Python in a Nutshell, 2nd Edition

The SocketServer Module

The Python library supplies a framework module, SocketServer, to help you implement simple Internet servers. SocketServer supplies server classes TCPServer, for connection-oriented servers using TCP, and UDPServer, for datagram-oriented servers using UDP, with the same interface.

An instance s of either TCPServer or UDPServer supplies many attributes and methods, and you can subclass either class and override some methods to architect your own specialized server framework. However, I do not cover such advanced and rarely used possibilities in this book.

Classes TCPServer and UDPServer implement synchronous servers that can serve one request at a time. Classes ThreadingTCPServer and ThreadingUDPServer implement threaded servers, spawning a new thread per request. You are responsible for synchronizing the resulting threads as needed. Threading is covered in Threads in Python.

The BaseRequestHandler Class

For normal use of SocketServer, subclass the BaseRequestHandler class provided by SocketServer and override the handle method. Then instantiate a server class, passing the address pair on which to serve and your subclass of BaseRequestHandler. Finally, call serve_forever on the server instance.

An instance h of BaseRequestHandler supplies the following methods and attributes.

client_address	The h.client_address attribute is the pair (host,port) of the client, set by the base class at connection.
handle	h.handle( ) Your subclass overrides this method, and the server ...