(formContent);
+
+            var formCollection = await FormReader.ReadFormAsync(body);
+
+            // Assert
+            Assert.Equal("", formCollection["foo"].FirstOrDefault());
+            Assert.Equal("2", formCollection["baz"].FirstOrDefault());
+        }
+
+        private const string MultipartContentType = "multipart/form-data; boundary=WebKitFormBoundary5pDRpGheQXaM8k3T";
+        private const string EmptyMultipartForm =
+@"--WebKitFormBoundary5pDRpGheQXaM8k3T--";
+        private const string MultipartFormWithField =
+@"--WebKitFormBoundary5pDRpGheQXaM8k3T
+Content-Disposition: form-data; name=""description""
+
+Foo
+--WebKitFormBoundary5pDRpGheQXaM8k3T--";
+        private const string MultipartFormWithFile =
+@"--WebKitFormBoundary5pDRpGheQXaM8k3T
+Content-Disposition: form-data; name=""myfile1""; filename=""temp.html""
+Content-Type: text/html
+
+<html><body>Hello World</body></html>
+--WebKitFormBoundary5pDRpGheQXaM8k3T--";
+        private const string MultipartFormWithFieldAndFile =
+@"--WebKitFormBoundary5pDRpGheQXaM8k3T
+Content-Disposition: form-data; name=""description""
+
+Foo
+--WebKitFormBoundary5pDRpGheQXaM8k3T
+Content-Disposition: form-data; name=""myfile1""; filename=""temp.html""
+Content-Type: text/html
+
+<html><body>Hello World</body></html>
+--WebKitFormBoundary5pDRpGheQXaM8k3T--";
+
+        [Fact]
+        public async Task ReadForm_EmptyMultipart_ReturnsParsedFormCollection()
+        {
+            var formContent = Encoding.UTF8.GetBytes(EmptyMultipartForm);
+            var context = new DefaultHttpContext();
+            context.Request.ContentType = MultipartContentType;
+            context.Request.Body = new MemoryStream(formContent);
+
+            // Not cached yet
+            var formFeature = context.GetFeature<IFormFeature>();
+            Assert.Null(formFeature);
+
+            var formCollection = context.Request.Form;
+
+            Assert.NotNull(formCollection);
+
+            // Cached
+            formFeature = context.GetFeature<IFormFeature>();
+            Assert.NotNull(formFeature);
+            Assert.NotNull(formFeature.Form);
+            Assert.Same(formCollection, formFeature.Form);
+            Assert.Same(formCollection, await context.Request.ReadFormAsync());
+
+            // Content
+            Assert.Equal(0, formCollection.Count);
+            Assert.NotNull(formCollection.Files);
+            Assert.Equal(0, formCollection.Files.Count);
+        }
+
+        [Fact]
+        public async Task ReadForm_MultipartWithField_ReturnsParsedFormCollection()
+        {
+            var formContent = Encoding.UTF8.GetBytes(MultipartFormWithField);
+            var context = new DefaultHttpContext();
+            context.Request.ContentType = MultipartContentType;
+            context.Request.Body = new MemoryStream(formContent);
+
+            // Not cached yet
+            var formFeature = context.GetFeature<IFormFeature>();
+            Assert.Null(formFeature);
+
+            var formCollection = context.Request.Form;
+
+            Assert.NotNull(formCollection);
+
+            // Cached
+            formFeature = context.GetFeature<IFormFeature>();
+            Assert.NotNull(formFeature);
+            Assert.NotNull(formFeature.Form);
+            Assert.Same(formCollection, formFeature.Form);
+            Assert.Same(formCollection, await context.Request.ReadFormAsync());
+
+            // Content
+            Assert.Equal(1, formCollection.Count);
+            Assert.Equal("Foo", formCollection["description"]);
+
+            Assert.NotNull(formCollection.Files);
+            Assert.Equal(0, formCollection.Files.Count);
+        }
+
+        [Fact]
+        public async Task ReadFormAsync_MultipartWithFile_ReturnsParsedFormCollection()
+        {
+            var formContent = Encoding.UTF8.GetBytes(MultipartFormWithFile);
+            var context = new DefaultHttpContext();
+            context.Request.ContentType = MultipartContentType;
+            context.Request.Body = new MemoryStream(formContent);
+
+            // Not cached yet
+            var formFeature = context.GetFeature<IFormFeature>();
+            Assert.Null(formFeature);
+
+            var formCollection = await context.Request.ReadFormAsync();
+
+            Assert.NotNull(formCollection);
+
+            // Cached
+            formFeature = context.GetFeature<IFormFeature>();
+            Assert.NotNull(formFeature);
+            Assert.NotNull(formFeature.Form);
+            Assert.Same(formFeature.Form, formCollection);
+            Assert.Same(formCollection, context.Request.Form);
+
+            // Content
+            Assert.Equal(0, formCollection.Count);
+
+            Assert.NotNull(formCollection.Files);
+            Assert.Equal(1, formCollection.Files.Count);
+
+            var file = formCollection.Files["myfile1"];
+            Assert.Equal("text/html", file.ContentType);
+            Assert.Equal(@"form-data; name=""myfile1""; filename=""temp.html""", file.ContentDisposition);
+            var body = file.OpenReadStream();
+            using (var reader = new StreamReader(body))
+            {
+                var content = reader.ReadToEnd();
+                Assert.Equal(content, "<html><body>Hello World</body></html>");
+            }
+        }
+
+        [Fact]
+        public async Task ReadFormAsync_MultipartWithFieldAndFile_ReturnsParsedFormCollection()
+        {
+            var formContent = Encoding.UTF8.GetBytes(MultipartFormWithFieldAndFile);
+            var context = new DefaultHttpContext();
+            context.Request.ContentType = MultipartContentType;
+            context.Request.Body = new MemoryStream(formContent);
+
+            // Not cached yet
+            var formFeature = context.GetFeature<IFormFeature>();
+            Assert.Null(formFeature);
+
+            var formCollection = await context.Request.ReadFormAsync();
+
+            Assert.NotNull(formCollection);
+
+            // Cached
+            formFeature = context.GetFeature<IFormFeature>();
+            Assert.NotNull(formFeature);
+            Assert.NotNull(formFeature.Form);
+            Assert.Same(formFeature.Form, formCollection);
+            Assert.Same(formCollection, context.Request.Form);
+
+            // Content
+            Assert.Equal(1, formCollection.Count);
+            Assert.Equal("Foo", formCollection["description"]);
+
+            Assert.NotNull(formCollection.Files);
+            Assert.Equal(1, formCollection.Files.Count);
+
+            var file = formCollection.Files["myfile1"];
+            Assert.Equal("text/html", file.ContentType);
+            Assert.Equal(@"form-data; name=""myfile1""; filename=""temp.html""", file.ContentDisposition);
+            var body = file.OpenReadStream();
+            using (var reader = new StreamReader(body))
+            {
+                var content = reader.ReadToEnd();
+                Assert.Equal(content, "<html><body>Hello World</body></html>");
+            }
         }
     }
 }

