implemented cancellation support for MathService.Fib

2 files changed, 40 insertions, 2 deletions

diff --git a/src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs b/src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs
index 7a957c5b6f..6edc07912b 100644
--- a/src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs
+++ b/src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs
@@ -132,6 +132,39 @@ namespace math.Tests
             }).Wait();
         }
 
+        [Test]
+        public void FibWithCancel()
+        {
+            Task.Run(async () =>
+            {
+                var cts = new CancellationTokenSource();
+
+                using (var call = client.Fib(new FibArgs.Builder { Limit = 0 }.Build(), 
+                    cancellationToken: cts.Token))
+                {
+                    List<long> responses = new List<long>();
+
+                    try
+                    {
+                        while (await call.ResponseStream.MoveNext())
+                        {
+                            if (responses.Count == 0)
+                            {
+                                cts.CancelAfter(500);  // make sure we cancel soon
+                            }
+                            responses.Add(call.ResponseStream.Current.Num_);
+                        }
+                        Assert.Fail();
+                    }
+                    catch (RpcException e)
+                    {
+                        Assert.IsTrue(responses.Count > 0);
+                        Assert.AreEqual(StatusCode.Cancelled, e.Status.StatusCode);
+                    }
+                }
+            }).Wait();
+        }
+
         // TODO: test Fib with limit=0 and cancellation
         [Test]
         public void Sum()
diff --git a/src/csharp/Grpc.Examples/MathServiceImpl.cs b/src/csharp/Grpc.Examples/MathServiceImpl.cs
index 3dd0f53a0d..dd26b1d350 100644
--- a/src/csharp/Grpc.Examples/MathServiceImpl.cs
+++ b/src/csharp/Grpc.Examples/MathServiceImpl.cs
@@ -54,8 +54,13 @@ namespace math
         {
             if (request.Limit <= 0)
             {
-                // TODO(jtattermusch): support cancellation
-                throw new NotImplementedException("Not implemented yet");
+                // keep streaming the sequence until cancelled.
+                IEnumerator<Num> fibEnumerator = FibInternal(long.MaxValue).GetEnumerator();
+                while (!context.CancellationToken.IsCancellationRequested && fibEnumerator.MoveNext())
+                {
+                    await responseStream.WriteAsync(fibEnumerator.Current);
+                    await Task.Delay(100);
+                }
             }
 
             if (request.Limit > 0)