Move Microsoft.Extensions.WebEncoders to HtmlAbstractions

HtmlAbstractions.sln

@@ -1,6 +1,6 @@
 Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio 14
-VisualStudioVersion = 14.0.24720.0
+VisualStudioVersion = 14.0.24711.0
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "src", "src", "{A5A15F1C-885A-452A-A731-B0173DDBD913}"
 EndProject
@@ -16,6 +16,10 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
 		NuGetPackageVerifier.json = NuGetPackageVerifier.json
 	EndProjectSection
 EndProject
+Project("{8BB2217D-0F2D-49D1-97BC-3654ED321F3B}") = "Microsoft.Extensions.WebEncoders", "src\Microsoft.Extensions.WebEncoders\Microsoft.Extensions.WebEncoders.xproj", "{DD2CE416-765E-4000-A03E-C2FF165DA1B6}"
+EndProject
+Project("{8BB2217D-0F2D-49D1-97BC-3654ED321F3B}") = "Microsoft.Extensions.WebEncoders.Tests", "test\Microsoft.Extensions.WebEncoders.Tests\Microsoft.Extensions.WebEncoders.Tests.xproj", "{7AE2731D-43CD-4CF8-850A-4914DE2CE930}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -50,6 +54,30 @@ Global
 		{2D187B88-94BD-4A39-AC97-F8F8B9363301}.Release|Mixed Platforms.Build.0 = Release|Any CPU
 		{2D187B88-94BD-4A39-AC97-F8F8B9363301}.Release|x86.ActiveCfg = Release|Any CPU
 		{2D187B88-94BD-4A39-AC97-F8F8B9363301}.Release|x86.Build.0 = Release|Any CPU
+		{DD2CE416-765E-4000-A03E-C2FF165DA1B6}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{DD2CE416-765E-4000-A03E-C2FF165DA1B6}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{DD2CE416-765E-4000-A03E-C2FF165DA1B6}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
+		{DD2CE416-765E-4000-A03E-C2FF165DA1B6}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU
+		{DD2CE416-765E-4000-A03E-C2FF165DA1B6}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{DD2CE416-765E-4000-A03E-C2FF165DA1B6}.Debug|x86.Build.0 = Debug|Any CPU
+		{DD2CE416-765E-4000-A03E-C2FF165DA1B6}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{DD2CE416-765E-4000-A03E-C2FF165DA1B6}.Release|Any CPU.Build.0 = Release|Any CPU
+		{DD2CE416-765E-4000-A03E-C2FF165DA1B6}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
+		{DD2CE416-765E-4000-A03E-C2FF165DA1B6}.Release|Mixed Platforms.Build.0 = Release|Any CPU
+		{DD2CE416-765E-4000-A03E-C2FF165DA1B6}.Release|x86.ActiveCfg = Release|Any CPU
+		{DD2CE416-765E-4000-A03E-C2FF165DA1B6}.Release|x86.Build.0 = Release|Any CPU
+		{7AE2731D-43CD-4CF8-850A-4914DE2CE930}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{7AE2731D-43CD-4CF8-850A-4914DE2CE930}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{7AE2731D-43CD-4CF8-850A-4914DE2CE930}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
+		{7AE2731D-43CD-4CF8-850A-4914DE2CE930}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU
+		{7AE2731D-43CD-4CF8-850A-4914DE2CE930}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{7AE2731D-43CD-4CF8-850A-4914DE2CE930}.Debug|x86.Build.0 = Debug|Any CPU
+		{7AE2731D-43CD-4CF8-850A-4914DE2CE930}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{7AE2731D-43CD-4CF8-850A-4914DE2CE930}.Release|Any CPU.Build.0 = Release|Any CPU
+		{7AE2731D-43CD-4CF8-850A-4914DE2CE930}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
+		{7AE2731D-43CD-4CF8-850A-4914DE2CE930}.Release|Mixed Platforms.Build.0 = Release|Any CPU
+		{7AE2731D-43CD-4CF8-850A-4914DE2CE930}.Release|x86.ActiveCfg = Release|Any CPU
+		{7AE2731D-43CD-4CF8-850A-4914DE2CE930}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -57,5 +85,7 @@ Global
 	GlobalSection(NestedProjects) = preSolution
 		{68A28E4A-3ADE-4187-9625-4FF185887CB3} = {A5A15F1C-885A-452A-A731-B0173DDBD913}
 		{2D187B88-94BD-4A39-AC97-F8F8B9363301} = {F31FF137-390C-49BF-A3BD-7C6ED3597C21}
+		{DD2CE416-765E-4000-A03E-C2FF165DA1B6} = {A5A15F1C-885A-452A-A731-B0173DDBD913}
+		{7AE2731D-43CD-4CF8-850A-4914DE2CE930} = {F31FF137-390C-49BF-A3BD-7C6ED3597C21}
 	EndGlobalSection
 EndGlobal

