django url parse formatted url - django

Question

I'm in the design stages of a single page web app, and would like to make it so that a user can click on a formatted URL and the data requests will load in the page.
For example, a url of http://www.mysite.com/?category=some_cat will trigger the Category view with the relevant data.
My intention is to parse the URL, gather the data, then pass it to the index.html template for rendering on page load. Once the page has been loaded, a Javascript trigger setting will trigger the appropriate button to load the client view.
However, I'm having an issue setting up the URL parser, as the following settings are not matching the example url above.
from app.views import app_views, photo_views, user_views, admin_views
urlpatterns = patterns("",
url(r'^/(?P<category>\d+)/$', app_views.index)
)

Answer 1

You're confusing between sending information through your urls with GET and formatting you urls with arguments for the view functions. Say I am visiting a site called http://www.mysite.com/ and the page has a form that looks like this:
<form>
<input type='text' name='category' id='category'></input>
<button type='submit'>Send!</button>
</form>
upon clicking, the url will automatically change to http://www.mysite.com/?category=<value of input>. The ? marks that everything afterwards should be treated as GET data, with the syntax of <id>=<value>. You can then access them like so:
def response(request):
category = request.GET['category']
formatting urls is different, because it means looking for patterns that are part of the url. i.e. a pattern that looks like r'^/(?P<category>\d+)/$' will look for this: http://www.mysite.com/<category>/ and it will send it to the request in your views as an additional argument like so:
def response(request, category):
...
The regex is used to define how you recognize that part of the url. For example, the \d+ you're using means that category needs to be a number. You can search how to define different types of patterns according to your needs
Note that with GET you are sending the data to the same view function that rendered the page you are currently visiting, while using a different url means you tell it where to go through your urls.py (usually a different function). Does that make things a bit clearer?