REQ.PROD and RESP.PROD messages do not work with GMSEC Connection "request/reply" API

[pmccauley1]

Environment: Java/Windows

When attempting to send a REQ.PROD message using the Connection.publish API, I receive the following error:

2024-337-11:18:52.831 [ERROR] [Publisher.java:258] GmsecException: [2,7,0] : Cannot publish message with non-PUBLISH message kind.

I believe this is correct since this is a product "request/reply" message pair. However, when changing the Connection.publish call to a Connection.request, I do not receive a response message, i.e. the request call times out.

I think this is due to the REQ.PROD message not defining a RESPONSE field, which is what the GMSEC code seems to require in order to register for a response message (see call here and implementation here). Because the REQ.PROD message does not have (and does not allow) a RESPONSE field, the response callback never gets created.

Note that instead of a RESPONSE flag, the REQ.PROD message uses a RESPOND-VIA-MSG field whose values may be MSG.PROD or RESP.PROD. I think the latter needs to be considered by the GMSEC framework when creating a response listener.

[pmccauley1]

I modified the "request" and "reply" Java examples to illustrate this by using the Product messages rather than Directive messages. See attached.
req.prod.message.problem.zip

[dmwhitne-583]

This is a great find! It should be reported to gmsec-support@lists.nasa.gov.

If you need an immediate solution, you could modify the Open-Source s/w in framework/src/gmsec5/internal/InternalConnection.cpp with something like this:

git diff framework/src/gmsec5/internal/InternalConnection.cpp
diff --git a/framework/src/gmsec5/internal/InternalConnection.cpp b/framework/src/gmsec5/internal/InternalConnection.cpp
index 050e1634..a77ebe8d 100644
--- a/framework/src/gmsec5/internal/InternalConnection.cpp
+++ b/framework/src/gmsec5/internal/InternalConnection.cpp
@@ -1812,7 +1812,8 @@ void InternalConnection::initializeRequest()
 void InternalConnection::setupSubscriptionForResponse(const Message& request)
 {
        // Attempt to set up a subscription so that a response, if requested, can be delivered
-       if (request.hasField("RESPONSE") && request.getBooleanValue("RESPONSE"))
+       if ((request.hasField("RESPONSE") && request.getBooleanValue("RESPONSE")) ||
+           (request.hasField("RESPOND-VIA-MSG")))

Note, your reply_prod.java should include the following changes as well:

            // Check if we have received a message.
            if (null != reqMsg)
            {
                // Output in XML the received message.
                Log.info("Received Request Message:\n" + reqMsg.toXML());

                // Check if a response message should be returned.
                if (reqMsg.hasField("RESPOND-VIA-MSG"))
                {
                    // Create a Response Product message using the MessageFactory.
                    Message rspMsg = conn.getMessageFactory().createMessage(reqMsg.getStringValue("RESPOND-VIA-MSG"));
                    ...
                    if (reqMsg.hasField("PROD-TYPE"))
                    {
                        rspMsg.addField(reqMsg.getField("PROD-TYPE"));
                    }
                    if (reqMsg.hasField("PROD-SUBTYPE"))
                    {
                        rspMsg.addField(reqMsg.getField("PROD-SUBTYPE"));
                    }
                    ...

Basically, check if the incoming message has the RESPOND-VIA-MSG field, and if so, then use its value to create the appropriate response message.

Note, this is not perfect code, but it works. :-)