NuGetPackageVerifier.json

@@ -9,7 +9,8 @@
             "StrictSemanticVersionValidationRule"
         ],
         "packages": {
-            "Microsoft.AspNet.Html.Abstractions": { }
+            "Microsoft.AspNet.Html.Abstractions": { },
+            "Microsoft.Extensions.WebEncoders": { }
         }
     },
     "Default": { // Rules to run for packages not listed in any other set.

src/Microsoft.Extensions.WebEncoders/EncoderServiceCollectionExtensions.cs

@@ -0,0 +1,64 @@
+// Copyright (c) .NET Foundation. 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.Text.Encodings.Web;
+using Microsoft.Extensions.DependencyInjection.Extensions;
+using Microsoft.Extensions.Options;
+using Microsoft.Extensions.WebEncoders;
+
+namespace Microsoft.Extensions.DependencyInjection
+{
+    public static class EncoderServiceCollectionExtensions
+    {
+        public static IServiceCollection AddWebEncoders(this IServiceCollection services)
+        {
+            if (services == null)
+            {
+                throw new ArgumentNullException(nameof(services));
+            }
+
+            return AddWebEncoders(services, configureOptions: null);
+        }
+
+        public static IServiceCollection AddWebEncoders(this IServiceCollection services, Action<WebEncoderOptions> configureOptions)
+        {
+            if (services == null)
+            {
+                throw new ArgumentNullException(nameof(services));
+            }
+
+            services.AddOptions();
+
+            // Register the default encoders
+            // We want to call the 'Default' property getters lazily since they perform static caching
+            services.TryAddSingleton(
+                CreateFactory(() => HtmlEncoder.Default, settings => HtmlEncoder.Create(settings)));
+            services.TryAddSingleton(
+                CreateFactory(() => JavaScriptEncoder.Default, settings => JavaScriptEncoder.Create(settings)));
+            services.TryAddSingleton(
+                CreateFactory(() => UrlEncoder.Default, settings => UrlEncoder.Create(settings)));
+
+            if (configureOptions != null)
+            {
+                services.Configure(configureOptions);
+            }
+
+            return services;
+        }
+
+        private static Func<IServiceProvider, TService> CreateFactory<TService>(
+            Func<TService> defaultFactory,
+            Func<TextEncoderSettings, TService> customSettingsFactory)
+        {
+            return serviceProvider =>
+            {
+                var settings = serviceProvider
+                    ?.GetService<IOptions<WebEncoderOptions>>()
+                    ?.Value
+                    ?.TextEncoderSettings;
+                return (settings != null) ? customSettingsFactory(settings) : defaultFactory();
+            };
+        }
+    }
+}

