Add C# Interceptor base class

1 files changed, 281 insertions, 0 deletions

diff --git a/src/csharp/Grpc.Core/Interceptors/Interceptor.cs b/src/csharp/Grpc.Core/Interceptors/Interceptor.cs
new file mode 100644
index 0000000000..0f32e8b420
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+++ b/src/csharp/Grpc.Core/Interceptors/Interceptor.cs
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+#region Copyright notice and license
+
+// Copyright 2018 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#endregion
+
+using System;
+using System.Reflection;
+using System.Threading.Tasks;
+using Grpc.Core.Internal;
+
+namespace Grpc.Core.Interceptors
+{
+    /// <summary>
+    /// Carries along the context associated with intercepted invocations on the client side.
+    /// This is an EXPERIMENTAL API.
+    /// </summary>
+    public class ClientInterceptorContext<TRequest, TResponse>
+        where TRequest : class
+        where TResponse : class
+    {
+        /// <summary>
+        /// Creates a new instance of <see cref="Grpc.Core.Interceptors.ClientInterceptorContext{TRequest, TResponse}" />
+        /// with the specified method, host, and call options.
+        /// </summary>
+        /// <param name="method">A <see cref="Grpc.Core.Method{TRequest, TResponse}"/> object representing the method to be invoked.</param>
+        /// <param name="host">The host to dispatch the current call to.</param>
+        /// <param name="options">A <see cref="Grpc.Core.CallOptions"/> instance containing the call options of the current call.</param>
+
+        public ClientInterceptorContext(Method<TRequest, TResponse> method, string host, CallOptions options)
+        {
+            Method = method;
+            Host = host;
+            Options = options;
+        }
+
+        /// <summary>
+        /// Gets the <see cref="Grpc.Core.Method{TRequest, TResponse}"/> representing
+        /// the method to be invoked.
+        /// </summary>
+        public Method<TRequest, TResponse> Method { get; }
+
+        /// <summary>
+        /// Gets the host that the currect invocation will be dispatched to.
+        /// </summary>
+        public string Host { get; }
+
+        /// <summary>
+        /// Gets the <see cref="Grpc.Core.CallOptions"/> structure representing the
+        /// call options associated with the current invocation.
+        /// </summary>
+        public CallOptions Options { get; }
+    }
+
+    /// <summary>
+    /// Serves as the base class for gRPC interceptors.
+    /// This is an EXPERIMENTAL API.
+    /// </summary>
+    public abstract class Interceptor
+    {
+        /// <summary>
+        /// Represents a continuation for intercepting simple blocking invocations.
+        /// </summary>
+        /// <typeparam name="TRequest">Request message type for this invocation.</typeparam>
+        /// <typeparam name="TResponse">Response message type for this invocation.</typeparam>
+        /// <param name="request">The request value to continue the invocation with.</param>
+        /// <param name="context">
+        /// The <see cref="Grpc.Core.Interceptors.ClientInterceptorContext{TRequest, TResponse}"/>
+        /// instance to pass to the next step in the invocation process.
+        /// </param>
+        public delegate TResponse BlockingUnaryCallContinuation<TRequest, TResponse>(TRequest request, ClientInterceptorContext<TRequest, TResponse> context)
+            where TRequest : class
+            where TResponse : class;
+
+        /// <summary>
+        /// Represents a continuation for intercepting simple asynchronous invocations.
+        /// </summary>
+        /// <typeparam name="TRequest">Request message type for this invocation.</typeparam>
+        /// <typeparam name="TResponse">Response message type for this invocation.</typeparam>
+        /// <param name="request">The request value to continue the invocation with.</param>
+        /// <param name="context">
+        /// The <see cref="Grpc.Core.Interceptors.ClientInterceptorContext{TRequest, TResponse}"/>
+        /// instance to pass to the next step in the invocation process.
+        /// </param>
+        public delegate AsyncUnaryCall<TResponse> AsyncUnaryCallContinuation<TRequest, TResponse>(TRequest request, ClientInterceptorContext<TRequest, TResponse> context)
+            where TRequest : class
+            where TResponse : class;
+
+        /// <summary>
+        /// Represents a continuation for intercepting asynchronous server-streaming invocations.
