Re: [Quickfix-users] Fwd: exception thrown in python with twisted logging

[Oren M. <or...@qu...>]

This is apparently the default behavior of Swig when it receives a  
python exception from a callback.  It doesn't know what to do so it  
simply throws an DirectorMethodException and quits.  It is telling  
you that something went wrong, but does not provide any sort of  
reasonable feedback to help you figure out what it is.  The callback  
methods which handle exceptions already deal with this, however we  
did not think to handle the case where a callback method might throw  
an exception even when we were not expecting one.  I've checked in a  
fix for this.  Now when this happens, the actual python message will  
be printed out for you just as it would in a normal python  
application.  Running your example code in onCreate, I now get this:

Traceback (most recent call last):
   File "../examples/executor/python/executor.py", line 11, in onCreate
     print "SessionID = " + sessionID
TypeError: cannot concatenate 'str' and 'SessionID' objects

I'm guessing your other director exceptions are caused by similar  
python exceptions being thrown from the callbacks.  If you get the  
latest from svn, you will be able to see the real exceptions that are  
causing the application to break.

Also, is there a method in python that needs to be implemented on the  
SessionID object to make what you are doing legal?  Something that  
will automatically convert an object to a string during  
concatenation?  If so, we can implement it for all our serializable  
objects. Doing just print sessionID seems legal, so the print method  
seems to be converting to a string automatically.

--oren

On Sep 25, 2006, at 3:08 PM, Robert Parrott wrote:

> I'm using the python binding from quickfix 1.12.4, and seeing a
> possible bug in the python interface to the Application class. The
> platform is CentOS 4.4 (equiv to RHEL 4, update 4).
>
> class MyApplication(quickfix.Application):
>
>     def onCreate(self, sessionID):  print "Session ID = " + sessionID
>
> throws an exception when called: "terminate called after throwing an
> instance of 'Swig::DirectorMethodException' ".  However, calling
> sessionID.toString() here instead works.