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Fixing a bug where cancellation could result in HubException 

When the client cancels a streaming method the server would send an error completion. This was not correct because cancellation is not an error. We did not see this because our client ignores any messages for a given streaming invocation after sending a CancelInvokationMessage but other clients may want to drain messages before considering a streaming method canceled.
This commit is contained in:
Pawel Kadluczka 2017-10-25 13:51:43 -07:00 committed by Pawel Kadluczka
parent 8c446fc02d
commit cc42b0eaef
2 changed files with 44 additions and 6 deletions
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18
src/Microsoft.AspNetCore.SignalR.Core/HubEndPoint.cs
View File

@ -46,7 +46,7 @@ namespace Microsoft.AspNetCore.SignalR
IHubContext<THub> hubContext,
IOptions<HubOptions> hubOptions,
ILogger<HubEndPoint<THub>> logger,
IServiceScopeFactory serviceScopeFactory,
IServiceScopeFactory serviceScopeFactory,
IUserIdProvider userIdProvider)
{
_protocolResolver = protocolResolver;
@ -282,7 +282,8 @@ namespace Microsoft.AspNetCore.SignalR
case CancelInvocationMessage cancelInvocationMessage:
// Check if there is an associated active stream and cancel it if it exists.
if (connection.ActiveRequestCancellationSources.TryRemove(cancelInvocationMessage.InvocationId, out var cts))
// The cts will be removed when the streaming method completes executing
if (connection.ActiveRequestCancellationSources.TryGetValue(cancelInvocationMessage.InvocationId, out var cts))
{
_logger.CancelStream(cancelInvocationMessage.InvocationId);
cts.Cancel();
@ -464,6 +465,8 @@ namespace Microsoft.AspNetCore.SignalR
private async Task StreamResultsAsync(string invocationId, HubConnectionContext connection, IAsyncEnumerator<object> enumerator)
{
string error = null;
try
{
while (await enumerator.MoveNextAsync())
@ -471,15 +474,20 @@ namespace Microsoft.AspNetCore.SignalR
// Send the stream item
await SendMessageAsync(connection, new StreamItemMessage(invocationId, enumerator.Current));
}
await SendMessageAsync(connection, new StreamCompletionMessage(invocationId, error: null));
}
catch (Exception ex)
{
await SendMessageAsync(connection, new StreamCompletionMessage(invocationId, error: ex.Message));
// If the streaming method was canceled we don't want to send a HubException message - this is not an error case
if (!(ex is OperationCanceledException && connection.ActiveRequestCancellationSources.TryGetValue(invocationId, out var cts)
&& cts.IsCancellationRequested))
{
error = ex.Message;
}
}
finally
{
await SendMessageAsync(connection, new StreamCompletionMessage(invocationId, error: error));
if (connection.ActiveRequestCancellationSources.TryRemove(invocationId, out var cts))
{
cts.Dispose();

32
test/Microsoft.AspNetCore.SignalR.Tests/HubEndpointTests.cs
View File

@ -132,7 +132,6 @@ namespace Microsoft.AspNetCore.SignalR.Tests
client.Dispose();
// We don't care if this throws, we just expect it to complete
try
{
@ -1024,6 +1023,32 @@ namespace Microsoft.AspNetCore.SignalR.Tests
}
}
[Fact]
public async Task NonErrorCompletionSentWhenStreamCanceledFromClient()
{
var serviceProvider = CreateServiceProvider();
var endPoint = serviceProvider.GetService<HubEndPoint<StreamingHub>>();
using (var client = new TestClient())
{
var endPointLifetime = endPoint.OnConnectedAsync(client.Connection);
await client.Connected.OrTimeout();
var invocationId = await client.SendInvocationAsync(nameof(StreamingHub.BlockingStream)).OrTimeout();
// cancel the Streaming method
await client.SendHubMessageAsync(new CancelInvocationMessage(invocationId)).OrTimeout();
var hubMessage = Assert.IsType<StreamCompletionMessage>(await client.ReadAsync().OrTimeout());
Assert.Equal(invocationId, hubMessage.InvocationId);
Assert.Null(hubMessage.Error);
client.Dispose();
await endPointLifetime.OrTimeout();
}
}
public static IEnumerable<object[]> StreamingMethodAndHubProtocols
{
get
@ -1587,6 +1612,11 @@ namespace Microsoft.AspNetCore.SignalR.Tests
return channel.In;
}
public ReadableChannel<string> BlockingStream()
{
return Channel.CreateUnbounded<string>().In;
}
private class CountingObservable : IObservable<string>
{
private int _count;