Programming Python, Second Edition

Processing Internet Email

Some of the other most common higher-level Internet protocols have to do with reading and sending email messages: POP and IMAP for fetching email from servers,^[83] SMTP for sending new messages, and other formalisms such as rfc822 for specifying email message contents and format. You don’t normally need to know about such acronyms when using common email tools; but internally, programs like Microsoft Outlook talk to POP and SMTP servers to do your bidding.

Like FTP, email ultimately consists of formatted commands and byte streams shipped over sockets and ports (port 110 for POP; 25 for SMTP). But also like FTP, Python has standard modules to simplify all aspects of email processing. In this section, we explore the POP and SMTP interfaces for fetching and sending email at servers, and the rfc822 interfaces for parsing information out of email header lines; other email interfaces in Python are analogous and are documented in the Python library reference manual.

POP: Reading Email

I used to be an old-fashioned guy. I admit it: up until recently, I preferred to check my email by telneting to my ISP and using a simple command-line email interface. Of course, that’s not ideal for mail with attachments, pictures, and the like, but its portability is staggering -- because Telnet runs on almost any machine with a network link, I was able to check my mail quickly and easily from anywhere on the planet. Given that I make my living traveling around the world teaching ...