How to parse an email in Python without closing the file?

Question

I still need to use the file after it is parsed as en email but the email parser is closing it.

What can I do?

thanks

(venv3.4)ubuntu@core01:~/tmp$ cat tmp.eml
From: Example Person <example.person@example.org>
To: another.person@example.org
Subject: test2
Date: Sun, 2 Mar 2014 15:42:27 +1100

Hello

(venv3.4)ubuntu@core01:~/tmp$ cat tmp.py

from email.parser import BytesParser, BytesHeaderParser
from email import policy

f = open('tmp.eml', 'rb')

def parsefromfile(f, headersonly=None):
    f.seek(0)
    if headersonly:
        msg = BytesHeaderParser(policy=policy.default).parse(f)
    else:
        msg = BytesParser(policy=policy.default).parse(f)
    print(msg)
    print(msg.get('date', None))
    f.seek(0)
    print(f.read())

parsefromfile(f)


(venv3.4)ubuntu@core01:~/tmp$ python tmp.py

From: Example Person <example.person@example.org>
To: another.person@example.org
Subject: test2
Date: Sun, 2 Mar 2014 15:42:27 +1100

Hello


Sun, 02 Mar 2014 15:42:27 +1100
Traceback (most recent call last):
  File "tmp.py", line 17, in <module>
    parsefromfile(f)
  File "tmp.py", line 14, in parsefromfile
    f.seek(0)
ValueError: seek of closed file

Answer 1

Use the parsebytes function instead. Get the string content of the file using .read() and pass that in, then continue operating on your file object.

Answer 2

So, this was actually a bug in python - http://bugs.python.org/issue21476. The fix is set to go live, I think, on python3.5 and next minor version of python 3.4 i.e. 3.4.2. The file descriptor should not get closed, and OPs code should be valid for those versions.