Django - update custom context in view - django

Question

I have a custom context processor that passes some server side constants to the client (by injecting into javascript object). Some views might want to add additional params, notifications for example, to the dict.
from django.contrib.sites.shortcuts import get_current_site
def client_context(request):
params = {}
domain = get_current_site(request).domain
schema = request.scheme
params['rooturl'] = "%s://%s" % (schema,domain)
return {'params': params}
According to the docs
When context processors are applied
Context processors are applied after the context itself is processed. This means that a context processor may overwrite variables you’ve supplied to your Context or
RequestContext, so take care to avoid variable names that overlap with
those supplied by your context processors.
If I render a template without overriding params it's working fine - i get the baseurl in the template.
If I render the template with a variable named params i get only the overrided value.
def home(request):
return render(request, 'home.html', { 'params' : {'page' : 'home'} })
so i have two questions
Is the django docs incorrect ? from what i understand the second
dict should update the first one. According to these findings my
custom context is applied first.
What is the best way to achieve this ?
EDIT
In my base.html file (extended by all other templates) i pass the params object to a Js objects. e.g
{% block init %}
<script>
Global = new Global( {{ params | json }} );
</script>
{% endblock %}
I was hoping for a solution that wont require adding each possible parameter by name
{% block init %}
<script>
Global = new Global( { baseurl : "{{baseurl}}", page : "{{ page }}" );
</script>
{% endblock %}

Answer 1

Django is working as documented. The params returned by your template context processor is overwriting the params in the view's context. Django doesn't automatically merge dictionaries as you want.
Instead of using the render shortcut, you could make your views return TemplateResponse objects. Then, instead of writing a context processor, write a middleware that updates the params dict in the process_template_response method.