Content-Range configuration for Django Rest Pagination - dojo

Question

6.30.15 - HOW CAN I MAKE THIS QUESTION BETTER AND MORE HELPFUL TO OTHERS? FEEDBACK WOULD BE HELPFUL. THANKS!
I need to send a content-range header to a dojo/dgrid request:
I cannot find any examples of HOW to do this. I'm not exactly sure where this setting goes (Content-Range: items 0-9/*). I have been given a great linkheaderpagination example on this question: Django Rest Framework Pagination Settings - Content-Range But I don't know how to make this work to produce a Content-Range response. Any takers or does anyone know of any good resources or examples??
UPDATE: I am trying to create pagination in Dojo/grid. I have am using a server-side api (Django Rest Framework) to supply to data to the Dojo/Dgrid. Django Rest Framework does not automatically sent content-range headers when it gets a response from Dojo. Dojo sends a range request when formatted to have pagination. I don't know now to configure the Django Rest Framework API to send a content-range header when it gets a request from Dojo. Unfortunately, I'm trying to do something very specific and just general settings on either side doesn't work.

Answer 1

Including Content-Range Header in response:
You just need to create a headers dictionary with Content-Range as the key and value as how many items are being returned and how many total items exist.
For example:
class ContentRangeHeaderPagination(pagination.PageNumberPagination):
"""
A custom Pagination class to include Content-Range header in the
response.
"""
def get_paginated_response(self, data):
"""
Override this method to include Content-Range header in the response.
For eg.:
Sample Content-Range header value received in the response for
items 11-20 out of total 50:
Content-Range: items 10-19/50
"""
total_items = self.page.paginator.count # total no of items in queryset
item_starting_index = self.page.start_index() - 1 # In a page, indexing starts from 1
item_ending_index = self.page.end_index() - 1
content_range = 'items {0}-{1}/{2}'.format(item_starting_index, item_ending_index, total_items)
headers = {'Content-Range': content_range}
return Response(data, headers=headers)
Suppose this is the header received:
Content-Range: items 0-9/50
This indicates that first 10 items are returned out of total 50.
Note: You can also use * instead of total_items if calculating total is expensive.
Content-Range: items 0-9/* # Use this if total is expensive to calculate

Answer 2

If you are talking about providing Content-Range in the response, I mentioned in an answer to another SO question (which I believe may also have originated from your team?) that there is one alternative to this header: if your response format is an object (not just an array of items), it can specify a total property indicating the total number of items instead.
Again looking for a few minutes at the DRF documentation, it appears it should be possible to customize the format of the response.
Based on the docs and reading the source of LimitOffsetPagination (which you want to be using to work with dstore, as already discussed in a previous question), if I had to take a wild guess, you should be able to do the following server-side:
class CustomPagination(pagination.LimitOffsetPagination):
def get_paginated_response(self, data):
return Response(OrderedDict([
('total', self.count),
('next', self.get_next_link()),
('previous', self.get_previous_link()),
('items', data)
]))
This purposely assigns the count to total and the data to items to align with the expectations of dstore/Request. (next and previous are entirely unnecessary as far as dstore is concerned, so you could take or leave them, depending if you have any use for them elsewhere.)