RE: [pygame] Networking?

[Chris Ashurst <CAshurst@xxxxxxxx>]

I hope you mean that the sockets library is not the place to start, simply
because it's not immediately easy (unlike Twisted) to get right into? I
believe every programmer who wants to use a higher-level library should at
least have a stab at the low-level stuff, just to give a better idea of
what's going on behind the automagical scenese of things like Twisted
 
Rather than haul in Twisted, a little research on the Python select module
could be the very thing people are looking for - all without having any
extra dependencies/includes other than the core Python library and Pygame.
 
http://www.amk.ca/python/howto/sockets/
<http://www.amk.ca/python/howto/sockets/ - > - the Non-blocking Sockets
section is particularly enlightening
 
If potential socketeers out there are worried about things like byte-order
and so on, remember that the IRC protocol is 100% ASCII-based, and whilst it
may have its problems here and there, for the most part it's one of the
oldest, reliable protocols available (and great to learn from).
 
---
 
The python sockets library is probably *not* the place to start.  It is very
primitive,
and most references you will read will recommend using a  higher level
library such as
asyncore or (higher yet) asynchat.  Unfortunately, these higher level
libraries share the 
same weakness as Twisted, in that that they expect to own the main loop.
 
---
 

-----Original Message-----
From: owner-pygame-users@xxxxxxxx [mailto:owner-pygame-users@xxxxxxxx]On
Behalf Of David
Sent: Tuesday, November 20, 2007 09:44
To: pygame-users@xxxxxxxx
Subject: Re: [pygame] Networking?


 
The python sockets library is probably *not* the place to start.  It is very
primitive,
and most references you will read will recommend using a  higher level
library such as
asyncore or (higher yet) asynchat.  Unfortunately, these higher level
libraries share the 
same weakness as Twisted, in that that they expect to own the main loop.
 
I have identified five general approaches to integrating networking with a 
pygame application.  I have not fully implemented a game with any of them,
.. but soon.
 
1)  Use Twisted with reactor.iterate .  This is the easiest approach, and
the one that 
Mr Wittber's library uses.  Use of reactor.iterate is unfortunately
deprecated by the Twisted 
developers, and will, presumably, be removed from Twisted in some future
release.
 
2) Use the Twisted reactor *as* your main loop, and implement all game logic
as call-backs from 
there.  This is the approach that the Twisted people will recommend.   This
approach
is quite burdensome, in that structuring your game into a series of
callbacks can be difficult.  Using
generators as coroutines provides some relief, in that you can pass the
generators 'next' method 
as a callback to Twisted, and maintain game state within the generator.
Using subroutines or 
nested generators involve their own awkwardnesses.
 
3) Run the Twisted reactor in its own thread, and use ThreadedSelectReactor
to move 
data to the pygame event queue.  Bob Ippolito has blogged on how to use this
with Pygame (GIYF).
Unfortunately, ThreadedSelectReactor is unmaintained and deprecated.
 
4)  Run the Twisted reactor in its own thread, and use thread-safe queues to
move data 
to and from the main thread.  Alternatively, if you wish to use the
perspective-broker 
features or use Twisted code beyond mere message passing, there are tools in
Twisted for
safely invoking methods in other threads.  Hmm. maybe these were deprecated
with the TSR?
 
5)  Run the Twisted reactor in its own process, and use pipes or sockets to
pass data between
it and the main loop/process.  This has the merit of using the OS's CPU
allocation management 
rather than that of Python's thread manager.
 
Most of these approaches could use asyncore/asynchat as an alternative to
Twisted.
 
My own efforts lately have been along approaches 2 and 5.   My engine
'Spyre' will run under 
Twisted's reactor now, but the getting the whole multi-engine game logic
sequence working in 
the 'inside-out' callback style is an imposing prospect.  
 
Philip Hassey has recently released a networked pygame-based game.  Has he
mentioned what 
networking approach he used?
 
David
 
On 11/19/07, Jason Ward < nyad55@xxxxxxxxx <mailto:nyad55@xxxxxxxxx> >
wrote: 

I want to make my game playable over the network and if possible the
internet.
For the network it must support more than 2 computers and be realtime
Would the sockets library in python solve all my needs?




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