from urlparse import urlparse, urlsplit
from cgi import parse_qs
import cStringIO as StringIO
from twisted.internet import defer
from twisted.web import server, resource, client
def encodeFormData(arg, value):
"""Encode data as a multipart/form-data
"""
BOUNDARY = '----------BOUNDARY'
l = []
l.append('--' + BOUNDARY)
l.append('Content-Disposition: form-data; name="%s"' % arg)
l.append('')
l.append(value)
l.append('--' + BOUNDARY + '--')
l.append('')
body = '\r\n'.join(l)
contentType = 'multipart/form-data; boundary=%s' % BOUNDARY
return body, contentType
class FakeTransport(object):
def __init__(self):
self.io = StringIO.StringIO()
def writeSequence(self, sequence):
self.io.writelines(sequence)
def write(self, data):
self.io.write(data)
def getData(self):
return self.io.getvalue()
class MarkupValidator(resource.Resource):
"""A simple gateway to a validator service for Twisted Web.
"""
# Please, install a validator on your server!
uri = 'http://validator.w3.org/check'
arg = 'fragment'
def __init__(self, site):
"""site is the site object of your twisted.web server
"""
self.site = site
def render_GET(self, request):
def finish(data):
# Write the data back to our client
request.clientproto = clientproto
transport.write(data)
transport.loseConnection()
# Get the referer and parse it
referer = request.getHeader('referer')
scheme, netloc, path, parameters, query, fragment = urlparse(referer)
args = parse_qs(query)
transport = request.transport
clientproto = request.clientproto
# Modify the original request
request.uri = referer
request.path = path
request.args = args
request.clientproto = 'HTTP/1.0' # we don't want chunk encoding
request.transport = FakeTransport()
# Reload the modified request on the server, without using HTTP
deferred = request.notifyFinish()
request.process()
# XXX TODO handle errors
deferred.addCallback(lambda _: request.transport.getData()
).addCallback(self.validate, request
).addCallback(finish)
return server.NOT_DONE_YET
def validate(self, data, request):
# We need only the body
data = data[data.find('\r\n\r\n') + 4:]
# Build the request for the validator service, using the
# original request as the base
headers = request.received_headers
data, contentType = encodeFormData(self.arg, data)
headers['content-type'] = contentType
headers.pop('cookie', None)
headers.pop('referer', None)
headers.pop('host', None)
return client.getPage(
self.uri, method='POST', headers=headers, postdata=data
)
if __name__ == '__main__':
"""A simple usage example.
"""
from twisted.web import server
from twisted.internet import reactor
class Simple(resource.Resource):
def render_GET(self, request):
return """<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
lang="en" xml:lang="en">
<head>
<title>twvalidator example</title>
</head>
<body>
<h1>twvalidator example</h1>
<p><a href="validate">validate</a></p>
</body>
</html>"""
def getChild(self, name, request):
if name == '':
return self
return resource.Resource.getChild(
self, name, request)
root = Simple()
site = server.Site(root)
root.putChild('validate', MarkupValidator(site))
reactor.listenTCP(8080, site)
reactor.run()
