R. David Murray recently completed work funded by the PSF to update
Python's email package to work with Python 3.2. The result of the
project is a fully functioning version of the standard library package
for parsing and constructing email messages.
Project History
The version of the email package that was shipped with Python 3.0
and 3.1 had some bugs, not the least of which was the inability to
handle binary inputs. The parser was limited to files and messages in
ASCII. Due to this, under Python 3 the email module could only
create messages and never receive anything. This deficiency broke many
applications that depend on email. For example, the cgi
package uses the email package to process binary uploads.
After discussions held in the email-sig discussion group, a
complete rewrite of the API was suggested as the only option and
R. David Murray submitted a proposal to the PSF to fund the
development of Email 6. The proposal was initially accepted, and some
seed money (including matching funds) were provided. Since then,
additional funding has been provided by QNX.
At first, David spent some time working on the Policy framework, and
with some help from Antoine Pitrou, who fixed some issues in the
nntp module, David devised a way to integrated byte handling in
the email package without a complete rewrite of the original
code by using extensions to the API that allow it to accept
and generate bytes. The implementation used the "surrogateescape" mechanism, developed
by Martin von Löwis, allowing
minimum code modifications.
David also provided some modifications to smtplib, enabling it to
transmit messages with non-ASCII characters. He also worked with
Victor Stinner to give the cgi module the
ability to handle binary data. They then took on the task of updating
the mailbox module, and using the new features coded initially by
David, made mailbox fully functional for Python 3.2.
David mentions that there are still some bugs, specially in the
transition to the string/byte separation, but, also according to him,
these bugs were greatly reduced in version 3.2.
All this work gave Python 3.2 a fully functional email handling
package. The nntplib, smtplib, email, cgi and mailbox modules were also made
functional, something that benefits the whole Python community. The
grant provided by PSF paved the way to reach full functionality.
