如何在direct_to_template或urls.py中的简单视图中提供会话数据（不创建应用）

Question

I'm working on a site where many pages don't need any logic and are rendered via direct_to_template in urls.py, like so:

url('^support/slp/$',
    direct_to_template, {
        'template': 'pages_fixed/support/support_slp.html',
        'extra_context': {
            'questions':  Question.objects.filter(show_slp=True).order_by('seq_num'),
            'user_state': request.session['user_state'],   # <-- tried adding, no go
        }
    },
    name='support'
),

A new requirement came up which requires me to check the state of a session var in most of these pages, to render different bits of the template. I tried supplying the request object but obviously, it's not available in the urls.

I know that I can try creating a new 'app' for each such page (or, say, category of pages) and then provide the session var in each view.py view function. However, this seems really excessive given how many pages there are, and I only need this one var available.

What would be the simplest (most light-weight) solution?

Answer 1

Its about time you started using the generic class based views , which will automatically pass in the request context , which will make session data available in your templates.

You will have to enable the template request context processor which will give you a {{ request }} variable at the template level.

Here is an example using ListView :

from django.conf.urls import patterns
from django.views.generic.list import ListView

urlpatterns = patterns('',
    (r'^support/slp/$',
        ListView.as_view(template_name="pages_fixed/support/support_slp.html",
                         queryset=Question.objects.filter(show_slp=True).order_by('seq_num')),
)

In your support_slp.html template, you'll have a object_list variable that will be result of the queryset and you can use {{ request.session.user_state }} in the template.

Answer 2

This could easily be done in a custom template tag. Inclusion and assignment tags can optionally accept the existing context, which includes the request if you have the request context processor activated. You can use that to access the session.

Answer 3

You could use a custom context processor to feed whatever you need into the context of all the pages. Suppose you put this code in package_name/context_processors.py

def session_data(request):
    return {
        'user_state': request.session['user_state'],
    }

The you specify this context processor in TEMPLATE_CONTEXT_PROCESSORS in the settings file:

TEMPLATE_CONTEXT_PROCESSORS = (
    'django.contrib.auth.context_processors.auth',
    'django.core.context_processors.request',
    'django.core.context_processors.debug',
    'django.core.context_processors.i18n',
    'django.core.context_processors.media',
    'django.core.context_processors.static',
    'django.core.context_processors.tz',
    'django.contrib.messages.context_processors.messages',
    'package_name.context_processors.user_data')

More documentation on context processors available here