Added more tests and error handling for construction of middleware classes #236

src/Microsoft.AspNet.Http.Abstractions/Extensions/UseMiddlewareExtensions.cs

@@ -6,12 +6,14 @@ using System.Linq;
 using System.Reflection;
 using System.Threading.Tasks;
 using Microsoft.AspNet.Http;
+using Microsoft.AspNet.Http.Abstractions;
 using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Builder
 {
     public static class UseMiddlewareExtensions
     {
+        const string InvokeMethodName = "Invoke";
         public static IApplicationBuilder UseMiddleware<T>(this IApplicationBuilder builder, params object[] args)
         {
             return builder.UseMiddleware(typeof(T), args);
@@ -22,24 +24,44 @@ namespace Microsoft.AspNet.Builder
             var applicationServices = builder.ApplicationServices;
             return builder.Use(next =>
             {
-                var instance = ActivatorUtilities.CreateInstance(builder.ApplicationServices, middleware, new[] { next }.Concat(args).ToArray());
+                var methods = middleware.GetMethods(BindingFlags.Instance | BindingFlags.Public);
-                var methodinfo = middleware.GetMethod("Invoke", BindingFlags.Instance | BindingFlags.Public);
+                var invokeMethods = methods.Where(m => string.Equals(m.Name, InvokeMethodName, StringComparison.Ordinal)).ToArray();
-                var parameters = methodinfo.GetParameters();
+                if (invokeMethods.Length > 1)
-                if (parameters[0].ParameterType != typeof(HttpContext))
                 {
-                    throw new Exception("Middleware Invoke method must take first argument of HttpContext");
+                    throw new InvalidOperationException(Resources.FormatException_UseMiddleMutlipleInvokes(InvokeMethodName));
                 }
+
+                if (invokeMethods.Length  == 0)
+                {
+                    throw new InvalidOperationException(Resources.FormatException_UseMiddlewareNoInvokeMethod(InvokeMethodName));
+                }
+
+                var methodinfo = invokeMethods[0];
+                if (!typeof(Task).IsAssignableFrom(methodinfo.ReturnType))
+                {
+                    throw new InvalidOperationException(Resources.FormatException_UseMiddlewareNonTaskReturnType(InvokeMethodName, nameof(Task)));
+                }
+
+                var parameters = methodinfo.GetParameters();
+                if (parameters.Length == 0 || parameters[0].ParameterType != typeof(HttpContext))
+                {
+                    throw new InvalidOperationException(Resources.FormatException_UseMiddlewareNoParameters(InvokeMethodName,nameof(HttpContext)));
+                }
+
+                var instance = ActivatorUtilities.CreateInstance(builder.ApplicationServices, middleware, new[] { next }.Concat(args).ToArray());
                 if (parameters.Length == 1)
                 {
                     return (RequestDelegate)methodinfo.CreateDelegate(typeof(RequestDelegate), instance);
                 }
+
                 return context =>
                 {
                     var serviceProvider = context.RequestServices ?? context.ApplicationServices ?? applicationServices;
                     if (serviceProvider == null)
                     {
-                        throw new Exception("IServiceProvider is not available");
+                        throw new InvalidOperationException(Resources.FormatException_UseMiddlewareIServiceProviderNotAvailable(nameof(IServiceProvider)));
                     }
+
                     var arguments = new object[parameters.Length];
                     arguments[0] = context;
                     for(var index = 1; index != parameters.Length; ++index)

src/Microsoft.AspNet.Http.Abstractions/Properties/AssemblyInfo.cs

@@ -2,5 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System.Reflection;
+using System.Runtime.CompilerServices;
 
-[assembly: AssemblyMetadata("Serviceable", "True")]
+[assembly: AssemblyMetadata("Serviceable", "True")]
+[assembly: InternalsVisibleTo("Microsoft.AspNet.Http.Abstractions.Tests")]

