Hi Tibi,
Nevow is probably the best. But there are other ways too. I've been
doing this for several years with a Tomcat servlet, and then there was
no Nevow. After converting to Pythonism, I switched to a Twisted server.
Haven't learned Nevow yet, despite good intentions..., but I think this
may be similar. It's essentially doing all of "What I want to do:"
below, only I'm not using it mainly for chat, but for distributing
HTML or Javascript, for viewing things together during a phone meeting.
- the browser's background HTTPRequest sits in a threaded applet
- someone switches on "collaboration" in his browser - the others see
his name being added to the "virtual meeting"
- one user drags a pointer (image) in his browser -> the pointer moves
in the other browsers
See also some A's to your Q's, below.
Harald
On 5/26/05, Tibi Dondera
Hello all,
I'm trying to develop a chat application through a browser, using twisted (if possible) What I want to do: - a user logs in the website - he goes to the "chat page" - he has the "classic" chat interface (sent messages, list of online users, "send a message" field). All of these are simple "divs" - when he sends a message, a post with the message is submitted to the server, and registered in a temporary database table (or in memory, is there some "temporary" memory that I can use in twisted for this purpose ?) - for refreshing the chat area, there is an open HTTPRequest in the background. Twisted will do the following: - accept the HTTPrequest connection - keep it alive (i.e. do not send the answer, but maybe send some empty chars to force the browser to keep the connection open) - when a new message (from the other users) is available, send it to the user and close the connection. - in the user's browser, when the connection is closed (either with a message, or after a certain timeout, that cannot be avoided anyway), a new one will be opened, until the user quits the chat.
Questions: - Is this a plausible solution ?
Yes, IMHO.
- Has this already been implemented (or at least partly) ? - Can this actually be done with twisted ?
Yes.
- Can I develop this on Windows ? (production will be on linux, but still, I prefer developing local, and currently on windows)
Hmm.. I develop "on Windows", but with a VMWare Linux server on the same laptop. Works great, but costs a bit. Should work with the server on Windows, too(?)
- Can you give me any pointers to some existing code, or where to start ? (maybe jabber for twisted ?)
Here's a few fragments from my server code - class Servlet(resource.Resource): ... # Send queued output to browser's background listener def render_GET(self, request): self.request = request session = request.getSession() ... anything = 0 while not session.outqueue.empty(): x = session.outqueue.get() request.transport.write(x) anything = 1 if anything: request.finish() return server.NOT_DONE_YET def render_POST(self, request): session = request.getSession() # Browser sends a dictionary as text msgDict = eval(request.args['message'][0]) request.finish() message = msgDict['message'] mSplit = message.split() ... # Do work here return server.NOT_DONE_YET
- How will a twisted http server coexist with my existing apache server on the 80 port ?
Not well, I guess. I use a different port for the Twisted server.
- Must I subscribe to the twisted-http mailing list instead and ask this question there ?
Twisted-web would be better, yes. I'm posting this one there too, with all due apologies...
Thanks for any help.
Tibi Dondera
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