+        /// </summary>
+        /// <typeparam name="TRequest">Request message type for this invocation.</typeparam>
+        /// <typeparam name="TResponse">Response message type for this invocation.</typeparam>
+        /// <param name="request">The request value to continue the invocation with.</param>
+        /// <param name="context">
+        /// The <see cref="Grpc.Core.Interceptors.ClientInterceptorContext{TRequest, TResponse}"/>
+        /// instance to pass to the next step in the invocation process.
+        /// </param>
+        public delegate AsyncServerStreamingCall<TResponse> AsyncServerStreamingCallContinuation<TRequest, TResponse>(TRequest request, ClientInterceptorContext<TRequest, TResponse> context)
+            where TRequest : class
+            where TResponse : class;
+
+        /// <summary>
+        /// Represents a continuation for intercepting asynchronous client-streaming invocations.
+        /// </summary>
+        /// <typeparam name="TRequest">Request message type for this invocation.</typeparam>
+        /// <typeparam name="TResponse">Response message type for this invocation.</typeparam>
+        /// <param name="context">
+        /// The <see cref="Grpc.Core.Interceptors.ClientInterceptorContext{TRequest, TResponse}"/>
+        /// instance to pass to the next step in the invocation process.
+        /// </param>
+        public delegate AsyncClientStreamingCall<TRequest, TResponse> AsyncClientStreamingCallContinuation<TRequest, TResponse>(ClientInterceptorContext<TRequest, TResponse> context)
+            where TRequest : class
+            where TResponse : class;
+
+        /// <summary>
+        /// Represents a continuation for intercepting asynchronous duplex invocations.
+        /// </summary>
+        /// <param name="context">
+        /// The <see cref="Grpc.Core.Interceptors.ClientInterceptorContext{TRequest, TResponse}"/>
+        /// instance to pass to the next step in the invocation process.
+        /// </param>
+        public delegate AsyncDuplexStreamingCall<TRequest, TResponse> AsyncDuplexStreamingCallContinuation<TRequest, TResponse>(ClientInterceptorContext<TRequest, TResponse> context)
+            where TRequest : class
+            where TResponse : class;
+
+        /// <summary>
+        /// Intercepts a blocking invocation of a simple remote call.
+        /// </summary>
+        /// <param name="request">The request message of the invocation.</param>
+        /// <param name="context">
+        /// The <see cref="Grpc.Core.Interceptors.ClientInterceptorContext{TRequest, TResponse}"/>
+        /// associated with the current invocation.
+        /// </param>
+        /// <param name="continuation">
+        /// The callback that continues the invocation process.
+        /// This can be invoked zero or more times by the interceptor.
+        /// </param>
+        /// <returns>The response message of the current invocation.</returns>
+        public virtual TResponse BlockingUnaryCall<TRequest, TResponse>(TRequest request, ClientInterceptorContext<TRequest, TResponse> context, BlockingUnaryCallContinuation<TRequest, TResponse> continuation)
+            where TRequest : class
+            where TResponse : class
+        {
+            return continuation(request, context);
+        }
+
+        /// <summary>
+        /// Intercepts an asynchronous invocation of a simple remote call.
+        /// </summary>
+        /// <param name="request">The request message of the invocation.</param>
+        /// <param name="context">
+        /// The <see cref="Grpc.Core.Interceptors.ClientInterceptorContext{TRequest, TResponse}"/>
+        /// associated with the current invocation.
+        /// </param>
+        /// <param name="continuation">
+        /// The callback that continues the invocation process.
+        /// This can be invoked zero or more times by the interceptor.
+        /// </param>
+        public virtual AsyncUnaryCall<TResponse> AsyncUnaryCall<TRequest, TResponse>(TRequest request, ClientInterceptorContext<TRequest, TResponse> context, AsyncUnaryCallContinuation<TRequest, TResponse> continuation)
+            where TRequest : class
+            where TResponse : class
+        {
+            return continuation(request, context);
+        }
+
+        /// <summary>
+        /// Intercepts an asynchronous invocation of a streaming remote call.
+        /// </summary>
+        /// <param name="request">The request message of the invocation.</param>
+        /// <param name="context">
+        /// The <see cref="Grpc.Core.Interceptors.ClientInterceptorContext{TRequest, TResponse}"/>
+        /// associated with the current invocation.
+        /// </param>
+        /// <param name="continuation">
+        /// The callback that continues the invocation process.
+        /// This can be invoked zero or more times by the interceptor.
