[Twisted-Python] Help creating a client for a custom protocol

[Andrew Bennetts]

On Tue, Jun 24, 2003 at 06:13:29PM -0500, Don Hiatt wrote:
> Greetings,
> 
> Sorry about the newbie question, but... :)
> 
> I have a custom server running a byte-oriented protocol
> (sockets, written in C) and would like to use twisted to implement
> the client. I see from looking at the "simpleclient" how
> you can use an existing protocol (e.g. Echo) but I am not
> sure how to create a client using my own byte-oriented (e.g.
> "raw") protocol. If anyone could give me a little advice I
> would certainly appreciate it. :) Also, is ClientFactory appropriate
> for this sort of application?

Well, the 'data' parameter of an Protocol's dataReceived method is just a
string, i.e. bytes directly from the network.  I've used Twisted in the past
for working with byte stream protocols -- it works very nicely.

A key part is the 'struct' module in Python's standard library, which can
convert bytes to numbers, and so forth.  Take a look at the source to
twisted.protocols.basic.Int32Receiver, which receives strings prefixed by a
32-bit length.  There's really nothing to it :)

Regarding ClientFactory -- yes, whenever you are using clients, you probably
want some sort of ClientFactory (quite possibly a ReconnectingClientFactory,
depending on the application).  See
    http://twistedmatrix.com/documents/howto/clients
for an overview of using ClientFactory.

-Andrew.