add ClientBase.WithHost and get rid of HeaderInterceptor

src/csharp/Grpc.Core/ClientBase.cs

@@ -38,14 +38,6 @@ using Grpc.Core.Utils;
 
 namespace Grpc.Core
 {
-    /// <summary>
-    /// Interceptor for call headers.
-    /// </summary>
-    /// <remarks>Header interceptor is no longer the recommended way to perform authentication.
-    /// For header (initial metadata) based auth such as OAuth2 or JWT access token, use <see cref="MetadataCredentials"/>.
-    /// </remarks>
-    public delegate void HeaderInterceptor(IMethod method, Metadata metadata);
-
     /// <summary>
     /// Generic base class for client-side stubs.
     /// </summary>
@@ -68,6 +60,19 @@ namespace Grpc.Core
         {
         }
 
+        /// <summary>
+        /// Creates a new client that sets host field for calls explicitly.
+        /// gRPC supports multiple "hosts" being served by a single server.
+        /// By default (if a client was not created by calling this method),
+        /// host <c>null</c> with the meaning "use default host" is used.
+        /// </summary>
+        public T WithHost(string host)
+        {
+            GrpcPreconditions.CheckNotNull(host, "host");
+            var decoratedInvoker = new InterceptingCallInvoker(CallInvoker, hostInterceptor: (h) => host);
+            return NewInstance(decoratedInvoker);
+        }
+
         /// <summary>
         /// Creates a new instance of client from given <c>CallInvoker</c>.
         /// </summary>
@@ -105,53 +110,5 @@ namespace Grpc.Core
         {
             get { return this.callInvoker; }
         }
-
-        /// <summary>
-        /// Can be used to register a custom header interceptor.
-        /// The interceptor is invoked each time a new call on this client is started.
-        /// It is not recommented to use header interceptor to add auth headers to RPC calls.
-        /// </summary>
-        /// <seealso cref="HeaderInterceptor"/>
-        public HeaderInterceptor HeaderInterceptor
-        {
-            get;
-            set;
-        }
-
-        /// <summary>
-        /// gRPC supports multiple "hosts" being served by a single server. 
-        /// This property can be used to set the target host explicitly.
-        /// By default, this will be set to <c>null</c> with the meaning
-        /// "use default host".
-        /// </summary>
-        //public string Host
-        //{
-        //    get;
-        //    set;
-        //}
-
-        /// <summary>
-        /// Creates a new call to given method.
-        /// </summary>
-        /// <param name="method">The method to invoke.</param>
-        /// <param name="options">The call options.</param>
-        /// <typeparam name="TRequest">Request message type.</typeparam>
-        /// <typeparam name="TResponse">Response message type.</typeparam>
-        /// <returns>The call invocation details.</returns>
-        //protected CallInvocationDetails<TRequest, TResponse> CreateCall<TRequest, TResponse>(Method<TRequest, TResponse> method, CallOptions options)
-        //    where TRequest : class
-        //    where TResponse : class
-        //{
-        //    var interceptor = HeaderInterceptor;
-        //    if (interceptor != null)
-        //    {
-        //        if (options.Headers == null)
-        //        {
-        //            options = options.WithHeaders(new Metadata());
-        //        }
-        //        interceptor(method, options.Headers);
-        //    }
-        //    return new CallInvocationDetails<TRequest, TResponse>(channel, method, Host, options);
-        //}
     }
 }

src/csharp/Grpc.Core/DefaultCallInvoker.cs

@@ -75,7 +75,7 @@ namespace Grpc.Core
         /// Invokes a server streaming call asynchronously.
         /// In server streaming scenario, client sends on request and server responds with a stream of responses.
         /// </summary>
-        public override  AsyncServerStreamingCall<TResponse> AsyncServerStreamingCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options, TRequest request)
+        public override AsyncServerStreamingCall<TResponse> AsyncServerStreamingCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options, TRequest request)
         {
             var call = CreateCall(method, host, options);
             return Calls.AsyncServerStreamingCall(call, request);

src/csharp/Grpc.Core/Grpc.Core.csproj

@@ -131,6 +131,7 @@
     <Compile Include="Utils\GrpcPreconditions.cs" />
     <Compile Include="CallInvoker.cs" />
     <Compile Include="DefaultCallInvoker.cs" />
+    <Compile Include="InterceptingCallInvoker.cs" />
   </ItemGroup>
   <ItemGroup>
     <None Include="Grpc.Core.nuspec" />

