Programming Python, 3rd Edition

The mailtools Utility Package

The email package used by the pymail example of the prior section is a collection of powerful tools—in fact, perhaps too powerful to remember completely. At the minimum, some reusable boilerplate code for common use cases can help insulate you from some of its details. To simplify email interfacing for more complex mail clients, and to further demonstrate the use of standard library email tools, I developed the custom utility modules listed in this section—a package called mailtools.

mailtools is a Python modules package: a directory of code, with one module per tool class, and an initialization module run when the directory is first imported. This package’s modules are essentially just a wrapper layer above the standard library’s email package, as well as its poplib and smtplib modules. They make some assumptions about the way email is to be used, but they are reasonable and allow us to forget some of the underlying complexity of the standard library tools employed.

In a nutshell, the mailtools package provides three classes—to fetch, send, and parse email messages. These classes can be used as superclasses to mix in their methods to an application-specific class or to create standalone or embedded objects that export their methods. We’ll see these classes deployed both ways in this text.

One design note worth mentioning up front: none of the code in this package knows anything about the user interface it will be used in (console, GUI, web, or other), ...