Switch from urllib2 to requests breaks pip on certain setups

[nailor]

Switch introduced by commit ff2854a breaks pip on certain setups.

Sure, this can probably be blamed on those setups too, but it is somewhat bizarre when things all the sudden stop working.

Here's the case:
We run our internal pypi server (with pypi-server fronted by nginx). It serves tar.gz files, but with Content-Type application/x-tar it seems and with Content-Encoding set to 'gzip'.

Looks like when requests encounters this kind of request, it tries to gunzip it, resulting in deflating the actual zipped file.

My guess is that bottle does not handle this correctly in first place, however this breaks pip with pypiserver in version 1.5.

[nailor]

Looks like pypiserver has fix in place: pypiserver/pypiserver#42

[davidism]

👍 Ran into the same problem, we have the exact same setup. I know there's a fix in the works for pypiserver, but this seems like something pip might want to be more graceful about as well.

[dstufft]

Can you verify that this fixes the problem for you? #1435

[nailor]

Yup, works for me on with #1435 fix applied

[dstufft]

Perfect, thanks.

[dstufft]

Closed with #1435

[davidmarquis]

For the benefit of posterity (and easier searching for our fellow developers), this fixes the error "not a gzip file" that I experienced with the following stack trace:

Exception:
Traceback (most recent call last):
  File "venv/lib/python2.6/site-packages/pip/basecommand.py", line 122, in main
    status = self.run(options, args)
  File "venv/lib/python2.6/site-packages/pip/commands/install.py", line 270, in run
    requirement_set.prepare_files(finder, force_root_egg_info=self.bundle, bundle=self.bundle)
  File "venv/lib/python2.6/site-packages/pip/req.py", line 1164, in prepare_files
    self.unpack_url(url, location, self.is_download)
  File "venv/lib/python2.6/site-packages/pip/req.py", line 1311, in unpack_url
    retval = unpack_http_url(link, location, self.download_cache, self.download_dir, self.session)
  File "venv/lib/python2.6/site-packages/pip/download.py", line 565, in unpack_http_url
    unpack_file(temp_location, location, content_type, link)
  File "venv/lib/python2.6/site-packages/pip/util.py", line 624, in unpack_file
    untar_file(filename, location)
  File "venv/lib/python2.6/site-packages/pip/util.py", line 542, in untar_file
    tar = tarfile.open(filename, mode)
  File "/usr/lib64/python2.6/tarfile.py", line 1670, in open
    return func(name, filemode, fileobj, **kwargs)
  File "/usr/lib64/python2.6/tarfile.py", line 1721, in gzopen
    raise ReadError("not a gzip file")
ReadError: not a gzip file