src/csharp/Grpc.Core/InterceptingCallInvoker.cs

+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Threading.Tasks;
+using Grpc.Core.Internal;
+using Grpc.Core.Utils;
+
+namespace Grpc.Core
+{
+    /// <summary>
+    /// Decorates an underlying <c>CallInvoker</c> to intercept call invocations.
+    /// </summary>
+    internal class InterceptingCallInvoker : CallInvoker
+    {
+        readonly CallInvoker callInvoker;
+        readonly Func<string, string> hostInterceptor;
+        readonly Func<CallOptions, CallOptions> callOptionsInterceptor;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Grpc.Core.InterceptingCallInvoker"/> class.
+        /// </summary>
+        /// <param name="callInvoker">CallInvoker to decorate.</param>
+        public InterceptingCallInvoker(CallInvoker callInvoker,
+            Func<string, string> hostInterceptor = null,
+            Func<CallOptions, CallOptions> callOptionsInterceptor = null)
+        {
+            this.callInvoker = GrpcPreconditions.CheckNotNull(callInvoker);
+            this.hostInterceptor = hostInterceptor;
+            this.callOptionsInterceptor = callOptionsInterceptor;
+        }
+
+        /// <summary>
+        /// Intercepts a unary call.
+        /// </summary>
+        public override TResponse BlockingUnaryCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options, TRequest request)
+        {
+            host = InterceptHost(host);
+            options = InterceptCallOptions(options);
+            return callInvoker.BlockingUnaryCall(method, host, options, request);
+        }
+
+        /// <summary>
+        /// Invokes a simple remote call asynchronously.
+        /// </summary>
+        public override AsyncUnaryCall<TResponse> AsyncUnaryCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options, TRequest request)
+        {
+            host = InterceptHost(host);
+            options = InterceptCallOptions(options);
+            return callInvoker.AsyncUnaryCall(method, host, options, request);
+        }
+
+        /// <summary>
+        /// Invokes a server streaming call asynchronously.
+        /// In server streaming scenario, client sends on request and server responds with a stream of responses.
+        /// </summary>
+        public override AsyncServerStreamingCall<TResponse> AsyncServerStreamingCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options, TRequest request)
+        {
+            host = InterceptHost(host);
+            options = InterceptCallOptions(options);
+            return callInvoker.AsyncServerStreamingCall(method, host, options, request);
+        }
+
+        /// <summary>
+        /// Invokes a client streaming call asynchronously.
+        /// In client streaming scenario, client sends a stream of requests and server responds with a single response.
+        /// </summary>
+        public override AsyncClientStreamingCall<TRequest, TResponse> AsyncClientStreamingCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options)
+        {
+            host = InterceptHost(host);
+            options = InterceptCallOptions(options);
+            return callInvoker.AsyncClientStreamingCall(method, host, options);
+        }
+
+        /// <summary>
+        /// Invokes a duplex streaming call asynchronously.
+        /// In duplex streaming scenario, client sends a stream of requests and server responds with a stream of responses.
+        /// The response stream is completely independent and both side can be sending messages at the same time.
+        /// </summary>
+        public override AsyncDuplexStreamingCall<TRequest, TResponse> AsyncDuplexStreamingCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options)
+        {
+            host = InterceptHost(host);
+            options = InterceptCallOptions(options);
+            return callInvoker.AsyncDuplexStreamingCall(method, host, options);
+        }
+
+        private string InterceptHost(string host)
+        {
+            // only set host if not already set to support composing interceptors.
+            if (hostInterceptor == null || host != null)
+            {
+                return host;
+            }
+            return hostInterceptor(host);
+        }
+
+        private CallOptions InterceptCallOptions(CallOptions options)
+        {
+            if (callOptionsInterceptor == null)
+            {
+                return options;
+            }
+            return callOptionsInterceptor(options);
+        }
+    }
+}

src/csharp/Grpc.IntegrationTesting/Grpc.IntegrationTesting.csproj

@@ -84,7 +84,6 @@
     <Compile Include="..\Grpc.Core\Version.cs">
       <Link>Version.cs</Link>
     </Compile>
-    <Compile Include="HeaderInterceptorTest.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Empty.cs" />
     <Compile Include="Messages.cs" />

src/csharp/tests.json

@@ -35,7 +35,6 @@
     "Math.Tests.MathClientServerTest",
     "Grpc.HealthCheck.Tests.HealthClientServerTest",
     "Grpc.HealthCheck.Tests.HealthServiceImplTest",
-    "Grpc.IntegrationTesting.HeaderInterceptorTest",
     "Grpc.IntegrationTesting.HistogramTest",
     "Grpc.IntegrationTesting.InteropClientServerTest",
     "Grpc.IntegrationTesting.MetadataCredentialsTest",