[Python-bugs-list] [ python-Bugs-504152 ] rfc822 long header continuation broken

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Bugs item #504152, was opened at 2002-01-15 17:31
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Category: Python Library
Group: Python 2.1.1
Status: Open
Resolution: None
Priority: 5
Submitted By: Richard Jones (richard)
Assigned to: Nobody/Anonymous (nobody)
Summary: rfc822 long header continuation broken

Initial Comment:
I don't believe this is fixed in 2.1.2 or 2.2, but
haven't checked.

The code in rfc822.Message.readheaders incorrectly
unfolds long message headers. The relevant information
from rfc2822 is in section 2.2.3. In short:

"""
The process of moving from this folded multiple-line
representation of a header field to its single line
representation is called "unfolding". Unfolding is
accomplished by simply removing any CRLF that is
immediately followed by WSP.  Each header field should
be treated in its unfolded form for further syntactic
and semantic evaluation.
"""

This means that the code in readheaders:

            if headerseen and line[0] in ' \t':
                # It's a continuation line.
                list.append(line)
                x = (self.dict[headerseen] + "\n " +
line.strip())
                self.dict[headerseen] = x.strip()
                continue

should be:

            if headerseen and line[0] in ' \t':
                # It's a continuation line.
                list.append(line)
                x = self.dict[headerseen] + line
                self.dict[headerseen] = x.strip()
                continue

ie. no stripping of the leading whitespace and no
adding the newline.


----------------------------------------------------------------------

>Comment By: Richard Jones (richard)
Date: 2002-01-16 04:12

Message:
Logged In: YES 
user_id=6405

Yes, we had someone submit a bug report on the roundup 
users mailing list because someone had sent a message to 
the roundup mail gateway which was split. The client was 
extra-specially broken, since it split in the middle of a 
word (which is not to spec), but the more general case of 
folding on whitespace will cause roundup problems since I 
hadn't expected there to be any newlines in the header.

I can modify roundup to strip out the newline, but it'd be 
nice to have rfc822.Message not put it in there...



----------------------------------------------------------------------

Comment By: Guido van Rossum (gvanrossum)
Date: 2002-01-15 18:47

Message:
Logged In: YES 
user_id=6380

Richard, have you found a situation where it matters? I
thought that usually the next phase calls for normalizing
whitespace by squashing repeated spaces/tabs and removing
them from front and back.


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