[Twisted-Python] LineReceiver Protocol

Michael Mata michael.mata at gaigen.net
Sun Nov 21 16:50:31 EST 2004


Christopher Armstrong wrote:
> On Sat, 20 Nov 2004 23:12:18 -0800, Michael Mata
> <michael.mata at gaigen.net> wrote:
> 
>>Is there a way to extend the LineReceiver protocol to take action on a
>>continued, periodic basis?  Currently, the protocol only does work when 
>>a line is received.  However, there are times when the script should
>>take action without waiting to receive a line.
> 
> 
> It doesn't have anything to do with the protocol; what you want is
> reactor.callLater(seconds, functionToCall)
> 
> http://twistedmatrix.com/documents/current/howto/time has more information.
> 
> 
>>Another example might be a global message that needs to be sent to all
>>connections.  The message would have to be stored in  message queue and
>>sent only when lineReceived is called.  It would be nice if the message
>>could instead be sent imediately even if the connection was currently idle.
> 
> 
> For this you just want to keep track of all the protocols you want to
> send stuff to. doc/examples/chatserver.py shows how to do this.
> basically, in your lineReceived, you can do something like "for prot
> in self.factory.protocols: prot.sendMessage(line)".
> 
> 

The function task.LoopingCall(runEverySecond) from twisted.internet 
looks like a good fit for scheduling recurring maintenance.

If I follow chatserver.py, data globally available to all protocols 
should be stored in the reactor.  I'm guessing that if I want data 
associated to a specific instance of a protocol, I should store it in a 
variable under the protocol's __init__ function.

For example, I'd give a protocol a session id upon connection and add it 
to the client list in the reactor.  Now if I want to send a message to 
that client, I'd iterate throught the list in the reactor until I find 
the one with correct session id.




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