+        /// </param>
+        public virtual AsyncServerStreamingCall<TResponse> AsyncServerStreamingCall<TRequest, TResponse>(TRequest request, ClientInterceptorContext<TRequest, TResponse> context, AsyncServerStreamingCallContinuation<TRequest, TResponse> continuation)
+            where TRequest : class
+            where TResponse : class
+        {
+            return continuation(request, context);
+        }
+
+        /// <summary>
+        /// Intercepts an asynchronous invocation of a client streaming call.
+        /// </summary>
+        /// <param name="context">
+        /// The <see cref="Grpc.Core.Interceptors.ClientInterceptorContext{TRequest, TResponse}"/>
+        /// associated with the current invocation.
+        /// </param>
+        /// <param name="continuation">
+        /// The callback that continues the invocation process.
+        /// This can be invoked zero or more times by the interceptor.
+        /// </param>
+        public virtual AsyncClientStreamingCall<TRequest, TResponse> AsyncClientStreamingCall<TRequest, TResponse>(ClientInterceptorContext<TRequest, TResponse> context, AsyncClientStreamingCallContinuation<TRequest, TResponse> continuation)
+            where TRequest : class
+            where TResponse : class
+        {
+            return continuation(context);
+        }
+
+        /// <summary>
+        /// Intercepts an asynchronous invocation of a duplex streaming call.
+        /// </summary>
+        /// <param name="context">
+        /// The <see cref="Grpc.Core.Interceptors.ClientInterceptorContext{TRequest, TResponse}"/>
+        /// associated with the current invocation.
+        /// </param>
+        /// <param name="continuation">
+        /// The callback that continues the invocation process.
+        /// This can be invoked zero or more times by the interceptor.
+        /// </param>
+        public virtual AsyncDuplexStreamingCall<TRequest, TResponse> AsyncDuplexStreamingCall<TRequest, TResponse>(ClientInterceptorContext<TRequest, TResponse> context, AsyncDuplexStreamingCallContinuation<TRequest, TResponse> continuation)
+            where TRequest : class
+            where TResponse : class
+        {
+            return continuation(context);
+        }
+
+        /// <summary>
+        /// Server-side handler for intercepting unary calls.
+        /// </summary>
+        /// <typeparam name="TRequest">Request message type for this method.</typeparam>
+        /// <typeparam name="TResponse">Response message type for this method.</typeparam>
+        public virtual Task<TResponse> UnaryServerHandler<TRequest, TResponse>(TRequest request, ServerCallContext context, UnaryServerMethod<TRequest, TResponse> continuation)
+            where TRequest : class
+            where TResponse : class
+        {
+            return continuation(request, context);
+        }
+
+        /// <summary>
+        /// Server-side handler for intercepting client streaming call.
+        /// </summary>
+        /// <typeparam name="TRequest">Request message type for this method.</typeparam>
+        /// <typeparam name="TResponse">Response message type for this method.</typeparam>
+        public virtual Task<TResponse> ClientStreamingServerHandler<TRequest, TResponse>(IAsyncStreamReader<TRequest> requestStream, ServerCallContext context, ClientStreamingServerMethod<TRequest, TResponse> continuation)
+            where TRequest : class
+            where TResponse : class
+        {
+            return continuation(requestStream, context);
+        }
+
+        /// <summary>
+        /// Server-side handler for intercepting server streaming calls.
+        /// </summary>
+        /// <typeparam name="TRequest">Request message type for this method.</typeparam>
+        /// <typeparam name="TResponse">Response message type for this method.</typeparam>
+        public virtual Task ServerStreamingServerHandler<TRequest, TResponse>(TRequest request, IServerStreamWriter<TResponse> responseStream, ServerCallContext context, ServerStreamingServerMethod<TRequest, TResponse> continuation)
+            where TRequest : class
+            where TResponse : class
+        {
+            return continuation(request, responseStream, context);
+        }
+
+        /// <summary>
+        /// Server-side handler for intercepting bidi streaming calls.
+        /// </summary>
+        /// <typeparam name="TRequest">Request message type for this method.</typeparam>
+        /// <typeparam name="TResponse">Response message type for this method.</typeparam>
+        public virtual Task DuplexStreamingServerHandler<TRequest, TResponse>(IAsyncStreamReader<TRequest> requestStream, IServerStreamWriter<TResponse> responseStream, ServerCallContext context, DuplexStreamingServerMethod<TRequest, TResponse> continuation)
+            where TRequest : class
+            where TResponse : class
+        {
+            return continuation(requestStream, responseStream, context);
+        }
+    }
+}