creating my own context processor in django - django

Question

I have come to a point where I need to pass certain variables to all of my views (mostly custom authentication type variables).
I was told writing my own context processor was the best way to do this, but I am having some issues.
My settings file looks like this
TEMPLATE_CONTEXT_PROCESSORS = (
"django.contrib.auth.context_processors.auth",
"django.core.context_processors.debug",
"django.core.context_processors.i18n",
"django.core.context_processors.media",
"django.contrib.messages.context_processors.messages",
"sandbox.context_processors.say_hello",
)
As you can see, I have a module called 'context_processors' and a function within that called 'say_hello'.
Which looks like
def say_hello(request):
return {
'say_hello':"Hello",
}
Am I right to assume I can now do the following within my views?
{{ say_hello }}
Right now, this renders to nothing in my template.
My view looks like
from django.shortcuts import render_to_response
def test(request):
return render_to_response("test.html")

Answer 1

The context processor you have written should work. The problem is in your view.
Are you positive that your view is being rendered with RequestContext?
For example:
def test_view(request):
return render_to_response('template.html')
The view above will not use the context processors listed in TEMPLATE_CONTEXT_PROCESSORS. Make sure you are supplying a RequestContext like so:
def test_view(request):
return render_to_response('template.html', context_instance=RequestContext(request))

Answer 2

According to the django docs you can use render as a shortcut instead of render_to_response with the context_instance argument:
Alternatively, use the render() shortcut which is the same as a call to render_to_response() with a context_instance argument that forces the use of a RequestContext.

Answer 3

Let's say you have a file structure like this:
YourDjangoProject
├───project
│ ├───__init__.py
│ ├───asgi.py
│ ├───settings.py
│ ├───urls.py
│ └───wsgi.py
├───.env
├───manage.py
└───db.sqlite3
1) Anywhere, create a context_processors.py file
I'll create one in the project folder (with settings.py):
YourDjangoProject
└───project
├───...
└───context_processors.py
2) Create a function in context_processors.py that accepts a HttpRequest object as an argument and returns a dictionary
A context processor is just a function that accepts an HttpRequest object as an argument and returns a dictionary.
Like this:
# project/context_processors.py
def site_email(request):
return {'site_email': 'example#gmail.com'}
3) Add this to your context_processors setting in settings.py (at the bottom for security reasons)
TEMPLATES = [
{
'BACKEND': 'django.template.backends.django.DjangoTemplates',
'DIRS': [BASE_DIR / 'config' / 'templates'],
'APP_DIRS': True,
'OPTIONS': {
'context_processors': [
'django.template.context_processors.debug',
'django.template.context_processors.request',
'django.contrib.auth.context_processors.auth',
'django.contrib.messages.context_processors.messages',
'project.context_processors.site_email', # <- New context processor here
],
},
},
]
Now you'll be able to access the 'site_email' template variable on every single django template across your whole site.
Happy coding!

Answer 4

Since Django 1.8 you register your custom context processors like this:
TEMPLATES = [
{
'BACKEND': 'django.template.backends.django.DjangoTemplates',
'DIRS': [
'templates'
],
'APP_DIRS': True,
'OPTIONS': {
'context_processors': [
'django.template.context_processors.debug',
'django.template.context_processors.request',
'django.contrib.auth.context_processors.auth',
'django.contrib.messages.context_processors.messages',
'www.context_processors.instance',
],
},
},
]
assuming your context processor is in app www in context_processors.py

Answer 5

If you’re using Django’s render_to_response() shortcut to populate a template with the contents of a dictionary, your template will be passed a Context instance by default (not a RequestContext). To use a RequestContext in your template rendering, use the render() shortcut which is the same as a call to render_to_response() with a context_instance argument that forces the use of a RequestContext.