When doing web development, you'll occasionally run into a situation where you are developing a new user interface or otherwise redesigning a website, but either cannot or don't want to tear out the existing pieces you are replacing. Maybe the tyrannical IT department has to approve all reboots for the development server, or your new project is a quick prototype down a different line of thought and you don't want to devote time to replacing the current system before the prototype proves its value.
As it often does, Django steps in as a handy tool in this situation. With some minimal customization you can use the Django development server to serve certain urls patterns and transparently proxy the remainder to another server.
For development, the Django development server is a real boon. It isn't quick, but it's quick enough, and its automatic reboots on code changes really speeds up development.
In particular, this approach allows you to use XMLHttpRequest-based
Ajax functionality cross-domain without your browser slapping your hand and saying no. This works because you're requesting the URL locally,
the proxy is fetching it from the remote host, and finally it is being returned to the requester it as if it all occurred locally.
This also means that
when you do integrate your new UI/feature into the existing application, you won't need to change any of the urls.
Don't need admin access (or ability/know-how to build) the
main server. You don't have to wait for the server to reboot,
caches to clear, or settings to reset.
Using Django as a proxy is quite simple. First you'll need to install Django and Httplib2:
curl http://www.djangoproject.com/download/1.0/tarball/ > Django-1.0.tar.gz
tar xzvf Django-1.0.tar.gz
sudo python setup.py install
sudo easy_install httplib2
Next put together a standard settings.py file. If you're just developing a new appearance or interface using static files, then your settings might look as simple as this:
importosROOT_PATH=os.path.dirname(__file__)# Change this to the domain where you# want requests to be proxied to.PROXY_DOMAIN="127.0.0.1:5678"DEBUG=TrueTEMPLATE_DEBUG=DEBUGADMINS=()MANAGERS=ADMINSTIME_ZONE='America/Chicago'LANGUAGE_CODE='en-us'SITE_ID=1USE_I18N=TrueMEDIA_ROOT=os.path.join(ROOT_PATH,'ui')MEDIA_URL='http://127.0.0.1:8000/media/'ADMIN_MEDIA_PREFIX='/admin_media/'SECRET_KEY='etcetcetc'TEMPLATE_LOADERS=()MIDDLEWARE_CLASSES=('django.middleware.common.CommonMiddleware',)ROOT_URLCONF='proxy_server.urls'TEMPLATE_DIRS=()INSTALLED_APPS=()
Then you also need to edit the project's urls.py, which is where the magic happens.
defproxy(request,url):conn=httplib2.Http()# optionally provide authentication for server#conn.add_credentials('admin','admin-password')ifrequest.method=="GET":url_ending="%s?%s"%(url,urlencode(request.GET))url=PROXY_FORMAT%url_endingresp,content=conn.request(url,request.method)returnHttpResponse(content)elifrequest.method=="POST":url=PROXY_FORMAT%urldata=urlencode(request.POST)resp,content=conn.request(url,request.method,data)returnHttpResponse(content)
You may have to change urls around a bit for your specific circumstances, but that's basically it.
Let me know if there any questions or problems. As mentioned, this is definitely a development solution, as all solutions involving the Django dev server are, and especially as all solutions with the Django dev server serving media are.
Take it with a few grains of salt. Or a lemon. Or a shot of tequila. Preferably not in that order.