Programming Python, 3rd Edition

The PyMailCGI Web Site

In Chapter 15, we built a program called PyMailGUI that implements a complete Python+Tkinter email client GUI (if you didn’t read that chapter, you may want to take a quick glance at it now). Here, we’re going to do something of the same, but on the Web: the system presented in this section, PyMailCGI, is a collection of CGI scripts that implement a simple web-based interface for sending and reading email in any browser. In effect, it is a simple webmail system—though not as powerful as what may be available from your Internet Service Provider (ISP), its scriptability gives you control over its operation and future evolution.

Our goal in studying this system is partly to learn a few more CGI tricks, partly to learn a bit about designing larger Python systems in general, and partly to underscore the trade-offs between systems implemented for the Web (the PyMailCGI server) and systems written to run locally (the PyMailGUI client). This chapter hints at some of these trade-offs along the way and returns to explore them in more depth after the presentation of this system.

Implementation Overview

At the top level, PyMailCGI allows users to view incoming email with the Post Office Protocol (POP) interface and to send new mail by Simple Mail Transfer Protocol (SMTP). Users also have the option of replying to, forwarding, or deleting an incoming email while viewing it. As implemented, anyone can send email from a PyMailCGI site, but to view your email, you generally ...