klein script CSS isn't working

Question

I have a very simple klein script that is just a reverse-proxy:

from klein import run, route, Klein
from twisted.web.proxy import ReverseProxyResource

@route('/')
def home(request, branch=True):
    return ReverseProxyResource('www.example.com', 80, ''.encode('utf-8'))

run("MY_IP", 80)

The only problem is the CSS doesn't work when the website is calling it using relative paths /css/example; I'm not sure how to fix this. I'm open to any suggestions.

I'm using Python-3.3.

Answer 1

This first block of code based on yours was my first pass, but it doesn't work.

It appeared to work for things like GET /a, but that's because /<path> doesn't include additional /'s. So anything that is deeper than one level won't get proxied.

Looking into @route, it uses werkzeug underneath which doesn't appear to allow arbitrary wildcards:

from klein import run
from klein import route
from twisted.web.proxy import ReverseProxyResource

@route('/', defaults={'path': ''})
@route('/<path>')
def home(request, path):
    print "request: " + str(request)
    print "path: " + path
    return ReverseProxyResource('localhost', 8001, path.encode('utf-8'))

run("localhost", 8000)

If you drop down into twisted, though, you can simply do this:

# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.

"""
This example demonstrates how to run a reverse proxy.

Run this example with:
    $ python reverse-proxy.py

Then visit http://localhost:8000/ in your web browser.
"""

from twisted.internet import reactor
from twisted.web import proxy, server

site = server.Site(proxy.ReverseProxyResource('www.example.com', 80, ''))
reactor.listenTCP(8000, site)
reactor.run()

If you want to catch, log, modify, etc, each request, you can subclass ReverseProxyResource and override render(). Note: you also have to override getChild() due to a bug:

from twisted.internet import reactor                                            
from twisted.web import proxy                                                   
from twisted.web import server                                                  
from twisted.python.compat import urlquote                                      

class MyReverseProxyResource(proxy.ReverseProxyResource):                       

    def __init__(self, host='www.example.com', port=80, path='', reactor=reactor):
        proxy.ReverseProxyResource.__init__(self, host, port, path, reactor)    

    def getChild(self, path, request):                                          
        # See https://twistedmatrix.com/trac/ticket/7806                        
        return MyReverseProxyResource(                                          
            self.host, self.port, self.path + b'/' + urlquote(path, safe=b"").encode('utf-8'),
            self.reactor)                                                       

    def render(self, request):                                                  
        print request                                                           
        return proxy.ReverseProxyResource.render(self, request)                 


p = MyReverseProxyResource()                                                    
site = server.Site(p)                                                           
reactor.listenTCP(8000, site)                                                   
reactor.run()

Output:

<Request at 0x14e9f38 method=GET uri=/css/all.css?20130620 clientproto=HTTP/1.1>
<Request at 0x15003b0 method=GET uri=/ clientproto=HTTP/1.1>

Answer 2

this will work

from klein import run, route, Klein
from twisted.web.proxy import ReverseProxyResource

@route('/',branch=True)
def home(request):
    return ReverseProxyResource('example.com', 80, ''.encode('utf-8'))

run("MY_IP", 80)

basically branch is argument to @route annotation not the home function