How do I pass variables to all templates in django

问题:

This question already has answers here:

Django - How to make a variable available to all templates? (2 answers)

Closed 4 years ago.

I am trying to pass variables (browser variable) to all my templates in my app. Any advice on how to get it to work?

View:

def browser(request):
    primary_cat_list = Categories.objects.order_by("category")
    subcat_list = SubCategories.objects.order_by("sub_category")
    product = Productbackup.objects.order_by("website")
    browser =  list(chain(primary_cat_list, subcat_list, product))
    return render_to_response('reserve/templates/base.html', locals(), context_instance=RequestContext(request))

Template:

{% for prod in browser %} {{ prod }}, {% endfor %}

回答1:

You, my friend, are in the market for Context Processors.

From a blog entry written by a far nimbler and erudite technical writer than I:

What are template context processors?

Django’s context processors are a facility that allows you to provide data and callbacks to your templates.

You can do so in one of two ways:

• On an individual request basis: by passing a custom Context value to your render_to_response() call
• Globally: by creating a context processor method that accepts a HttpRequest object as input, and returns a payload or callback, then registering the context processor in your settings.py, then providing your render_to_response() call with the built-in RequestContext attribute instead of your own (you can always extend RequestContext to add more data on an individual request basis of course).

If that approach for passing data to templates sounded absurd and obfuscated to you, you’re not alone. The complexity involved in such a simple operation is unwarranted and counter-productive, but every system has its shortcomings.

The official documentation is here:

https://docs.djangoproject.com/en/dev/ref/templates/api/

So but yeah, I have been programming with Django for a while, and one of the reasons I really like solving problems w/ it is because it is almost Byzantine in its complexity, but not in a domineering sort of way. It has a ton of geegaws and doodads that may not immediately appear useful; each of these either comes in extremely handy when you need it, and it will stay out of your way if not.

The upshot here for you is: context processors are a fine example of those. Yes.

回答2:

Currently you're passing locals() as the variable scope which should include browser aswell, but I find the use of locals() very ugly.

Personally I always prefer a pattern like this instead:

def browser(request):
    context = RequestContext(request)

    primary_cat_list = Categories.objects.order_by("category")
    subcat_list = SubCategories.objects.order_by("sub_category")
    product = Productbackup.objects.order_by("website")
    browser =  list(chain(primary_cat_list, subcat_list, product))

    context['browser'] = browser

    return render_to_response('reserve/templates/base.html', context_instance=context)

回答3:

I can give you an example of my code, that works fine. Here is the file named context_processors.py:

context_processors.py

def base(request):
    user = request.user

#======================
#Login form
#=====================

# here is the code for login user or check if he is logged in already

return  {
        'user': user,
        }

and that's, part of my base.html (a template that I use wor all my pages)

base.html

{% if user.username %}
                    <h3>
                        Welcome {{ user.username }}
                    </h3>