src/Microsoft.Extensions.WebEncoders/EncoderServiceProviderExtensions.cs

@@ -0,0 +1,50 @@
+// Copyright (c) .NET Foundation. 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.Text.Encodings.Web;
+
+namespace Microsoft.Extensions.WebEncoders
+{
+    /// <summary>
+    /// Contains extension methods for fetching encoders from an <see cref="IServiceProvider"/>.
+    /// </summary>
+    public static class EncoderServiceProviderExtensions
+    {
+        /// <summary>
+        /// Retrieves an <see cref="HtmlEncoder"/> from an <see cref="IServiceProvider"/>.
+        /// </summary>
+        /// <remarks>
+        /// This method is guaranteed never to return null.
+        /// It will return a default encoder instance if <paramref name="serviceProvider"/> does not contain one or is null.
+        /// </remarks>
+        public static HtmlEncoder GetHtmlEncoder(this IServiceProvider serviceProvider)
+        {
+            return (HtmlEncoder)serviceProvider?.GetService(typeof(HtmlEncoder)) ?? HtmlEncoder.Default;
+        }
+
+        /// <summary>
+        /// Retrieves an <see cref="JavaScriptEncoder"/> from an <see cref="IServiceProvider"/>.
+        /// </summary>
+        /// <remarks>
+        /// This method is guaranteed never to return null.
+        /// It will return a default encoder instance if <paramref name="serviceProvider"/> does not contain one or is null.
+        /// </remarks>
+        public static JavaScriptEncoder GetJavaScriptEncoder(this IServiceProvider serviceProvider)
+        {
+            return (JavaScriptEncoder)serviceProvider?.GetService(typeof(JavaScriptEncoder)) ?? JavaScriptEncoder.Default;
+        }
+
+        /// <summary>
+        /// Retrieves an <see cref="UrlEncoder"/> from an <see cref="IServiceProvider"/>.
+        /// </summary>
+        /// <remarks>
+        /// This method is guaranteed never to return null.
+        /// It will return a default encoder instance if <paramref name="serviceProvider"/> does not contain one or is null.
+        /// </remarks>
+        public static UrlEncoder GetUrlEncoder(this IServiceProvider serviceProvider)
+        {
+            return (UrlEncoder)serviceProvider?.GetService(typeof(UrlEncoder)) ?? UrlEncoder.Default;
+        }
+    }
+}

src/Microsoft.Extensions.WebEncoders/Microsoft.Extensions.WebEncoders.xproj

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <VisualStudioVersion Condition="'$(VisualStudioVersion)' == ''">14.0</VisualStudioVersion>
+    <VSToolsPath Condition="'$(VSToolsPath)' == ''">$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)</VSToolsPath>
+  </PropertyGroup>
+  <Import Project="$(VSToolsPath)\DNX\Microsoft.DNX.Props" Condition="'$(VSToolsPath)' != ''" />
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>dd2ce416-765e-4000-a03e-c2ff165da1b6</ProjectGuid>
+    <BaseIntermediateOutputPath Condition="'$(BaseIntermediateOutputPath)'=='' ">..\..\artifacts\obj\$(MSBuildProjectName)</BaseIntermediateOutputPath>
+    <OutputPath Condition="'$(OutputPath)'=='' ">..\..\artifacts\bin\$(MSBuildProjectName)\</OutputPath>
+  </PropertyGroup>
+  <PropertyGroup>
+    <SchemaVersion>2.0</SchemaVersion>
+  </PropertyGroup>
+  <Import Project="$(VSToolsPath)\DNX\Microsoft.DNX.targets" Condition="'$(VSToolsPath)' != ''" />
+</Project>

src/Microsoft.Extensions.WebEncoders/Properties/AssemblyInfo.cs

@@ -0,0 +1,8 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Reflection;
+using System.Resources;
+
+[assembly: AssemblyMetadata("Serviceable", "True")]
+[assembly: NeutralResourcesLanguage("en-us")]

