Initial checkin of gRPC to third_party/

third_party/grpc/src/csharp/Grpc.Auth/GoogleAuthInterceptors.cs

+#region Copyright notice and license
+
+// Copyright 2015-2016, 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;
+
+using Google.Apis.Auth.OAuth2;
+using Grpc.Core;
+using Grpc.Core.Utils;
+
+namespace Grpc.Auth
+{
+    /// <summary>
+    /// Factory methods to create authorization interceptors for Google credentials.
+    /// <seealso cref="GoogleGrpcCredentials"/>
+    /// </summary>
+    public static class GoogleAuthInterceptors
+    {
+        private const string AuthorizationHeader = "Authorization";
+        private const string Schema = "Bearer";
+
+        /// <summary>
+        /// Creates an <see cref="AsyncAuthInterceptor"/> that will obtain access token from any credential type that implements
+        /// <c>ITokenAccess</c>. (e.g. <c>GoogleCredential</c>).
+        /// </summary>
+        /// <param name="credential">The credential to use to obtain access tokens.</param>
+        /// <returns>The interceptor.</returns>
+        public static AsyncAuthInterceptor FromCredential(ITokenAccess credential)
+        {
+            return new AsyncAuthInterceptor(async (context, metadata) =>
+            {
+                var accessToken = await credential.GetAccessTokenForRequestAsync(context.ServiceUrl, CancellationToken.None).ConfigureAwait(false);
+                metadata.Add(CreateBearerTokenHeader(accessToken));
+            });
+        }
+
+        /// <summary>
+        /// Creates an <see cref="AsyncAuthInterceptor"/> that will use given access token as authorization.
+        /// </summary>
+        /// <param name="accessToken">OAuth2 access token.</param>
+        /// <returns>The interceptor.</returns>
+        public static AsyncAuthInterceptor FromAccessToken(string accessToken)
+        {
+            GrpcPreconditions.CheckNotNull(accessToken);
+            return new AsyncAuthInterceptor(async (context, metadata) =>
+            {
+                metadata.Add(CreateBearerTokenHeader(accessToken));
+            });
+        }
+
+        private static Metadata.Entry CreateBearerTokenHeader(string accessToken)
+        {
+            return new Metadata.Entry(AuthorizationHeader, Schema + " " + accessToken);
+        }
+    }
+}