How to iterate through maildir messages in python 3?

Fri Jun 25 04:19:49 EDT 2021

Greg Ewing <greg.ewing at canterbury.ac.nz> wrote:
> On 25/06/21 7:06 am, Chris Green wrote:
> > In python 2 one can do:-
> > 
> > for msg in maildir:
> > print msg # or whatever you want to do with the message
> > 
> > 
> > However in python 3 this produces "TypeError: string argument
> > expected, got 'bytes'".
> > 
> > How should one iterate over a maildir in python3?
>> You're already iterating over it just fine. Your problem is
> actually how to *print* a mail message.
>> The answer to this will depend on what your purpose is. If
> you just want a rough-and-ready idea of what the message
> contains, you could do this:
>> print(repr(msg))
>> However, that won't work very well if the message doesn't
> consist of mostly text in an ASCII-compatible encoding.
>> If you want something better, Python comes with some standard
> library code for dealing with mail messages. Check out the
> 'email' module.
>The error comes from the line "for msg in maildir:", not the print.
Here's the full program where I'm encountering the error (yes, I
should have posted this first time around) :-
 #!/usr/bin/python3
 import mailbox
 import sys
 import email
 # open the existing maildir and the target mbox file
 maildir = mailbox.Maildir(sys.argv [-2], email.message_from_file)
 mbox = mailbox.mbox(sys.argv[-1])
 # lock the mbox
 mbox.lock()
 # iterate over messages in the maildir and add to the mbox
 for msg in maildir:
 mbox.add(msg)
 # close and unlock
 mbox.close()
 maildir.close()
(... and it's not my coding style, just copied)
Here's the error trace:-
 chris$ ./md.py houseSitting fred
 Traceback (most recent call last):
 File "/home/chris/tmp/./md.py", line 18, in <module>
 for msg in maildir:
 File "/usr/lib/python3.9/mailbox.py", line 110, in itervalues
 value = self[key]
 File "/usr/lib/python3.9/mailbox.py", line 77, in __getitem__
 return self._factory(file)
 File "/usr/lib/python3.9/email/__init__.py", line 54, in message_from_file
 return Parser(*args, **kws).parse(fp)
 File "/usr/lib/python3.9/email/parser.py", line 56, in parse
 feedparser.feed(data)
 File "/usr/lib/python3.9/email/feedparser.py", line 175, in feed
 self._input.push(data)
 File "/usr/lib/python3.9/email/feedparser.py", line 103, in push
 self._partial.write(data)
 TypeError: string argument expected, got 'bytes'
 chris$ 
Line 18 is the "for msg in maildir:".
Presumably the program worked as posted under python 2, all I have
done is to change the shebang line to use python 3 (I no longer have
python 2 on my system, otherwise I'd have used it as this is only a
quick and dirty conversion script to be used once).
-- 
Chris Green
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