[Tutor] GzipFile has no attribute '__exit__'

[Sander Sweers]

2009/11/16 Dave Angel <davea at ieee.org>:
> Alternatively, you could subclass it, and write your own.  At a minimum, the
> __exit__() method should close() the stream.

This triggered my to dig into this a bit. This is not fixed untill
python 3.1 but seems easilly added to the ZipFile class. My attempt to
backport this from python 3.1's gzip.py below seems to work.

Greets
Sander

import gzip

class myGzipFile(gzip.GzipFile):
    def __enter__(self):
        if self.fileobj is None:
            raise ValueError("I/O operation on closed GzipFile object")
        return self

    def __exit__(self, *args):
        self.close()

zfilepath = r'C:\test.gz'
s = 'This is a test'

with myGzipFile(zfilepath,'w') as output:
    output.write(s)