src/Microsoft.AspNet.Http.Abstractions/Properties/Resources.Designer.cs

@@ -0,0 +1,110 @@
+// <auto-generated />
+namespace Microsoft.AspNet.Http.Abstractions
+{
+    using System.Globalization;
+    using System.Reflection;
+    using System.Resources;
+
+    internal static class Resources
+    {
+        private static readonly ResourceManager _resourceManager
+            = new ResourceManager("Microsoft.AspNet.Http.Abstractions.Resources", typeof(Resources).GetTypeInfo().Assembly);
+
+        /// <summary>
+        /// '{0}' is not available.
+        /// </summary>
+        internal static string Exception_UseMiddlewareIServiceProviderNotAvailable
+        {
+            get { return GetString("Exception_UseMiddlewareIServiceProviderNotAvailable"); }
+        }
+
+        /// <summary>
+        /// '{0}' is not available.
+        /// </summary>
+        internal static string FormatException_UseMiddlewareIServiceProviderNotAvailable(object p0)
+        {
+            return string.Format(CultureInfo.CurrentCulture, GetString("Exception_UseMiddlewareIServiceProviderNotAvailable"), p0);
+        }
+
+        /// <summary>
+        /// No public '{0}' method found.
+        /// </summary>
+        internal static string Exception_UseMiddlewareNoInvokeMethod
+        {
+            get { return GetString("Exception_UseMiddlewareNoInvokeMethod"); }
+        }
+
+        /// <summary>
+        /// No public '{0}' method found.
+        /// </summary>
+        internal static string FormatException_UseMiddlewareNoInvokeMethod(object p0)
+        {
+            return string.Format(CultureInfo.CurrentCulture, GetString("Exception_UseMiddlewareNoInvokeMethod"), p0);
+        }
+
+        /// <summary>
+        /// '{0}' does not return an object of type '{1}'.
+        /// </summary>
+        internal static string Exception_UseMiddlewareNonTaskReturnType
+        {
+            get { return GetString("Exception_UseMiddlewareNonTaskReturnType"); }
+        }
+
+        /// <summary>
+        /// '{0}' does not return an object of type '{1}'.
+        /// </summary>
+        internal static string FormatException_UseMiddlewareNonTaskReturnType(object p0, object p1)
+        {
+            return string.Format(CultureInfo.CurrentCulture, GetString("Exception_UseMiddlewareNonTaskReturnType"), p0, p1);
+        }
+
+        /// <summary>
+        /// The '{0}' method's first argument must be of type '{1}'.
+        /// </summary>
+        internal static string Exception_UseMiddlewareNoParameters
+        {
+            get { return GetString("Exception_UseMiddlewareNoParameters"); }
+        }
+
+        /// <summary>
+        /// The '{0}' method's first argument must be of type '{1}'.
+        /// </summary>
+        internal static string FormatException_UseMiddlewareNoParameters(object p0, object p1)
+        {
+            return string.Format(CultureInfo.CurrentCulture, GetString("Exception_UseMiddlewareNoParameters"), p0, p1);
+        }
+
+        /// <summary>
+        /// Multiple public '{0}' methods are available.
+        /// </summary>
+        internal static string Exception_UseMiddleMutlipleInvokes
+        {
+            get { return GetString("Exception_UseMiddleMutlipleInvokes"); }
+        }
+
+        /// <summary>
+        /// Multiple public '{0}' methods are available.
+        /// </summary>
+        internal static string FormatException_UseMiddleMutlipleInvokes(object p0)
+        {
+            return string.Format(CultureInfo.CurrentCulture, GetString("Exception_UseMiddleMutlipleInvokes"), p0);
+        }
+
+        private static string GetString(string name, params string[] formatterNames)
+        {
+            var value = _resourceManager.GetString(name);
+
+            System.Diagnostics.Debug.Assert(value != null);
+
+            if (formatterNames != null)
+            {
+                for (var i = 0; i < formatterNames.Length; i++)
+                {
+                    value = value.Replace("{" + formatterNames[i] + "}", "{" + i + "}");
+                }
+            }
+
+            return value;
+        }
+    }
+}

src/Microsoft.AspNet.Http.Abstractions/Resources.resx

@@ -0,0 +1,135 @@
+<?xml version="1.0" encoding="utf-8"?>
+<root>
+  <!-- 
+    Microsoft ResX Schema 
+    
+    Version 2.0
+    
+    The primary goals of this format is to allow a simple XML format 
+    that is mostly human readable. The generation and parsing of the 
+    various data types are done through the TypeConverter classes 
+    associated with the data types.
+    
+    Example:
+    
+    ... ado.net/XML headers & schema ...
+    <resheader name="resmimetype">text/microsoft-resx</resheader>
+    <resheader name="version">2.0</resheader>
+    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
+    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
+    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
+    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
+    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
+        <value>[base64 mime encoded serialized .NET Framework object]</value>
+    </data>
+    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
+        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
+        <comment>This is a comment</comment>
+    </data>
+                
+    There are any number of "resheader" rows that contain simple 
+    name/value pairs.
+    
+    Each data row contains a name, and value. The row also contains a 
+    type or mimetype. Type corresponds to a .NET class that support 
+    text/value conversion through the TypeConverter architecture. 
+    Classes that don't support this are serialized and stored with the 
+    mimetype set.
+    
+    The mimetype is used for serialized objects, and tells the 
+    ResXResourceReader how to depersist the object. This is currently not 
+    extensible. For a given mimetype the value must be set accordingly:
+    
+    Note - application/x-microsoft.net.object.binary.base64 is the format 
+    that the ResXResourceWriter will generate, however the reader can 
+    read any of the formats listed below.
+    
+    mimetype: application/x-microsoft.net.object.binary.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
+            : and then encoded with base64 encoding.
+    
+    mimetype: application/x-microsoft.net.object.soap.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
+            : and then encoded with base64 encoding.
+
+    mimetype: application/x-microsoft.net.object.bytearray.base64
+    value   : The object must be serialized into a byte array 
+            : using a System.ComponentModel.TypeConverter
+            : and then encoded with base64 encoding.
+    -->
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <data name="Exception_UseMiddlewareIServiceProviderNotAvailable" xml:space="preserve">
+    <value>'{0}' is not available.</value>
+  </data>
+  <data name="Exception_UseMiddlewareNoInvokeMethod" xml:space="preserve">
+    <value>No public '{0}' method found.</value>
+  </data>
+  <data name="Exception_UseMiddlewareNonTaskReturnType" xml:space="preserve">
+    <value>'{0}' does not return an object of type '{1}'.</value>
+  </data>
+  <data name="Exception_UseMiddlewareNoParameters" xml:space="preserve">
+    <value>The '{0}' method's first argument must be of type '{1}'.</value>
+  </data>
+  <data name="Exception_UseMiddleMutlipleInvokes" xml:space="preserve">
+    <value>Multiple public '{0}' methods are available.</value>
+  </data>
+</root>

