public void CleanupMessagingResources(string correlationId, ExpectedResponse expectedResponse)
{
if (expectedResponse != null)
{
expectedResponse.Dispose();
}
}
public ExpectedResponse PrepareForResponse(string correlationId, BasicProperties basicProperties, AmqpModelContainer model, HttpRequestMessage request, TimeSpan requestTimeout, CancellationToken cancellationToken, TaskCompletionSource <HttpResponseMessage> taskSource)
{
//Set Reply to queue
basicProperties.ReplyTo = RPCStrategyHelpers.DIRECT_REPLY_TO_QUEUENAME_ARG;
var rpcModel = (RPCModelContainer)model;
var arrival = new ExpectedResponse(rpcModel.ReceivedResponseEvent);
rpcModel.ExpectResponse(correlationId, arrival);
RPCStrategyHelpers.WaitForResponse(request, arrival, requestTimeout, model, true, cancellationToken, taskSource, () => CleanupMessagingResources(correlationId, arrival));
return(arrival);
}
public void CleanupMessagingResources(string correlationId, ExpectedResponse expectedResponse)
{
if (!String.IsNullOrEmpty(correlationId))
{
ExpectedResponse unused;
expectedResponses.TryRemove(correlationId, out unused);
}
if (expectedResponse != null)
{
expectedResponse.Dispose();
}
}
public ExpectedResponse PrepareForResponse(string correlationId, BasicProperties basicProperties, AmqpModelContainer model, HttpRequestMessage request, TimeSpan requestTimeout, CancellationToken cancellationToken, TaskCompletionSource <HttpResponseMessage> taskSource)
{
//Set Reply to queue
basicProperties.ReplyTo = callbackQueueName;
//Initialize response arrival object and add to expected responses dictionary
var arrival = new ExpectedResponse();
expectedResponses[correlationId] = arrival;
RPCStrategyHelpers.WaitForResponse(request, arrival, requestTimeout, model, false, cancellationToken, taskSource, () => CleanupMessagingResources(correlationId, arrival));
return(arrival);
}
internal static void ReadAndSignalDelivery(ExpectedResponse expected, BasicDeliverEventArgs evt)
{
try
{
expected.Response = HttpResponsePacket.Deserialize(evt.Body);
}
catch (Exception ex)
{
expected.DeserializationException = ex;
}
//NOTE: The ManualResetEventSlim.Set() method can be called after the object has been disposed
//So no worries about the Timeout disposing the object before the response comes in.
expected.ReceivedEvent.Set();
}
internal static void WaitForResponse(HttpRequestMessage request, ExpectedResponse arrival, TimeSpan requestTimeout, AmqpModelContainer model, bool closeModel, CancellationToken cancellationToken, TaskCompletionSource <HttpResponseMessage> taskSource, Action cleanup)
{
var localVariableInitLock = new object();
lock (localVariableInitLock)
{
//TODO: Have cancellationToken signal WaitHandle so that threadpool stops waiting.
RegisteredWaitHandle callbackHandle = null;
callbackHandle = ThreadPool.RegisterWaitForSingleObject(arrival.ReceivedEvent.WaitHandle,
(state, timedOut) =>
{
//TODO: Investigate, this memorybarrier might be unnecessary since the thread is released from the threadpool
//after deserializationException and responsePacket is set.
Interlocked.MemoryBarrier(); //Ensure non-cached versions of arrival are read
try
{
//TODO: Check Cancelation Token when it's implemented
if (closeModel)
{
model.Close();
}
SetResponseResult(request, timedOut, arrival, taskSource);
lock (localVariableInitLock)
{
callbackHandle.Unregister(null);
}
}
catch
{
//TODO: Log this:
// the code in the try block should be safe so this catch block should never be called,
// hoewever, this delegate is called on a separate thread and should be protected.
