Fix client to only filter known gRPC headers (#1046)

Author: JamesNK

src/Grpc.Net.Client/Internal/GrpcProtocolHelpers.cs

@@ -62,15 +62,7 @@ public static Metadata BuildMetadata(HttpResponseHeaders responseHeaders)
 
             foreach (var header in responseHeaders)
             {
-                // ASP.NET Core includes pseudo headers in the set of request headers
-                // whereas, they are not in gRPC implementations. We will filter them
-                // out when we construct the list of headers on the context.
-                if (header.Key.StartsWith(':'))
-                {
-                    continue;
-                }
-                // Exclude grpc related headers
-                if (header.Key.StartsWith("grpc-", StringComparison.OrdinalIgnoreCase))
+                if (ShouldSkipHeader(header.Key))
                 {
                     continue;
                 }
@@ -91,6 +83,32 @@ public static Metadata BuildMetadata(HttpResponseHeaders responseHeaders)
             return headers;
         }
 
+        internal static bool ShouldSkipHeader(string name)
+        {
+            if (name.Length == 0)
+            {
+                return false;
+            }
+
+            switch (name[0])
+            {
+                case ':':
+                    // ASP.NET Core includes pseudo headers in the set of request headers
+                    // whereas, they are not in gRPC implementations. We will filter them
+                    // out when we construct the list of headers on the context.
+                    return true;
+                case 'g':
+                case 'G':
+                    // Exclude known grpc headers. This matches Grpc.Core client behavior.
+                    return string.Equals(name, GrpcProtocolConstants.StatusTrailer, StringComparison.OrdinalIgnoreCase)
+                        || string.Equals(name, GrpcProtocolConstants.MessageTrailer, StringComparison.OrdinalIgnoreCase)
+                        || string.Equals(name, GrpcProtocolConstants.MessageEncodingHeader, StringComparison.OrdinalIgnoreCase)
+                        || string.Equals(name, GrpcProtocolConstants.MessageAcceptEncodingHeader, StringComparison.OrdinalIgnoreCase);
+                default:
+                    return false;
+            }
+        }
+
         private const int MillisecondsPerSecond = 1000;
 
         /* round an integer up to the next value with three significant figures */

test/FunctionalTests/Client/TrailerMetadataTests.cs

@@ -17,6 +17,7 @@
 #endregion
 
 using System.Linq;
+using System.Text;
 using System.Threading.Tasks;
 using Greet;
 using Grpc.AspNetCore.FunctionalTests.Infrastructure;
@@ -35,6 +36,7 @@ public async Task GetTrailers_UnaryMethodSetStatusWithTrailers_TrailersAvailable
             Task<HelloReply> UnaryDeadlineExceeded(HelloRequest request, ServerCallContext context)
             {
                 context.ResponseTrailers.Add(new Metadata.Entry("Name", "the value was empty"));
+                context.ResponseTrailers.Add(new Metadata.Entry("grpc-status-details-bin", Encoding.UTF8.GetBytes("Hello world")));
                 context.Status = new Status(StatusCode.InvalidArgument, "Validation failed");
                 return Task.FromResult(new HelloReply());
             }
@@ -65,13 +67,15 @@ Task<HelloReply> UnaryDeadlineExceeded(HelloRequest request, ServerCallContext c
 
             // Assert
             var trailers = call.GetTrailers();
-            Assert.AreEqual(1, trailers.Count);
+            Assert.AreEqual(2, trailers.Count);
             Assert.AreEqual("the value was empty", trailers.GetValue("name"));
+            Assert.AreEqual("Hello world", Encoding.UTF8.GetString(trailers.GetValueBytes("grpc-status-details-bin")));
 
             Assert.AreEqual(StatusCode.InvalidArgument, ex.StatusCode);
             Assert.AreEqual("Validation failed", ex.Status.Detail);
-            Assert.AreEqual(1, ex.Trailers.Count);
+            Assert.AreEqual(2, ex.Trailers.Count);
             Assert.AreEqual("the value was empty", ex.Trailers.GetValue("name"));
+            Assert.AreEqual("Hello world", Encoding.UTF8.GetString(ex.Trailers.GetValueBytes("grpc-status-details-bin")));
         }
 
         [Test]
@@ -81,6 +85,7 @@ Task<HelloReply> UnaryDeadlineExceeded(HelloRequest request, ServerCallContext c
             {
                 var trailers = new Metadata();
                 trailers.Add(new Metadata.Entry("Name", "the value was empty"));
+                trailers.Add(new Metadata.Entry("grpc-status-details-bin", Encoding.UTF8.GetBytes("Hello world")));
                 return Task.FromException<HelloReply>(new RpcException(new Status(StatusCode.InvalidArgument, "Validation failed"), trailers));
             }
 
@@ -110,13 +115,15 @@ Task<HelloReply> UnaryDeadlineExceeded(HelloRequest request, ServerCallContext c
 
             // Assert
             var trailers = call.GetTrailers();
-            Assert.GreaterOrEqual(trailers.Count, 1);
+            Assert.GreaterOrEqual(trailers.Count, 2);
             Assert.AreEqual("the value was empty", trailers.GetValue("name"));
+            Assert.AreEqual("Hello world", Encoding.UTF8.GetString(trailers.GetValueBytes("grpc-status-details-bin")));
 
             Assert.AreEqual(StatusCode.InvalidArgument, ex.StatusCode);
             Assert.AreEqual("Validation failed", ex.Status.Detail);
-            Assert.GreaterOrEqual(ex.Trailers.Count, 1);
+            Assert.GreaterOrEqual(ex.Trailers.Count, 2);
             Assert.AreEqual("the value was empty", ex.Trailers.GetValue("name"));
+            Assert.AreEqual("Hello world", Encoding.UTF8.GetString(ex.Trailers.GetValueBytes("grpc-status-details-bin")));
 
             AssertHasLogRpcConnectionError(StatusCode.InvalidArgument, "Validation failed");
         }

test/Grpc.Net.Client.Tests/GrpcProtocolHelpersTests.cs

@@ -16,9 +16,7 @@
 
 #endregion
 
-using System.Net.Http.Headers;
 using Grpc.Net.Client.Internal;
-using Grpc.Shared;
 using NUnit.Framework;
 
 namespace Grpc.Net.Client.Tests
@@ -54,5 +52,24 @@ public void EncodeTimeout(int milliseconds, string expected)
             var encoded = GrpcProtocolHelpers.EncodeTimeout(milliseconds);
             Assert.AreEqual(expected, encoded);
         }
+
+        [TestCase(":status", true)]
+        [TestCase(":STATUS", true)]
+        [TestCase("grpc-status", true)]
+        [TestCase("GRPC-STATUS", true)]
+        [TestCase("grpc-message", true)]
+        [TestCase("GRPC-MESSAGE", true)]
+        [TestCase("grpc-encoding", true)]
+        [TestCase("GRPC-ENCODING", true)]
+        [TestCase("grpc-accept-encoding", true)]
+        [TestCase("GRPC-ACCEPT-ENCODING", true)]
+        [TestCase("custom", false)]
+        [TestCase("grpc-status-details-bin", false)]
+        [TestCase("GRPC-STATUS-DETAILS-BIN", false)]
+        public void ShouldSkipHeader(string header, bool skipped)
+        {
+            var result = GrpcProtocolHelpers.ShouldSkipHeader(header);
+            Assert.AreEqual(skipped, result);
+        }
     }
 }