ETags Proxy for GMod http fetching and caching :x (does not work since no headers get transmitted, need to move header responses to body)

etagsproxy.py

import webapp2
from google.appengine.api import memcache
from google.appengine.api import urlfetch
from google.appengine.ext import db
import hashlib



reason_texts = {
414:"fu",
504:"slow",
413:"wtf",
502:"download",
500:"ew"
}


class MainHandler(webapp2.RequestHandler):
	def __cacheget(self,url):
		self.cachekey = hashlib.md5(url).hexdigest()
		data = memcache.get(self.cachekey)
		if data is not None:
			if isinstance(data, (int, long)):
				self._process_response( status_code=data,cached=True)
				return True
			else:
				l = len(data)
				ETag = data[0]
				furl = data[1]
				self._process_response( ETag=ETag,furl=furl,status_code=200,cached=True)
				return True
		return False

	def _process_response(self,ETag=None,furl=None,cached=False,status_code=None):
		if status_code<0:
			timeout = status_code == -504
			self.response.set_status( -status_code, reason_texts.get(-status_code,None) )
			self.response.write("")
			memcache.add(self.cachekey, status_code, timeout and 30 or 60)
			return
			
		if status_code != 200:
			data = status_code
			if status_code == 404:
				self.response.set_status(404,"fok")
			else:
				self.response.headers.add_header("x-status",str(status_code))
		else:
			if cached:
				self.response.headers.add_header("x-cached","1")
			
			if ETag:
				self.response.headers.add_header("x-etag",ETag)
			
			if furl:
				self.response.headers.add_header("x-url",furl)
			data = [ETag,furl]
		
		self.response.write("")
		memcache.add(self.cachekey, data, 60)
	
	def get(self):
		url = self.request.headers.get("url",False)
		
		if not url or url=="":
			return self.response.set_status(400,"fok off")

		if len(url)>1024:
			return self.response.set_status(414,"loongcat")

		if self.__cacheget(url):
			return
			
		# no filesize limit :(
		try:
			result = urlfetch.fetch(url=url,
				method=urlfetch.HEAD,
				allow_truncated=True,
				follow_redirects=True,
				deadline=7,
				validate_certificate=False #,	headers={'Content-Type': 'application/x-www-form-urlencoded'}
				)
		except urlfetch.InvalidURLError as e:
			return self._process_response(status_code=-414)
		except urlfetch.DeadlineExceededError as e:       
			return self._process_response(status_code=-504)
		except urlfetch.ResponseTooLargeError as e:       
			return self._process_response(status_code=-413)
		except urlfetch.DownloadError as e:               
			return self._process_response(status_code=-502)
		except urlfetch.SSLCertificateError as e:         
			return self._process_response(status_code=-500)
		
		status_code = result.status_code
		furl = result.final_url
		ETag = result.headers.get("ETag",False)
		
		return self._process_response(  status_code=status_code,
										ETag=ETag,
										furl=furl)
		
app = webapp2.WSGIApplication([('/', MainHandler)], debug=False)