FollowTheRedirect.AppSpot.com source

gistfile1.py

#!/usr/bin/env python
#
# Copyright 2007 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
from google.appengine.ext import webapp
from google.appengine.ext.webapp import util
from google.appengine.api import urlfetch
import urlparse
import urllib
from google.appengine.api.urlfetch import DownloadError 

class MainHandler(webapp.RequestHandler):
    def get(self):
		url = urllib.unquote_plus(self.request.get("url"))
		callback = self.request.get("callback")
		content_type = "application/javascript"
		parsed = urlparse.urlparse(url)
		if callback=="" and url!="":
			self.response.headers["Content-Type"] = content_type
			self.response.out.write("Error. Callback parameter required")
		
		elif not hasattr(parsed,"scheme") or  not hasattr(parsed,"netloc") or parsed.scheme not in ("http, https") or parsed.netloc=='':
			self.response.headers["Content-Type"] = content_type
			self.response.out.write(callback+'({error:"The url parameter you provided is invalid."});')
		else:
		
			if url=="" and callback!="":
				self.response.headers["Content-Type"] = content_type
				self.response.out.write(callback+'({error:"must include a url parameter"});')
			elif callback=="" and url=="":
				self.response.headers["Content-Type"] = content_type
				self.response.out.write("Error. Both url and callback parameters required")
			else:
				try:
					result = urlfetch.fetch(url=url,method="HEAD",follow_redirects=False)
					self.response.headers["Content-Type"] = content_type
					try:
						self.response.out.write(callback+'({location:"'+result.headers[u'location']+'"});')
					except KeyError:
						self.response.out.write(callback+'({result:"No redirect header set for this url."});')
				except urlfetch.Error:
					self.response.headers["Content-Type"] = content_type
					self.response.out.write(callback+'({error:"The URL request was not successful."});')
					

def main():
    application = webapp.WSGIApplication([('/', MainHandler)],
                                         debug=False)
    util.run_wsgi_app(application)


if __name__ == '__main__':
    main()