add examples/webproxy.py

d0536c3c · Denis Bilenko · ef94b6c6 · d0536c3c
Commit d0536c3c authored Sep 14, 2009 by Denis Bilenko
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examples/webproxy.py examples/webproxy.py +113 -0

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--- a/examples/webproxy.py
+++ b/examples/webproxy.py
+#!/usr/bin/python
+from gevent import monkey; monkey.patch_all(dns=True)
+from gevent import wsgi2
+import sys
+import re
+import traceback
+import urllib2
+from urlparse import urlparse
+from cgi import escape
+from urllib import unquote
+def application(env, start_response):
+    proxy_url = 'http://127.0.0.1:%(SERVER_PORT)s/' % env
+    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':
+        if '://' not in path:
+            path = 'http://' + path
+        try:
+            try:
+                r = urllib2.urlopen(path)
+            except urllib2.HTTPError, ex:
+                r = ex
+            print '%s: %s %s' % (path, r.code, r.msg)
+            headers = [(k, v) for (k, v) in r.headers.items() if k not in drop_headers]
+            parsed_path = urlparse(path)
+            host = (parsed_path.scheme or 'http') + '://' + parsed_path.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')])
+            return ['<h1>%s</h1><h2>%s</h2><pre>%s</pre>' % (escape(str(ex) or ex.__class__.__name__ or 'Error'), escape(path), escape(tb))]
+        #for key, value in r.headers:
+        else:
+            start_response('%s %s' % (r.code, r.msg), headers)
+            data = r.read()
+            data = fix_links(data, proxy_url, host)
+            return [data]
+    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 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.google.com"/>
+</form>
+</td></tr>
+</table></body></table>
+"""
+if __name__ == '__main__':
+    #import doctest
+    #doctest.testmod()
+    print 'Serving on 8088...'
+    wsgi2.WSGIServer(('', 8088), application).serve_forever()