Django - How to Make a Variable Available to All Templates

Django - How to make a variable available to all templates?

What you want is a context processor, and it's very easy to create one. Assuming you have an app named custom_app, follow the next steps:

Add custom_app to INSTALLED_APPS in settings.py (you've done it already, right?);
Create a context_processors.py into custom_app folder;

Add the following code to that new file:

def categories_processor(request):
 categories = Category.objects.all()            
 return {'categories': categories}

Add context_processors.py to TEMPLATE_CONTEXT_PROCESSORS in settings.py

TEMPLATE_CONTEXT_PROCESSORS += ("custom_app.context_processors.categories_processor", )

And now you can use {{categories}} in all the templates :D

As of Django 1.8

To add a TEMPLATE_CONTEXT_PROCESSORS, in the settings you must add the next code:

TEMPLATES[0]['OPTIONS']['context_processors'].append("custom_app.context_processors.categories_processor")

Or include that string directly in the OPTIONS.context_processors key in your TEMPLATES setting.

How do I pass variables to all templates in django?

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.

How to set a value of a variable inside a template code?

You can use the with template tag.

{% with name="World" %}     
<html>
<div>Hello {{name}}!</div>
</html>
{% endwith %}

django variable available to all the views

You may want to implement a custom Middleware.

https://docs.djangoproject.com/en/dev/topics/http/middleware/

This lets you execute custom code for every request and attach the results to the request object, which is then accessible in your view.

Having a global variable available to your templates in Django

Django has a standard way for implementing this, which is context processors. This article provides an example implementation
https://www.webforefront.com/django/setupdjangocontextprocessors.html.

Actually a context processor is just a function that accepts a request object and returns a dict with the data you want.

How do I get all the variables defined in a Django template?

Both Ned's and blaine's answers are good, but if you really want to achieve exactly what you ask for there's a template tag for it:

{% debug %}

Builtins:debug

More information in the context_processor.debug including:

If this processor is enabled, every RequestContext will contain debug
and and sql_queries variables – but only if your DEBUG setting
is set to True and the request’s IP address (request.META['REMOTE_ADDR'])
is in the INTERNAL_IPS setting

Similar to Peter G suggestion, I often use a <div id="django-debug"><pre>{% debug|escape %}</pre></div> block at the end of the page that has display:none but that I can inspect to debug.

Django - How to Make a Variable Available to All Templates