One-click pip setup for windows

distribute_and_pip.py

"""
This gist is a one-click pip setup for windows:

 1. installs distribute if needed
 2. installs pip
 3. (On windows) sets the path environment variable so "pip" is always runnable from cmd.

Tested on Windows 7 with python2.7
"""

import subprocess
try:
    from urllib import urlopen
except ImportError:
    # py3k
    from urllib.request import urlopen
import os
import tarfile
import platform
import sys

distribute_url = 'http://pypi.python.org/packages/source/d/distribute/distribute-0.6.32.tar.gz'
get_pip_url = 'https://raw.github.com/pypa/pip/master/contrib/get-pip.py'

python = sys.executable

def download(url):
    print('downloading %s' % url)
    fname = os.path.basename(url)
    with open(fname, 'wb') as f:
        data = urlopen(url).read()
        f.write(data)
        
    return fname

def run(line):
    return subprocess.check_output(line, shell=True)

def add_path_env_windows(new_path):
    # checks both user and system path
    path_str = os.environ['path']
    if new_path.lower() in path_str.lower():
        return
    else:
        print('Adding pip to user path')
        # Add to user path
        # The system path "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Environment"
        # may not be writable using setx /m because of permissions.
        output = run('reg query "HKEY_CURRENT_USER\Environment" /v path')
        output = output.decode(sys.stdout.encoding)
        previous_path = output.split('    ')[3].strip(';\r\n')
        total_path_str = previous_path + ';' + new_path
        execline = 'setx path "%s"' % total_path_str
        if hasattr(execline, 'decode'):
            # python 2
            run(execline.encode(sys.getfilesystemencoding()))
        else:
            # python 3
            run(execline)

def main():
    try:
        import setuptools
    except ImportError:
        # install distribute
        fname = download(distribute_url)
        
        with tarfile.open(fname) as tar:
            dirname = tar.getnames()[0]
            tar.extractall()
        run(python + ' %s/setup.py install' % dirname)
    
    try:
        import pip
    except ImportError:
        pipf = download(get_pip_url)
        run(python + ' %s' % pipf)
    
    if platform.system() == 'Windows':
        # add to environment path e.g. "C:\python27\Scripts" so you can run "pip"
        # in the command line
        add_path_env_windows(os.path.join(sys.exec_prefix, 'Scripts'))

main()