[Twisted-Python] Sending disconnect messages to clients
Hi all, I'm sure I asked this question before, but I can't find any answers on google, and I've changed my work flow a bit now, so thought it was worth re-asking. So on my server's protocol, I have a send method. This allows me to pass arguments which get sent off to the client in the right format. The send method looks something like this: def send(self, command, **kwargs): """Cause the client to issue getattr(connection, command)(**kwargs). If disconnect evaluates to True, disconnect the client after the message is sent.""" disconnect = kwargs.get('disconnect', False) try: del kwargs['disconnect'] except KeyError: pass # Argument not found. d = defer.Deferred() d.addCallback(self.prepare_command) Convert the command and kwargs to json. d.addCallback(self.deferred_write) # Write the json to the transport. if disconnect: d.addCallback(self.deferred_disconnect) # Issue self.transport.loseConnection(). reactor.callFromThread(d.callback, [command, kwargs]) # Call the deferred's callback chain. return d # Return the deferred. If I try something like: protocol.send('alert', message = '*** Disconnected. ***', disconnect = True) the client gets disconnected, but never sees the "*** Disconnected. ***" message. I guess I could do a reactor.callLater and just wait for the transport to get the message, but that seems sloppy, and I can't help thinking there must be something I'm missing. Any ideas welcome! Cheers all,
Hi Chris, On March 22, 2016 at 2:42:14 PM, Chris Norman (chris.norman2@googlemail.com) wrote: Hi all, I'm sure I asked this question before, but I can't find any answers on google, and I've changed my work flow a bit now, so thought it was worth re-asking. So on my server's protocol, I have a send method. This allows me to pass arguments which get sent off to the client in the right format. The send method looks something like this: def send(self, command, **kwargs): """Cause the client to issue getattr(connection, command)(**kwargs). If disconnect evaluates to True, disconnect the client after the message is sent.""" disconnect = kwargs.get('disconnect', False) try: del kwargs['disconnect'] except KeyError: pass # Argument not found. d = defer.Deferred() d.addCallback(self.prepare_command) Convert the command and kwargs to json. d.addCallback(self.deferred_write) # Write the json to the transport. if disconnect: d.addCallback(self.deferred_disconnect) # Issue self.transport.loseConnection(). You are disconnecting right here, without waiting for your Deferred to fire. It might make better sense to add the call the self.transport.loseConnection() to your Deferred’s callback chain. Hope this helps, Daniel -- L. Daniel Burr ldanielburr@me.com (312) 656-8387
Hi Daniel, On 22/03/2016 19:49, L. Daniel Burr wrote:
Hi Chris,
On March 22, 2016 at 2:42:14 PM, Chris Norman (chris.norman2@googlemail.com <mailto:chris.norman2@googlemail.com>) wrote:
Hi all, I'm sure I asked this question before, but I can't find any answers on google, and I've changed my work flow a bit now, so thought it was worth re-asking.
So on my server's protocol, I have a send method. This allows me to pass arguments which get sent off to the client in the right format. The send method looks something like this:
def send(self, command, **kwargs): """Cause the client to issue getattr(connection, command)(**kwargs). If disconnect evaluates to True, disconnect the client after the message is sent.""" disconnect = kwargs.get('disconnect', False) try: del kwargs['disconnect'] except KeyError: pass # Argument not found. d = defer.Deferred() d.addCallback(self.prepare_command) Convert the command and kwargs to json. d.addCallback(self.deferred_write) # Write the json to the transport. if disconnect: d.addCallback(self.deferred_disconnect) # Issue self.transport.loseConnection().
You are disconnecting right here, without waiting for your Deferred to fire. It might make better sense to add the call the self.transport.loseConnection() to your Deferred’s callback chain.
Hope this helps,
Actually it's been added to the callback. I think my mail client wrapped the lines, but issue self.transport.LoseConnection() is the comment, so self.deferred_disconnect is added to the callback chain. Sorry for the confusion. Anything else which can cause this? Cheers,
Daniel -- L. Daniel Burr ldanielburr@me.com <mailto:ldanielburr@me.com> (312) 656-8387
_______________________________________________ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Hi Chris, On March 22, 2016 at 3:09:08 PM, Chris Norman (chris.norman2@googlemail.com) wrote: Hi Daniel, [SNIP] Actually it's been added to the callback. I think my mail client wrapped the lines, but issue self.transport.LoseConnection() is the comment, so self.deferred_disconnect is added to the callback chain. Sorry for the confusion. Anything else which can cause this? Without seeing the rest of your code, I can’t suggest anything concrete. You say the client never “sees” the message, but your call to loseConnection() still occurs, so you’re not encountering an exception during the callback chain. Can you come up with an minimal example the demonstrates the problem? Daniel — L. Daniel Burr ldanielburr@me.com (312) 656-8387
OK... ignore me. I made your test program and it worked fine. So I tried connecting to my server with telnet and saw the expected message... So I checked the error function which should have been called on the client with the particular message to see it was as good as pass... Sorry for all the messages, everything works fine, panic over! Thank you for your help with this! On 22/03/2016 20:37, L. Daniel Burr wrote:
Hi Chris,
On March 22, 2016 at 3:09:08 PM, Chris Norman (chris.norman2@googlemail.com <mailto:chris.norman2@googlemail.com>) wrote:
Hi Daniel,
[SNIP]
Actually it's been added to the callback. I think my mail client wrapped the lines, but issue self.transport.LoseConnection() is the comment, so self.deferred_disconnect is added to the callback chain.
Sorry for the confusion.
Anything else which can cause this?
Without seeing the rest of your code, I can’t suggest anything concrete. You say the client never “sees” the message, but your call to loseConnection() still occurs, so you’re not encountering an exception during the callback chain. Can you come up with an minimal example the demonstrates the problem?
Daniel — L. Daniel Burr ldanielburr@me.com <mailto:ldanielburr@me.com> (312) 656-8387
_______________________________________________ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
participants (2)
-
Chris Norman -
L. Daniel Burr