}
finally
{
cleanup();
}
},
null,
requestTimeout == System.Threading.Timeout.InfiniteTimeSpan ? System.Threading.Timeout.Infinite : (long)requestTimeout.TotalMilliseconds,
true);
}
}
/// <summary>Send an HTTP request as an asynchronous operation.</summary>
/// <returns>Returns <see cref="T:System.Threading.Tasks.Task`1" />.The task object representing the asynchronous operation.</returns>
/// <param name="request">The HTTP request message to send.</param>
/// <param name="cancellationToken">The cancellation token to cancel operation.</param>
/// <exception cref="T:System.ArgumentNullException">The <paramref name="request" /> was null.</exception>
public override Task <HttpResponseMessage> SendAsync(HttpRequestMessage request, System.Threading.CancellationToken cancellationToken)
{
if (request == null)
{
throw new ArgumentNullException("request");
}
if (request.RequestUri == null && BaseAddress == null)
{
throw new InvalidOperationException("The request URI must either be set or BaseAddress must be set");
}
if (disposed)
{
throw new ObjectDisposedException(GetType().FullName);
}
hasKickStarted = true;
PrepareMessage(request);
//Get Request Options
RequestOptions requestOptions = GetRequestOptions(request);
var messageProperties = GetMessagingProperties(requestOptions);
//Determine if message expects a response
TimeSpan requestTimeout = GetRequestTimeout(requestOptions);
//TODO: expectingResponse has a slightly different meaning in publisher confirms
//where timespan may be longer than zero but MessageExpectsReply is false
//in which case the timeout only applies to how long to wait for the publisher confirmation.
bool expectingResponse = requestTimeout != TimeSpan.Zero && GetExpectsReply(request);
//Declare messaging resources
ExpectedResponse arrival = null;
AmqpModelContainer model = null;
bool modelClosed = false;
string correlationId = null;
//Get channel pool and decide on RPC strategy
var pool = connectionMgr.GetConnectedPool();
IRPCStrategy rpcStrategy = pool.IsDirectReplyToCapable && !Settings.DisableDirectReplies ? directStrategy : callbackStrategy;
try
{
#region Ensure CallbackQueue is started (If Using CallbackQueue Strategy)
rpcStrategy.StartStrategy(pool, expectingResponse);
#endregion
#region Populate BasicProperties
//Fill BasicProperties
BasicProperties basicProperties = new BasicProperties();
//Set message delivery mode -- Make message persistent if either:
// 1. Properties.Persistent is true
// 2. messagingConfig.PersistentMessages is true and Properties.Persistent is null
// 3. messagingConfig.PersistentMessages is true and Properties.Persistent is true
if (messageProperties.Persistent == true || (messagingConfig.PersistentMessages && messageProperties.Persistent != false))
{
basicProperties.Persistent = true;
}
//Set Exchange Headers
var exchangeHeaders = messageProperties.Headers ?? messageMapper.GetHeaders(request);
if (exchangeHeaders != null)
{
basicProperties.Headers = exchangeHeaders;
}
if (expectingResponse)
{
//Set CorrelationId
correlationId = correlationIdGen.GetNextId();
basicProperties.CorrelationId = correlationId;
//Set Expiration if messageProperties doesn't override Client.Timeout, RequestOptions and MessageMapper.
if (!messageProperties.Expiration.HasValue && requestTimeout != System.Threading.Timeout.InfiniteTimeSpan &&
(messagingConfig.MessageExpires == null || messagingConfig.MessageExpires(request)))
{
if (requestTimeout.TotalMilliseconds > Int32.MaxValue)
{
basicProperties.Expiration = Int32.MaxValue.ToString();
}
else
{
basicProperties.Expiration = ((int)requestTimeout.TotalMilliseconds).ToString();
}
}
}
else if (!messageProperties.Expiration.HasValue && (messagingConfig.MessageExpires == null || messagingConfig.MessageExpires(request)))
{
//Request has a zero timeout and the message mapper indicates it should expire and messageproperties expiration is not set:
//Set the expiration to zero which means RabbitMQ will only transmit if there is a consumer ready to receive it.