src/Microsoft.Extensions.WebEncoders/Testing/HtmlTestEncoder.cs

@@ -0,0 +1,104 @@
+// Copyright (c) .NET Foundation. 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.Encodings.Web;
+
+namespace Microsoft.Extensions.WebEncoders.Testing
+{
+    /// <summary>
+    /// Encoder used for unit testing.
+    /// </summary>
+    public sealed class HtmlTestEncoder : HtmlEncoder
+    {
+        public override int MaxOutputCharactersPerInputCharacter
+        {
+            get { return 1; }
+        }
+
+        public override string Encode(string value)
+        {
+            if (value == null)
+            {
+                throw new ArgumentNullException(nameof(value));
+            }
+
+            if (value.Length == 0)
+            {
+                return string.Empty;
+            }
+
+            return $"HtmlEncode[[{value}]]";
+        }
+
+        public override void Encode(TextWriter output, char[] value, int startIndex, int characterCount)
+        {
+            if (output == null)
+            {
+                throw new ArgumentNullException(nameof(output));
+            }
+
+            if (value == null)
+            {
+                throw new ArgumentNullException(nameof(value));
+            }
+
+            if (characterCount == 0)
+            {
+                return;
+            }
+
+            output.Write("HtmlEncode[[");
+            output.Write(value, startIndex, characterCount);
+            output.Write("]]");
+        }
+
+        public override void Encode(TextWriter output, string value, int startIndex, int characterCount)
+        {
+            if (output == null)
+            {
+                throw new ArgumentNullException(nameof(output));
+            }
+
+            if (value == null)
+            {
+                throw new ArgumentNullException(nameof(value));
+            }
+
+            if (characterCount == 0)
+            {
+                return;
+            }
+
+            output.Write("HtmlEncode[[");
+            output.Write(value.Substring(startIndex, characterCount));
+            output.Write("]]");
+        }
+
+        public override bool WillEncode(int unicodeScalar)
+        {
+            return false;
+        }
+
+        public override unsafe int FindFirstCharacterToEncode(char* text, int textLength)
+        {
+            return -1;
+        }
+
+        public override unsafe bool TryEncodeUnicodeScalar(
+            int unicodeScalar,
+            char* buffer,
+            int bufferLength,
+            out int numberOfCharactersWritten)
+        {
+            if (buffer == null)
+            {
+                throw new ArgumentNullException(nameof(buffer));
+            }
+
+            numberOfCharactersWritten = 0;
+            return false;
+        }
+    }
+}

src/Microsoft.Extensions.WebEncoders/Testing/JavaScriptTestEncoder.cs

@@ -0,0 +1,104 @@
+// Copyright (c) .NET Foundation. 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.Encodings.Web;
+
+namespace Microsoft.Extensions.WebEncoders.Testing
+{
+    /// <summary>
+    /// Encoder used for unit testing.
+    /// </summary>
+    public class JavaScriptTestEncoder : JavaScriptEncoder
+    {
+        public override int MaxOutputCharactersPerInputCharacter
+        {
+            get { return 1; }
+        }
+
+        public override string Encode(string value)
+        {
+            if (value == null)
+            {
+                throw new ArgumentNullException(nameof(value));
+            }
+
+            if (value.Length == 0)
+            {
+                return string.Empty;
+            }
+
+            return $"JavaScriptEncode[[{value}]]";
+        }
+
+        public override void Encode(TextWriter output, char[] value, int startIndex, int characterCount)
+        {
+            if (output == null)
+            {
+                throw new ArgumentNullException(nameof(output));
+            }
+
+            if (value == null)
+            {
+                throw new ArgumentNullException(nameof(value));
+            }
+
+            if (characterCount == 0)
+            {
+                return;
+            }
+
+            output.Write("JavaScriptEncode[[");
+            output.Write(value, startIndex, characterCount);
+            output.Write("]]");
+        }
+
+        public override void Encode(TextWriter output, string value, int startIndex, int characterCount)
+        {
+            if (output == null)
+            {
+                throw new ArgumentNullException(nameof(output));
+            }
+
+            if (value == null)
+            {
+                throw new ArgumentNullException(nameof(value));
+            }
+
+            if (characterCount == 0)
+            {
+                return;
+            }
+
+            output.Write("JavaScriptEncode[[");
+            output.Write(value.Substring(startIndex, characterCount));
+            output.Write("]]");
+        }
+
+        public override bool WillEncode(int unicodeScalar)
+        {
+            return false;
+        }
+
+        public override unsafe int FindFirstCharacterToEncode(char* text, int textLength)
+        {
+            return -1;
+        }
+
+        public override unsafe bool TryEncodeUnicodeScalar(
+            int unicodeScalar,
+            char* buffer,
+            int bufferLength,
+            out int numberOfCharactersWritten)
+        {
+            if (buffer == null)
+            {
+                throw new ArgumentNullException(nameof(buffer));
+            }
+
+            numberOfCharactersWritten = 0;
+            return false;
+        }
+    }
+}

