{{{
#!python
# File: README

"""

 A simple middleware component that lets you use a single Django
 instance to server multiple distinct hosts.

 IMPORTANT!! Make sure this is the FIRST entry in your MIDDLEWARE_CLASSES

 Revision log:

 v1.2 - 10th January 2012 (Cal Leeming - cal.leeming@simplicitymedialtd.co.uk)
  * Added 'LoadingTime' response header (tells us how long the request took to process)
  * Added 'MultiHost' response header (tells us if multihost was used or not)
  * Added 'HOST_MIDDLEWARE_URLCONF_MAP' example
  * Cleaned up code slightly

"""

}}}

{{{
#!python
# File: settings.py

HOST_MIDDLEWARE_URLCONF_MAP = {
    # Control Panel
    "www.example.com": "webapp.sites.example.urls",
}

}}}

{{{
#!python
# File: multihost.py

from django.conf import settings
from django.utils.cache import patch_vary_headers

class MultiHostMiddleware:

    def process_request(self, request):
        try:
            request.META["LoadingStart"] = time.time()
            host = request.META["HTTP_HOST"]
            #if host[-3:] == ":80":
            #    host = host[:-3] # ignore default port number, if present

            # best way to do this.
            host = request.META["HTTP_HOST"]
            host_port = host.split(':')

            if len(host_port)==2:                    
                host = host_port[0] 

            if settings.HOST_MIDDLEWARE_URLCONF_MAP.has_key(host):
                request.urlconf = settings.HOST_MIDDLEWARE_URLCONF_MAP[host]
                request.META["MultiHost"] = str(request.urlconf)
            else:
                request.META["MultiHost"] = str(settings.ROOT_URLCONF)

        except KeyError:
            pass # use default urlconf (settings.ROOT_URLCONF)

    def process_response(self, request, response):
        if request.META.has_key('MultiHost'):
            response['MultiHost'] = request.META.get("MultiHost")

        if request.META.has_key('LoadingStart'):
            _loading_time = time.time() - int(request.META["LoadingStart"])
            response['LoadingTime'] = "%.2fs" % ( _loading_time, )

        if getattr(request, "urlconf", None):
            patch_vary_headers(response, ('Host',))
        return response
}}}