使用C＃.Net WCF Rest服务访问IBM MQ消息

Question

Unable to retrieve the first response message from IBM MQ.

I have designed the IBM MQ connection, message passing and message retrieval in a ASP.NET web application which is working perfectly fine. When I try to implement the same logic in a WCF REST service, the very first request will always return error in .net as 'MQRC_NO_MSG_AVAIL'. However when I will pass the second request I will receive the response for first request The error in IBM MQ for first request is

Message . . . . : Error on receive from host 10 (XXX.XXX.XX).
Cause . . . . . : An error occurred receiving data from 10 (XXX.XXX.XX) over TCP/IP. This may be due to a communications failure. Recovery . . . : The return code from the TCP/IP (read) call was 3426 (X'X'00000D62''). Record these values and tell the systems administrator.

The request openOptions :

MQC.MQOO_INPUT_AS_Q_DEF + MQC.MQOO_FAIL_IF_QUIESCING + MQC.MQOO_OUTPUT The response openOptions : MQC.MQOO_INQUIRE + MQC.MQOO_BROWSE + MQC.MQOO_FAIL_IF_QUIESCING + MQC.MQOO_INPUT_SHARED

Note : When I tried to check in IBM MQ Explorer the first request response always goes into 'Current QueueDepth' .Current QueueDepth doesnot get blank when I have read the response the second time. We have separate queues for Input and Output We tried restarting the IBM MQ ,clearing messages,creating new queue and new channel but nothing works.

ReadMsg method :

queue = queueManager.AccessQueue(queueName, MQC.MQOO_INQUIRE + MQC.MQOO_BROWSE + MQC.MQOO_FAIL_IF_QUIESCING + MQC.MQOO_INPUT_SHARED );
queueMessage = new MQMessage();
queueMessage.Format = MQC.MQFMT_STRING;
queueGetMessageOptions = new MQGetMessageOptions();
queue.Get(queueMessage, queueGetMessageOptions);
strReturn = queueMessage.ReadString(queueMessage.MessageLength);

Answer 1

The issue has been resolved.

Reason : When the first request was sent the connection was already existing for that message and read operation could not read the output as the response was already held by previous(write) object. When I was sending second request, the first connection was disconnected so I was able to read the response of first request.

Solution : After completing the write operation i used 'queueManager.Disconnect()'. However I had to reestablish the connection when reading the message from queue.

The connection code:
System.Collections.Hashtable queueProperties = new System.Collections.Hashtable();
queueProperties[MQC.HOST_NAME_PROPERTY] = host;
queueProperties[MQC.PORT_PROPERTY] = port;
queueProperties[MQC.CHANNEL_PROPERTY] = channel;            
queueManager = new MQQueueManager(queueManagerName, queueProperties);                

The write code:
queue = queueManager.AccessQueue(queueName, MQC.MQOO_INPUT_SHARED + MQC.MQOO_FAIL_IF_QUIESCING + MQC.MQOO_OUTPUT + MQC.MQOO_BROWSE);                
queueMessage = new MQMessage();
queueMessage.WriteString(message);
queueMessage.Persistence = 0;
queueMessage.Format = MQC.MQFMT_STRING;
queuePutMessageOptions = new MQPutMessageOptions();
queue.Put(queueMessage, queuePutMessageOptions);
queueManager.Disconnect();
queue.Close(); 

The read code :
queue = queueManager.AccessQueue(queueName, MQC.MQOO_INQUIRE + MQC.MQOO_BROWSE + MQC.MQOO_FAIL_IF_QUIESCING + MQC.MQOO_INPUT_SHARED + MQC.MQCMD_CREATE_LISTENER);
queueMessage.Format = MQC.MQFMT_STRING;
queueGetMessageOptions = new MQGetMessageOptions();
queue.Get(queueMessage, queueGetMessageOptions);
strReturn = queueMessage.ReadString(queueMessage.MessageLength);
queueManager.Disconnect();
queue.Close();

Method calling:

Write:
connectResp = operation.ConnectMQ(CustomMQ.queueManager, CustomMQ.host, CustomMQ.port, CustomMQ.channel);
sendResp = operation.WriteQMsg(CustomMQ.inputQueueName, request);

Read:
connectResp = operation.ConnectMQ(CustomMQ.queueManager, CustomMQ.host, CustomMQ.port, CustomMQ.channel);
response = operation.ReadQMsg(CustomMQ.outputQueueName);

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