src/Microsoft.Extensions.WebEncoders/Testing/UrlTestEncoder.cs

@@ -0,0 +1,104 @@
+// Copyright (c) .NET Foundation. 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.Encodings.Web;
+
+namespace Microsoft.Extensions.WebEncoders.Testing
+{
+    /// <summary>
+    /// Encoder used for unit testing.
+    /// </summary>
+    public class UrlTestEncoder : UrlEncoder
+    {
+        public override int MaxOutputCharactersPerInputCharacter
+        {
+            get { return 1; }
+        }
+
+        public override string Encode(string value)
+        {
+            if (value == null)
+            {
+                throw new ArgumentNullException(nameof(value));
+            }
+
+            if (value.Length == 0)
+            {
+                return string.Empty;
+            }
+
+            return $"UrlEncode[[{value}]]";
+        }
+
+        public override void Encode(TextWriter output, char[] value, int startIndex, int characterCount)
+        {
+            if (output == null)
+            {
+                throw new ArgumentNullException(nameof(output));
+            }
+
+            if (value == null)
+            {
+                throw new ArgumentNullException(nameof(value));
+            }
+
+            if (characterCount == 0)
+            {
+                return;
+            }
+
+            output.Write("UrlEncode[[");
+            output.Write(value, startIndex, characterCount);
+            output.Write("]]");
+        }
+
+        public override void Encode(TextWriter output, string value, int startIndex, int characterCount)
+        {
+            if (output == null)
+            {
+                throw new ArgumentNullException(nameof(output));
+            }
+
+            if (value == null)
+            {
+                throw new ArgumentNullException(nameof(value));
+            }
+
+            if (characterCount == 0)
+            {
+                return;
+            }
+
+            output.Write("UrlEncode[[");
+            output.Write(value.Substring(startIndex, characterCount));
+            output.Write("]]");
+        }
+
+        public override bool WillEncode(int unicodeScalar)
+        {
+            return false;
+        }
+
+        public override unsafe int FindFirstCharacterToEncode(char* text, int textLength)
+        {
+            return -1;
+        }
+
+        public override unsafe bool TryEncodeUnicodeScalar(
+            int unicodeScalar,
+            char* buffer,
+            int bufferLength,
+            out int numberOfCharactersWritten)
+        {
+            if (buffer == null)
+            {
+                throw new ArgumentNullException(nameof(buffer));
+            }
+
+            numberOfCharactersWritten = 0;
+            return false;
+        }
+    }
+}

src/Microsoft.Extensions.WebEncoders/WebEncoderOptions.cs

@@ -0,0 +1,21 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Text.Encodings.Web;
+
+namespace Microsoft.Extensions.WebEncoders
+{
+    /// <summary>
+    /// Specifies options common to all three encoders (HtmlEncode, JavaScriptEncode, UrlEncode).
+    /// </summary>
+    public sealed class WebEncoderOptions
+    {
+        /// <summary>
+        /// Specifies which code points are allowed to be represented unescaped by the encoders.
+        /// </summary>
+        /// <remarks>
+        /// If this property is null, then the encoders will use their default allow lists.
+        /// </remarks>
+        public TextEncoderSettings TextEncoderSettings { get; set; }
+    }
+}

