Synnefo

# Copyright 2012, 2013 GRNET S.A. All rights reserved.

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from django.http import HttpResponse, HttpResponseRedirect

from objpool.http import PooledHTTPConnection

from synnefo.lib import join_urls

from .utils import fix_header, forward_header

import urllib

import urlparse

# We use proxy to delegate requests to another domain. Sending host specific

# headers (Host, Cookie) may cause confusion to the server we proxy to.

#

# http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.10

# Connection and MUST NOT be communicated by proxies over further connections

EXCLUDE_HEADERS = ['Host', 'Cookie', 'Connection', 'X-Forwarded-Host']

def proxy(request, proxy_base=None, target_base=None, redirect=False):

    kwargs = {}

    if None in (proxy_base, target_base):

        m = "proxy() needs both proxy_base and target_base argument not None"

        raise AssertionError(m)

    # Get strings from lazy objects

    proxy_base = str(proxy_base)

    target_base = str(target_base)

    parsed = urlparse.urlparse(target_base)

    target_path = '/' + parsed.path.strip('/')

    proxy_base = proxy_base.strip('/')

    # prepare headers

    headers = dict(map(lambda (k, v): fix_header(k, v),

                   filter(lambda (k, v): forward_header(k),

                          request.META.iteritems())))

    # set X-Forwarded-For, if already set, pass it through, otherwise set it

    # to the current request remote address

    source_ip = request.META.get('REMOTE_ADDR', None)

    if source_ip and not 'X-Forwarded-For' in headers:

        headers['X-Forwarded-For'] = source_ip

    # request.META remains cleanup

    for k in headers.keys():

        if '_' in k:

            headers.pop(k)

    for k in EXCLUDE_HEADERS:

        headers.pop(k, None)

    kwargs['headers'] = headers

    kwargs['body'] = request.body

    path = request.path.lstrip('/')

    if not path.startswith(proxy_base):

        m = "request path '{0}' does not start with proxy_base '{1}'"

        m = m.format(path, proxy_base)

        raise AssertionError(m)

    path = path.replace(proxy_base, '', 1)

    # redirect to target instead of proxing

    if redirect:

        redirect_url = join_urls(target_base, path)

        qs = urllib.urlencode(request.GET)

        return HttpResponseRedirect('?'.join([redirect_url, qs]))

    path = join_urls(target_path, path)

    with PooledHTTPConnection(parsed.netloc, parsed.scheme) as conn:

        conn.request(

            request.method,

            '?'.join([path, urllib.urlencode(request.GET)]), **kwargs)

        response = conn.getresponse()

        # turn httplib.HttpResponse to django.http.Response

        length = response.getheader('content-length', None)

        data = response.read(length)

        status = int(response.status)

        django_http_response = HttpResponse(data, status=status)

        # do we need to exclude any headers here?

        for name, value in response.getheaders():

            django_http_response[name] = value

        return django_http_response