How to iterate through maildir messages in python 3?

[Chris Angelico]

On Sat, Jun 26, 2021 at 12:28 AM Chris Green <cl at isbd.net> wrote:
>
> 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])
>
>     #    iterate over messages in the maildir and add to the mbox
>     for msg in maildir:
>         mbox.add(msg)
>

Maildir says that the factory has to take a binary file object. It
looks like email.message_from_file is expecting a text file object,
but there's a very similar function message_from_binary_file that
might be what you want.

Haven't tested it, but worth a try.

ChrisA