In my experience, you need to open 2 sockets: one to to listen for and accept incoming connections, and the other to connect to the other server.

If I'm understanding your 2 posts correctly, I would imagine a processing flow like:

  1. Remote Server listens on a port for incoming connections.
  2. When an incoming connection is detected, delegate a worker process/thread.
  3. Worker accepts the connection while the Remote Server resumes waiting for incoming connections.
  4. Worker receives the message and validates it.
  5. If validation fails, worker sends a negative response, closes the connection then becomes idle (or terminates itself).
  6. Otherwise, worker sends a positive response, closes the connection then processes the message.
  7. If no results message needs to be sent, worker becomes idle (or terminates itself).
  8. Otherwise, worker opens a socket, connects to your Local Server and sends the results message.
  9. Worker waits for positive/negative response. Once received, closes the connection.
  10. Worker performs any needed follow up based on the positive/negative response.
  11. Worker becomes idle (or terminates itself).

In the case where the Remote Server is initiating the transaction, a worker would proceed as above as though it were sending a results message. Any results sent back from the Local Server would be handled be handled the same as accepting requests as above.

I am sure there are modules/frameworks in CPAN that can handle the network part, especially if the communication between the Remote and Local servers is HTTP based.

In reply to Re: Bidirectional Client/Server - to fork or not to fork? by RonW
in thread Bidirectional Client/Server - to fork or not to fork? by ljamison

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