src/Microsoft.Extensions.WebEncoders/project.json

@@ -0,0 +1,27 @@
+{
+  "version": "1.0.0-*",
+  "description": "Contains registration and configuration APIs for the core framework encoders.",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/aspnet/httpabstractions"
+  },
+  "compilationOptions": {
+    "warningsAsErrors": true,
+    "allowUnsafe": true,
+    "keyFile": "../../tools/Key.snk"
+  },
+  "dependencies": {
+    "Microsoft.Extensions.DependencyInjection.Abstractions": "1.0.0-*",
+    "Microsoft.Extensions.Options": "1.0.0-*",
+    "System.Text.Encodings.Web": "4.0.0-*"
+  },
+  "frameworks": {
+    "net451": {
+      "frameworkAssemblies": {
+        "System.IO": "",
+        "System.Runtime": ""
+      }
+    },
+    "dotnet5.4": {}
+  }
+}

test/Microsoft.Extensions.WebEncoders.Tests/EncoderServiceCollectionExtensionsTests.cs

@@ -0,0 +1,90 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Text.Encodings.Web;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.WebEncoders.Testing;
+using Xunit;
+
+namespace Microsoft.Extensions.WebEncoders
+{
+    public class EncoderServiceCollectionExtensionsTests
+    {
+        [Fact]
+        public void AddWebEncoders_WithoutOptions_RegistersDefaultEncoders()
+        {
+            // Arrange
+            var serviceCollection = new ServiceCollection();
+
+            // Act
+            serviceCollection.AddWebEncoders();
+
+            // Assert
+            var serviceProvider = serviceCollection.BuildServiceProvider();
+            Assert.Same(HtmlEncoder.Default, serviceProvider.GetRequiredService<HtmlEncoder>()); // default encoder
+            Assert.Same(HtmlEncoder.Default, serviceProvider.GetRequiredService<HtmlEncoder>()); // as singleton instance
+            Assert.Same(JavaScriptEncoder.Default, serviceProvider.GetRequiredService<JavaScriptEncoder>()); // default encoder
+            Assert.Same(JavaScriptEncoder.Default, serviceProvider.GetRequiredService<JavaScriptEncoder>()); // as singleton instance
+            Assert.Same(UrlEncoder.Default, serviceProvider.GetRequiredService<UrlEncoder>()); // default encoder
+            Assert.Same(UrlEncoder.Default, serviceProvider.GetRequiredService<UrlEncoder>()); // as singleton instance
+        }
+
+        [Fact]
+        public void AddWebEncoders_WithOptions_RegistersEncodersWithCustomCodeFilter()
+        {
+            // Arrange
+            var serviceCollection = new ServiceCollection();
+
+            // Act
+            serviceCollection.AddWebEncoders(options =>
+            {
+                options.TextEncoderSettings = new TextEncoderSettings();
+                options.TextEncoderSettings.AllowCharacters("ace".ToCharArray()); // only these three chars are allowed
+            });
+
+            // Assert
+            var serviceProvider = serviceCollection.BuildServiceProvider();
+
+            var htmlEncoder = serviceProvider.GetRequiredService<HtmlEncoder>();
+            Assert.Equal("a&#x62;c&#x64;e", htmlEncoder.Encode("abcde"));
+            Assert.Same(htmlEncoder, serviceProvider.GetRequiredService<HtmlEncoder>()); // as singleton instance
+
+            var javaScriptEncoder = serviceProvider.GetRequiredService<JavaScriptEncoder>();
+            Assert.Equal(@"a\u0062c\u0064e", javaScriptEncoder.Encode("abcde"));
+            Assert.Same(javaScriptEncoder, serviceProvider.GetRequiredService<JavaScriptEncoder>()); // as singleton instance
+
+            var urlEncoder = serviceProvider.GetRequiredService<UrlEncoder>();
+            Assert.Equal("a%62c%64e", urlEncoder.Encode("abcde"));
+            Assert.Same(urlEncoder, serviceProvider.GetRequiredService<UrlEncoder>()); // as singleton instance
+        }
+
+        [Fact]
+        public void AddWebEncoders_DoesNotOverrideExistingRegisteredEncoders()
+        {
+            // Arrange
+            var serviceCollection = new ServiceCollection();
+
+            // Act
+            serviceCollection.AddSingleton<HtmlEncoder, HtmlTestEncoder>();
+            serviceCollection.AddSingleton<JavaScriptEncoder, JavaScriptTestEncoder>();
+            // we don't register an existing URL encoder
+            serviceCollection.AddWebEncoders(options =>
+            {
+                options.TextEncoderSettings = new TextEncoderSettings();
+                options.TextEncoderSettings.AllowCharacters("ace".ToCharArray()); // only these three chars are allowed
+            });
+
+            // Assert
+            var serviceProvider = serviceCollection.BuildServiceProvider();
+
+            var htmlEncoder = serviceProvider.GetHtmlEncoder();
+            Assert.Equal("HtmlEncode[[abcde]]", htmlEncoder.Encode("abcde"));
+
+            var javaScriptEncoder = serviceProvider.GetJavaScriptEncoder();
+            Assert.Equal("JavaScriptEncode[[abcde]]", javaScriptEncoder.Encode("abcde"));
+
+            var urlEncoder = serviceProvider.GetUrlEncoder();
+            Assert.Equal("a%62c%64e", urlEncoder.Encode("abcde"));
+        }
+    }
+}

