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#!/usr/bin/env python
"""A web application that retrieves other websites for you.
To start serving the application on port 8088, type
python webproxy.py
To start the server on some other interface/port, use
python -m gevent.wsgi -p 8000 -i 0.0.0.0 webproxy.py
"""
from gevent import monkey; monkey.patch_all()
from gevent import wsgi
import sys
import re
import traceback
import urllib2
from urlparse import urlparse
from cgi import escape
from urllib import unquote
PORT = 8088
def application(env, start_response):
proxy_url = 'http://%s/' % env['HTTP_HOST']
method = env['REQUEST_METHOD']
path = env['PATH_INFO']
if env['QUERY_STRING']:
path += '?' + env['QUERY_STRING']
path = path.lstrip('/')
if (method, path) == ('GET', ''):
start_response('200 OK', [('Content-Type', 'text/html')])
return [FORM]
elif method == 'GET':
return proxy(path, start_response, proxy_url)
elif (method, path) == ('POST', ''):
key, value = env['wsgi.input'].read().strip().split('=')
assert key == 'url', repr(key)
start_response('302 Found', [('Location', join(proxy_url, unquote(value)))])
elif method == 'POST':
start_response('404 Not Found', [])
else:
start_response('501 Not Implemented', [])
return []
def proxy(path, start_response, proxy_url):
if '://' not in path:
path = 'http://' + path
try:
try:
response = urllib2.urlopen(path)
except urllib2.HTTPError, ex:
response = ex
print '%s: %s %s' % (path, response.code, response.msg)
headers = [(k, v) for (k, v) in response.headers.items() if k not in drop_headers]
scheme, netloc, path, params, query, fragment = urlparse(path)
host = (scheme or 'http') + '://' + netloc
except Exception, ex:
sys.stderr.write('error while reading %s:\n' % path)
traceback.print_exc()
tb = traceback.format_exc()
start_response('502 Bad Gateway', [('Content-Type', 'text/html')])
error_str = escape(str(ex) or ex.__class__.__name__ or 'Error')
return ['<h1>%s</h1><h2>%s</h2><pre>%s</pre>' % (error_str, escape(path), escape(tb))]
else:
start_response('%s %s' % (response.code, response.msg), headers)
data = response.read()
data = fix_links(data, proxy_url, host)
return [data]
def join(url1, *rest):
if not rest:
return url1
url2, rest = rest[0], rest[1:]
if url1.endswith('/'):
if url2.startswith('/'):
return join(url1 + url2[1:], *rest)
else:
return join(url1 + url2, *rest)
elif url2.startswith('/'):
return join(url1 + url2, *rest)
else:
return join(url1 + '/' + url2, *rest)
def fix_links(data, proxy_url, host_url):
"""
>>> fix_links("><img src=images/hp0.gif width=158", 'http://127.0.0.1:8088', 'www.google.com')
'><img src="http://127.0.0.1:8088/www.google.com/images/hp0.gif" width=158'
"""
def fix_link_cb(m):
url = m.group('url')
if '://' in url:
result = m.group('before') + '"' + join(proxy_url, url) + '"'
else:
result = m.group('before') + '"' + join(proxy_url, host_url, url) + '"'
#print 'replaced %r -> %r' % (m.group(0), result)
return result
data = _link_re_1.sub(fix_link_cb, data)
data = _link_re_2.sub(fix_link_cb, data)
return data
_link_re_1 = re.compile('''(?P<before>(href|src|action)\s*=\s*)(?P<quote>['"])(?P<url>[^#].*?)(?P=quote)''')
_link_re_2 = re.compile('''(?P<before>(href|src|action)\s*=\s*)(?P<url>[^'"#>][^ >]*)''')
drop_headers = ['transfer-encoding', 'set-cookie']
FORM = """<html><head>
<title>Web Proxy - gevent example</title></head><body>
<table width=60% height=100% align=center>
<tr height=30%><td align=center valign=bottom>Type in URL you want to visit and press Enter</td></tr>
<tr><td align=center valign=top>
<form action=/ method=post>
<input size=80 name=url value="http://www.gevent.org"/>
</form>
</td></tr>
</table></body></table>
"""
if __name__ == '__main__':
print 'Serving on %s...' % PORT
wsgi.WSGIServer(('', PORT), application).serve_forever()
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