Programming Python, Second Edition

Rolling Your Own Servers in Python

Most of the Internet modules we looked at in the last few chapters deal with client-side interfaces such as FTP and POP, or special server-side protocols such as CGI that hide the underlying server itself. If you want to build servers in Python by hand, you can do so either manually or by using higher-level tools.

Coding Solutions

We saw the sort of code needed to build servers manually in Chapter 10. Python programs typically implement servers either by using raw socket calls with threads, forks, or selects to handle clients in parallel, or by using the SocketServer module.

In either case, to serve requests made in terms of higher-level protocols such as FTP, NNTP, and HTTP, you must listen on the protocol’s port and add appropriate code to handle the protocol’s message conventions. If you go this route, the client-side protocol modules in Python’s standard library can help you understand the message conventions used. You may also be able to uncover protocol server examples in the Demos and Tools directories of the Python source distribution and on the Net at large (search http://www.python.org). See prior chapters for more details on writing socket-based servers.

As a higher-level interface, Python also comes with precoded HTTP web protocol server implementations, in the form of three standard modules. BaseHTTPServer implements the server itself; this class is derived from the standard SocketServer.TCPServer class. SimpleHTTPServer