Unable to answer call using PJSUA2 - always sends 500 (Python)

Question

I am using Python 3.8 with pjsua2 using swig (built using the files given in the pjsip source code)

I can make calls fine.

However, when I attempt to answer a call (using 180 or 200), like so:

    def onIncomingCall(self, prm):
        c = Call(self, call_id=prm.callId)
        call_prm = pj.CallOpParam()
        call_prm.statusCode = 180
        c.answer(call_prm)

I get the following in the console log (set to 5):

10:27:04.033           pjsua_call.c  ...Answering call 0: code=180
10:27:04.033           pjsua_call.c  ....Pending answering call 0 upon completion of media transport
10:27:04.033           pjsua_call.c  ...Call 0 hanging up: code=0..
10:27:04.033           pjsua_call.c  ....Pending call 0 hangup upon completion of media transport
10:27:04.033           pjsua_call.c  ...Call 0 hanging up: code=500..
10:27:04.033           pjsua_call.c  ....Pending call 0 hangup upon completion of media transport

The logs just show immediate hangup with no clue what the issue is.

Can anyone help with this issue? I did the same logic of code in Java with the library and that seemed to work fine, but I really need to use Python.

Many thanks

Answer 1

This turned out to be the Python garbage collection prematurely removing the call object.

Which is documented on the PJSUA2 docs here

To fix the issue I created a class to store pjsip call objects so it was still referenced, and then removed them when needed.