test/Microsoft.AspNet.Http.Abstractions.Tests/UseMiddlewareTest.cs

@@ -0,0 +1,112 @@
+// 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.Threading.Tasks;
+using Microsoft.AspNet.Builder;
+using Microsoft.AspNet.Builder.Internal;
+using Microsoft.AspNet.Http.Abstractions;
+using Xunit;
+
+namespace Microsoft.AspNet.Http
+{
+    public class UseMiddlewareTest
+    {
+        [Fact]
+        public void UseMiddleware_WithNoParameters_ThrowsException()
+        {
+            var mockServiceProvider = new DummyServiceProvider();
+            var builder = new ApplicationBuilder(mockServiceProvider);
+            builder.UseMiddleware(typeof(MiddlewareNoParametersStub));
+            var exception = Assert.Throws<InvalidOperationException>(() => builder.Build());
+
+            Assert.Equal(Resources.FormatException_UseMiddlewareNoParameters("Invoke",nameof(HttpContext)), exception.Message); 
+        }
+
+        [Fact]
+        public void UseMiddleware_NonTaskReturnType_ThrowsException()
+        {
+            var mockServiceProvider = new DummyServiceProvider();
+            var builder = new ApplicationBuilder(mockServiceProvider);
+            builder.UseMiddleware(typeof(MiddlewareNonTaskReturnStub));
+            var exception = Assert.Throws<InvalidOperationException>(() => builder.Build());
+            Assert.Equal(Resources.FormatException_UseMiddlewareNonTaskReturnType("Invoke", nameof(Task)), exception.Message);
+        }
+
+        [Fact]
+        public void UseMiddleware_NoInvokeMethod_ThrowsException()
+        {          
+            var mockServiceProvider = new DummyServiceProvider();
+            var builder = new ApplicationBuilder(mockServiceProvider);
+            builder.UseMiddleware(typeof(MiddlewareNoInvokeStub));
+            var exception = Assert.Throws<InvalidOperationException>(() => builder.Build());
+            Assert.Equal(Resources.FormatException_UseMiddlewareNoInvokeMethod("Invoke"), exception.Message);
+        }
+
+        [Fact]
+        public void UseMiddleware_MutlipleInvokeMethods_ThrowsException()
+        {
+            var mockServiceProvider = new DummyServiceProvider();
+            var builder = new ApplicationBuilder(mockServiceProvider);
+            builder.UseMiddleware(typeof(MiddlewareMultipleInvokesStub));
+            var exception = Assert.Throws<InvalidOperationException>(() => builder.Build());
+            Assert.Equal(Resources.FormatException_UseMiddleMutlipleInvokes("Invoke"), exception.Message);
+        }
+
+        private class DummyServiceProvider : IServiceProvider
+        {
+            public object GetService(Type serviceType)
+            {
+                return null;
+            }
+        }
+
+        private class MiddlewareNoParametersStub
+        {
+            public MiddlewareNoParametersStub(RequestDelegate next)
+            {
+            }
+
+            public Task Invoke()
+            {
+                return Task.FromResult(0);
+            }
+        }
+
+        private class MiddlewareNonTaskReturnStub
+        {
+            public MiddlewareNonTaskReturnStub(RequestDelegate next)
+            {
+            }
+
+            public int Invoke()
+            {
+                return 0;
+            }
+        }
+         
+        private class MiddlewareNoInvokeStub
+        {
+            public MiddlewareNoInvokeStub(RequestDelegate next)
+            {
+            }
+        }
+
+        private class MiddlewareMultipleInvokesStub
+        {
+            public MiddlewareMultipleInvokesStub(RequestDelegate next)
+            {
+            }
+
+            public Task Invoke(HttpContext context)
+            {
+                return Task.FromResult(0);
+            }
+
+            public Task Invoke(HttpContext context, int i)
+            {
+                return Task.FromResult(0);
+            }
+        }
+    }
+}