test/Microsoft.AspNet.WebUtilities.Tests/MultipartReaderTests.cs

@@ -0,0 +1,185 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.IO;
+using System.Text;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace Microsoft.AspNet.WebUtilities
+{
+    public class MultipartReaderTests
+    {
+        private const string Boundary = "9051914041544843365972754266";
+        private const string OnePartBody =
+@"--9051914041544843365972754266
+Content-Disposition: form-data; name=""text""
+
+text default
+--9051914041544843365972754266--
+";
+        private const string OnePartBodyWithTrailingWhitespace =
+@"--9051914041544843365972754266             
+Content-Disposition: form-data; name=""text""
+
+text default
+--9051914041544843365972754266--
+";
+        // It's non-compliant but common to leave off the last CRLF.
+        private const string OnePartBodyWithoutFinalCRLF =
+@"--9051914041544843365972754266
+Content-Disposition: form-data; name=""text""
+
+text default
+--9051914041544843365972754266--";
+        private const string TwoPartBody =
+@"--9051914041544843365972754266
+Content-Disposition: form-data; name=""text""
+
+text default
+--9051914041544843365972754266
+Content-Disposition: form-data; name=""file1""; filename=""a.txt""
+Content-Type: text/plain
+
+Content of a.txt.
+
+--9051914041544843365972754266--
+";
+        private const string ThreePartBody =
+@"--9051914041544843365972754266
+Content-Disposition: form-data; name=""text""
+
+text default
+--9051914041544843365972754266
+Content-Disposition: form-data; name=""file1""; filename=""a.txt""
+Content-Type: text/plain
+
+Content of a.txt.
+
+--9051914041544843365972754266
+Content-Disposition: form-data; name=""file2""; filename=""a.html""
+Content-Type: text/html
+
+<!DOCTYPE html><title>Content of a.html.</title>
+
+--9051914041544843365972754266--
+";
+
+        private static MemoryStream MakeStream(string text)
+        {
+            return new MemoryStream(Encoding.UTF8.GetBytes(text));
+        }
+
+        [Fact]
+        public async Task MutipartReader_ReadSinglePartBody_Success()
+        {
+            var stream = MakeStream(OnePartBody);
+            var reader = new MultipartReader(Boundary, stream);
+
+            var section = await reader.ReadNextSectionAsync();
+            Assert.NotNull(section);
+            Assert.Equal(1, section.Headers.Count);
+            Assert.Equal("form-data; name=\"text\"", section.Headers["Content-Disposition"][0]);
+            var buffer = new MemoryStream();
+            await section.Body.CopyToAsync(buffer);
+            Assert.Equal("text default", Encoding.ASCII.GetString(buffer.ToArray()));
+
+            Assert.Null(await reader.ReadNextSectionAsync());
+        }
+
+        [Fact]
+        public async Task MutipartReader_ReadSinglePartBodyWithTrailingWhitespace_Success()
+        {
+            var stream = MakeStream(OnePartBodyWithTrailingWhitespace);
+            var reader = new MultipartReader(Boundary, stream);
+
+            var section = await reader.ReadNextSectionAsync();
+            Assert.NotNull(section);
+            Assert.Equal(1, section.Headers.Count);
+            Assert.Equal("form-data; name=\"text\"", section.Headers["Content-Disposition"][0]);
+            var buffer = new MemoryStream();
+            await section.Body.CopyToAsync(buffer);
+            Assert.Equal("text default", Encoding.ASCII.GetString(buffer.ToArray()));
+
+            Assert.Null(await reader.ReadNextSectionAsync());
+        }
+
+        [Fact]
+        public async Task MutipartReader_ReadSinglePartBodyWithoutLastCRLF_Success()
+        {
+            var stream = MakeStream(OnePartBodyWithoutFinalCRLF);