//If there is no ready consumer, RabbitMQ drops the message. See https://www.rabbitmq.com/ttl.html
basicProperties.Expiration = "0";
}
//Set expiration if set in message properties
if (messageProperties.Expiration.HasValue)
{
if (messageProperties.Expiration != System.Threading.Timeout.InfiniteTimeSpan)
{
var expiration = messageProperties.Expiration.Value.Duration();
if (expiration.TotalMilliseconds > Int32.MaxValue)
{
basicProperties.Expiration = Int32.MaxValue.ToString();
}
else
{
basicProperties.Expiration = ((int)expiration.TotalMilliseconds).ToString();
}
}
else
{
//Infinite Timespan indicates that message should never expire
basicProperties.ClearExpiration();
}
}
#endregion
#region Get Ready to Send Message
model = rpcStrategy.GetModel(pool, false);
var serviceName =
(requestOptions == null || requestOptions.ServiceName == null)
? (messageMapper.GetServiceName(request) ?? String.Empty).Trim()
: requestOptions.ServiceName.Trim();
RedeclareExchangesAndQueues(model, serviceName);
//TODO: Check if cancellation token was set before operation even began
var taskSource = new TaskCompletionSource <HttpResponseMessage>();
var exchangeKind = ExchangeKind.Direct;
//TODO: Get ExchangeKind from CLient.Settings.ExchangeKind
//TODO: Pull exchangeName from a concurrent dictionary that has a key of serviceName, exchangeKind
//exchangeKind could be an index into arrays that have concurrentDictionaries.
var exchangeName = AmqpUtils.GetExchangeName(messagingConfig, serviceName, exchangeKind);
#endregion
#region Start waiting for response
//Start waiting for response if a request timeout is set.
if (expectingResponse)
{
//TODO: Better to just check if cancellationHasbeen requested instead of checking if it's None
if (!cancellationToken.Equals(System.Threading.CancellationToken.None))
{
//TODO: Have cancellationtokens cancel event trigger callbackHandle
//In fact turn this whole thing into an extension
}
arrival = rpcStrategy.PrepareForResponse(correlationId, basicProperties, model, request, requestTimeout, cancellationToken, taskSource);
}
#endregion
#region Send Message
//TODO: Implement routing to a different exchangeKind via substituting exchangeName
//Send message
model.Channel.BasicPublish(exchangeName,
messageProperties.RoutingKey ?? messageMapper.GetRoutingKey(request, exchangeKind) ?? AmqpUtils.GetWorkQueueRoutingKey(),
basicProperties,
request.ToHttpRequestPacket().Serialize());
//Close channel
if (!expectingResponse || rpcStrategy.ReturnModelAfterSending)
{
CloseAmqpModel(model);
modelClosed = true;
}
#endregion
#region Cleanup if not expecting response
//Exit with OK result if no request timeout was set.
if (!expectingResponse)
{
//TODO: Investigate adding a publisher confirm for zero timeout messages so we know that RabbitMQ did pick up the message before replying OK.
//Might add extra complexity to this class.
//Zero timespan means the client isn't interested in a response
taskSource.SetResult(new HttpResponseMessage(System.Net.HttpStatusCode.OK)
{
Content = _emptyByteArrayContent
});
rpcStrategy.CleanupMessagingResources(correlationId, arrival);
}
#endregion
return(taskSource.Task);
}
catch (Exception ex)
{
//TODO: Log this
if (model != null && !modelClosed)
{
if (expectingResponse && model.Flags == ChannelFlags.RPC || model.Flags == ChannelFlags.RPCWithPublisherConfirms)
{
//Model might still be in use in waiting thread and so unsafe to be recycled
model.Discard = true;
}
CloseAmqpModel(model);
}
rpcStrategy.CleanupMessagingResources(correlationId, arrival);
if (ex is HttpRequestException)
{
throw;
}
else
{
throw GetWrappedException("An error occurred while sending the request.", ex);
}
}
}
private static void SetResponseResult(HttpRequestMessage request, bool timedOut, ExpectedResponse arrival, TaskCompletionSource <HttpResponseMessage> taskSource)
{
if (timedOut)
{
taskSource.SetCanceled();
}
else
{
if (arrival.DeserializationException == null)
{
if (arrival.Response == null)
{
//TODO: Log this -- Critical issue (or just assert)
}
}
HttpResponseMessage msg;
if (arrival.DeserializationException == null && TryGetHttpResponseMessage(arrival.Response, out msg))
{
msg.RequestMessage = request;
taskSource.SetResult(msg);
}
else
{
taskSource.SetException(RestBusClient.GetWrappedException("An error occurred while reading the response.", arrival.DeserializationException));
}
}
}