test/Microsoft.Extensions.WebEncoders.Tests/EncoderServiceProviderExtensionsTests.cs

@@ -0,0 +1,103 @@
+// Copyright (c) .NET Foundation. 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.Text.Encodings.Web;
+using Xunit;
+
+namespace Microsoft.Extensions.WebEncoders
+{
+    public class EncoderServiceProviderExtensionsTests
+    {
+        [Fact]
+        public void GetHtmlEncoder_ServiceProviderDoesNotHaveEncoder_UsesDefault()
+        {
+            // Arrange
+            var serviceProvider = new TestServiceProvider();
+
+            // Act
+            var retVal = serviceProvider.GetHtmlEncoder();
+
+            // Assert
+            Assert.Same(HtmlEncoder.Default, retVal);
+        }
+
+        [Fact]
+        public void GetHtmlEncoder_ServiceProviderHasEncoder_ReturnsRegisteredInstance()
+        {
+            // Arrange
+            var expectedEncoder = HtmlEncoder.Default;
+            var serviceProvider = new TestServiceProvider() { Service = expectedEncoder };
+
+            // Act
+            var retVal = serviceProvider.GetHtmlEncoder();
+
+            // Assert
+            Assert.Same(expectedEncoder, retVal);
+        }
+
+        [Fact]
+        public void GetJavaScriptEncoder_ServiceProviderDoesNotHaveEncoder_UsesDefault()
+        {
+            // Arrange
+            var serviceProvider = new TestServiceProvider();
+
+            // Act
+            var retVal = serviceProvider.GetJavaScriptEncoder();
+
+            // Assert
+            Assert.Same(JavaScriptEncoder.Default, retVal);
+        }
+
+        [Fact]
+        public void GetJavaScriptEncoder_ServiceProviderHasEncoder_ReturnsRegisteredInstance()
+        {
+            // Arrange
+            var expectedEncoder = JavaScriptEncoder.Default;
+            var serviceProvider = new TestServiceProvider() { Service = expectedEncoder };
+
+            // Act
+            var retVal = serviceProvider.GetJavaScriptEncoder();
+
+            // Assert
+            Assert.Same(expectedEncoder, retVal);
+        }
+
+        [Fact]
+        public void GetUrlEncoder_ServiceProviderDoesNotHaveEncoder_UsesDefault()
+        {
+            // Arrange
+            var serviceProvider = new TestServiceProvider();
+
+            // Act
+            var retVal = serviceProvider.GetUrlEncoder();
+
+            // Assert
+            Assert.Same(UrlEncoder.Default, retVal);
+        }
+
+        [Fact]
+        public void GetUrlEncoder_ServiceProviderHasEncoder_ReturnsRegisteredInstance()
+        {
+            // Arrange
+            var expectedEncoder = UrlEncoder.Default;
+            var serviceProvider = new TestServiceProvider() { Service = expectedEncoder };
+
+            // Act
+            var retVal = serviceProvider.GetUrlEncoder();
+
+            // Assert
+            Assert.Same(expectedEncoder, retVal);
+        }
+
+        private class TestServiceProvider : IServiceProvider
+        {
+            public object Service { get; set; }
+
+            public object GetService(Type serviceType)
+            {
+                return Service;
+            }
+        }
+    }
+}

