Initial checkin of gRPC to third_party/

third_party/grpc/src/csharp/Grpc.Core/ClientBase.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.Text.RegularExpressions;
+using System.Threading.Tasks;
+
+namespace Grpc.Core
+{
+    /// <summary>
+    /// Interceptor for call headers.
+    /// </summary>
+    /// <remarks>Header interceptor is no longer to recommented 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>
+    /// Base class for client-side stubs.
+    /// </summary>
+    public abstract class ClientBase
+    {
+        readonly Channel channel;
+
+        /// <summary>
+        /// Initializes a new instance of <c>ClientBase</c> class.
+        /// </summary>
+        /// <param name="channel">The channel to use for remote call invocation.</param>
+        public ClientBase(Channel channel)
+        {
+            this.channel = channel;
+        }
+
+        /// <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>
+        /// Channel associated with this client.
+        /// </summary>
+        public Channel Channel
+        {
+            get
+            {
+                return this.channel;
+            }
+        }
+
+        /// <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);
+        }
+    }
+}