+            var reader = new MultipartReader(Boundary, stream);
+
+            var section = await reader.ReadNextSectionAsync();
+            Assert.NotNull(section);
+            Assert.Equal(1, section.Headers.Count);
+            Assert.Equal("form-data; name=\"text\"", section.Headers["Content-Disposition"][0]);
+            var buffer = new MemoryStream();
+            await section.Body.CopyToAsync(buffer);
+            Assert.Equal("text default", Encoding.ASCII.GetString(buffer.ToArray()));
+
+            Assert.Null(await reader.ReadNextSectionAsync());
+        }
+
+        [Fact]
+        public async Task MutipartReader_ReadTwoPartBody_Success()
+        {
+            var stream = MakeStream(TwoPartBody);
+            var reader = new MultipartReader(Boundary, stream);
+
+            var section = await reader.ReadNextSectionAsync();
+            Assert.NotNull(section);
+            Assert.Equal(1, section.Headers.Count);
+            Assert.Equal("form-data; name=\"text\"", section.Headers["Content-Disposition"][0]);
+            var buffer = new MemoryStream();
+            await section.Body.CopyToAsync(buffer);
+            Assert.Equal("text default", Encoding.ASCII.GetString(buffer.ToArray()));
+
+            section = await reader.ReadNextSectionAsync();
+            Assert.NotNull(section);
+            Assert.Equal(2, section.Headers.Count);
+            Assert.Equal("form-data; name=\"file1\"; filename=\"a.txt\"", section.Headers["Content-Disposition"][0]);
+            Assert.Equal("text/plain", section.Headers["Content-Type"][0]);
+            buffer = new MemoryStream();
+            await section.Body.CopyToAsync(buffer);
+            Assert.Equal("Content of a.txt.\r\n", Encoding.ASCII.GetString(buffer.ToArray()));
+
+            Assert.Null(await reader.ReadNextSectionAsync());
+        }
+
+        [Fact]
+        public async Task MutipartReader_ThreePartBody_Success()
+        {
+            var stream = MakeStream(ThreePartBody);
+            var reader = new MultipartReader(Boundary, stream);
+
+            var section = await reader.ReadNextSectionAsync();
+            Assert.NotNull(section);
+            Assert.Equal(1, section.Headers.Count);
+            Assert.Equal("form-data; name=\"text\"", section.Headers["Content-Disposition"][0]);
+            var buffer = new MemoryStream();
+            await section.Body.CopyToAsync(buffer);
+            Assert.Equal("text default", Encoding.ASCII.GetString(buffer.ToArray()));
+
+            section = await reader.ReadNextSectionAsync();
+            Assert.NotNull(section);
+            Assert.Equal(2, section.Headers.Count);
+            Assert.Equal("form-data; name=\"file1\"; filename=\"a.txt\"", section.Headers["Content-Disposition"][0]);
+            Assert.Equal("text/plain", section.Headers["Content-Type"][0]);
+            buffer = new MemoryStream();
+            await section.Body.CopyToAsync(buffer);
+            Assert.Equal("Content of a.txt.\r\n", Encoding.ASCII.GetString(buffer.ToArray()));
+
+            section = await reader.ReadNextSectionAsync();
+            Assert.NotNull(section);
+            Assert.Equal(2, section.Headers.Count);
+            Assert.Equal("form-data; name=\"file2\"; filename=\"a.html\"", section.Headers["Content-Disposition"][0]);
+            Assert.Equal("text/html", section.Headers["Content-Type"][0]);
+            buffer = new MemoryStream();
+            await section.Body.CopyToAsync(buffer);
+            Assert.Equal("<!DOCTYPE html><title>Content of a.html.</title>\r\n", Encoding.ASCII.GetString(buffer.ToArray()));
+
+            Assert.Null(await reader.ReadNextSectionAsync());
+        }
+    }
+}