test/Microsoft.Extensions.WebEncoders.Tests/HtmlTestEncoderTest.cs

@@ -0,0 +1,26 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Xunit;
+
+namespace Microsoft.Extensions.WebEncoders.Testing
+{
+    public class HtmlTestEncoderTest
+    {
+        [Theory]
+        [InlineData("", "")]
+        [InlineData("abcd", "HtmlEncode[[abcd]]")]
+        [InlineData("<<''\"\">>", "HtmlEncode[[<<''\"\">>]]")]
+        public void StringEncode_EncodesAsExpected(string input, string expectedOutput)
+        {
+            // Arrange
+            var encoder = new HtmlTestEncoder();
+
+            // Act
+            var output = encoder.Encode(input);
+
+            // Assert
+            Assert.Equal(expectedOutput, output);
+        }
+    }
+}

test/Microsoft.Extensions.WebEncoders.Tests/Microsoft.Extensions.WebEncoders.Tests.xproj

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <VisualStudioVersion Condition="'$(VisualStudioVersion)' == ''">14.0</VisualStudioVersion>
+    <VSToolsPath Condition="'$(VSToolsPath)' == ''">$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)</VSToolsPath>
+  </PropertyGroup>
+  <Import Project="$(VSToolsPath)\DNX\Microsoft.DNX.Props" Condition="'$(VSToolsPath)' != ''" />
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>7ae2731d-43cd-4cf8-850a-4914de2ce930</ProjectGuid>
+    <BaseIntermediateOutputPath Condition="'$(BaseIntermediateOutputPath)'=='' ">..\..\artifacts\obj\$(MSBuildProjectName)</BaseIntermediateOutputPath>
+    <OutputPath Condition="'$(OutputPath)'=='' ">..\..\artifacts\bin\$(MSBuildProjectName)\</OutputPath>
+  </PropertyGroup>
+  <PropertyGroup>
+    <SchemaVersion>2.0</SchemaVersion>
+  </PropertyGroup>
+  <ItemGroup>
+    <Service Include="{82a7f48d-3b50-4b1e-b82e-3ada8210c358}" />
+  </ItemGroup>
+  <Import Project="$(VSToolsPath)\DNX\Microsoft.DNX.targets" Condition="'$(VSToolsPath)' != ''" />
+</Project>

test/Microsoft.Extensions.WebEncoders.Tests/project.json

@@ -0,0 +1,24 @@
+{
+  "dependencies": {
+    "Microsoft.Extensions.DependencyInjection": "1.0.0-*",
+    "Microsoft.Extensions.WebEncoders": "1.0.0-*",
+    "Newtonsoft.Json": "6.0.6",
+    "xunit.runner.aspnet": "2.0.0-aspnet-*"
+  },
+  "commands": {
+    "test": "xunit.runner.aspnet"
+  },
+  "compilationOptions": {
+    "allowUnsafe": true,
+    "warningsAsErrors": true,
+    "keyFile": "../../tools/Key.snk"
+  },
+  "frameworks": {
+    "dnx451": { },
+    "dnxcore50": {
+      "dependencies": {
+        "System.Text.Encoding.Extensions": "4.0.11-*"
+      }
+    }
+  }
+}