[New-bugs-announce] [issue4958] email/header.py ecre regular expression issue

Jan Malakhovski report at bugs.python.org
Fri Jan 16 00:33:09 CET 2009

New submission from Jan Malakhovski <jan.malachowski at gmail.com>:


I have dedicated mail server at home
and it holds about 1G of mail.
Most of mail is in non UTF-8 codepage, so today
I wrote little script that should recode
all letters to UTF. But I found that
email.header.decode_header parses some headers wrong.

For example, header
Content-Type: application/x-msword; name="2008
=?windows-1251?B?wu7v8O7x+w==?= 2 =?windows-1251?B?4+7kIDgwONUwMC5kb2M=?="
parsed as
[('application/x-msword; name="2008', None),
('\xc2\xee\xef\xf0\xee\xf1\xfb', 'windows-1251'), ('2
=?windows-1251?B?4+7kIDgwONUwMC5kb2M=?="', None)]
that is obviously wrong.

Now I'm playing with email/header.py file in
python 2.5 debian package
(but it's same in 2.6.1 version except that all <> changed to !=).

If it's patched with
==================BEGIN CUT==================
--- oldheader.py	2009-01-16 01:47:32.553130030 +0300
+++ header.py	2009-01-16 01:47:16.783119846 +0300
@@ -39,7 +39,6 @@
   \?                    # literal ?
   (?P<encoded>.*?)      # non-greedy up to the next ?= is the encoded
   \?=                   # literal ?=
-  (?=[ \t]|$)           # whitespace or the end of the string
 # Field name regexp, including trailing colon, but not separating
==================END CUT==================
it works fine.

So I wonder if this
  (?=[ \t]|$)           # whitespace or the end of the string
really needed, after all if there is only
whitespaces after encoded word, its just
appended to the list by

parts = ecre.split(line)

Also, there is related mail list thread:

components: Library (Lib)
messages: 79927
nosy: oxij
severity: normal
status: open
title: email/header.py ecre regular expression issue
type: behavior
versions: Python 2.5, Python 2.6

Python tracker <report at bugs.python.org>

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