test/Microsoft.AspNet.WebUtilities.Tests/QueryHelpersTests.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Linq;
 using Xunit;
 
 namespace Microsoft.AspNet.WebUtilities
@@ -13,8 +14,8 @@ namespace Microsoft.AspNet.WebUtilities
         {
             var collection = QueryHelpers.ParseQuery("?key1=value1&key2=value2");
             Assert.Equal(2, collection.Count);
-            Assert.Equal("value1", collection["key1"]);
-            Assert.Equal("value2", collection["key2"]);
+            Assert.Equal("value1", collection["key1"].FirstOrDefault());
+            Assert.Equal("value2", collection["key2"].FirstOrDefault());
         }
 
         [Fact]
@@ -22,8 +23,8 @@ namespace Microsoft.AspNet.WebUtilities
         {
             var collection = QueryHelpers.ParseQuery("key1=value1&key2=value2");
             Assert.Equal(2, collection.Count);
-            Assert.Equal("value1", collection["key1"]);
-            Assert.Equal("value2", collection["key2"]);
+            Assert.Equal("value1", collection["key1"].FirstOrDefault());
+            Assert.Equal("value2", collection["key2"].FirstOrDefault());
         }
 
         [Fact]
@@ -31,8 +32,8 @@ namespace Microsoft.AspNet.WebUtilities
         {
             var collection = QueryHelpers.ParseQuery("?key1=valueA&key2=valueB&key1=valueC");
             Assert.Equal(2, collection.Count);
-            Assert.Equal("valueA,valueC", collection["key1"]);
-            Assert.Equal("valueB", collection["key2"]);
+            Assert.Equal(new[] { "valueA", "valueC" }, collection["key1"]);
+            Assert.Equal("valueB", collection["key2"].FirstOrDefault());
         }
 
         [Fact]
@@ -40,8 +41,8 @@ namespace Microsoft.AspNet.WebUtilities
         {
             var collection = QueryHelpers.ParseQuery("?key1=&key2=");
             Assert.Equal(2, collection.Count);
-            Assert.Equal(string.Empty, collection["key1"]);
-            Assert.Equal(string.Empty, collection["key2"]);
+            Assert.Equal(string.Empty, collection["key1"].FirstOrDefault());
+            Assert.Equal(string.Empty, collection["key2"].FirstOrDefault());
         }
 
         [Fact]
@@ -49,7 +50,7 @@ namespace Microsoft.AspNet.WebUtilities
         {
             var collection = QueryHelpers.ParseQuery("?=value1&=");
             Assert.Equal(1, collection.Count);
-            Assert.Equal("value1,", collection[""]);
+            Assert.Equal(new[] { "value1", "" }, collection[""]);
         }
     }
 }