I have just started to look at the Twisted framework and would like to put it to use for a new project I am working on. Not being very familiar with the framework and fairly new to Python in general I would like to ask a design/architecture question. (I have written similar applications in C but would prefer to start this in the right direction and not write Python like C.)<br>
<br>The application has the following model:<br><br>Many clients connect to the Application and prefer to leave the connection open. They will send messages across this connection. They will expect to get a message back at some point later, they do not wait for a response (async). The clients are already coded (legacy) and just need to send their proprietary protocol to the new Application (written using Twisted).<br>
<br>The Twisted application will take the data from the clients and do some transformation on it then send the message on to another server (3rd party). This connection to "another" server must be a single connection, not one connection per client. This connection should also be persistent and not opened/closed for each client message sent. Ideally if the 3rd party server is down then I would also not accept client connections as the messages are time sensitive and should not be stored and forwarded. At some point the 3rd part will send a message back and the Application will route it back to the original source. Basically request/reply pattern.<br>
<br>I have been reading through the archives and the twisted docs and have also looked over the Hex-dump port-forwarding recipe but not found anything that explains how to use twisted for this model. Hex-dump is close but opens/closes the connection to the server on each client connection.<br>
<br>I am thinking that there will be two Factories [and two protocols: 1) for clients and 2) for 3rd party]. I am not sure how to best establish both the listening factory and the client to 3rd party factory. Once they are established what is the preferred way in Twisted to pass a message from one protocol to another?<br>
<br>Any pointers or sample code that you can offer is greatly appreciated. I would really like to cook this in Twisted and not go back to the C way.<br><br>Thanks,<br>-ab<br>