Question

I am trying to implement paging across ajax calls. The page should not refresh when the user wants to see the next x num of results.

Here is my problem. Returning the QuerySet is super simple. I just do (sumaJson is custom)

data = serializers.serialize('sumaJson', result_page.object_list, relations=('first_major', 'country_of_origin', 'second_major'))
return HttpResponse(data, mimetype="application/json") 

Now I also want to return things like

result_page.has_previous()
result_page.has_next()
result_page.paginator.count

and so on. I for the life of me can’t figure out how to get both across in one response. I can’t add this info to result_page.object_list because then the serializer fails. If I something of the sort of

simplejson.dumps(paging_info + result_page.object_list)

Then in the javascript the QuerySet is no longer a list of objects but just a big string of characters which can’t be interpreted with

$.each(data.data, function(index, item){

I tried some bad hacks like creating a fake object and putting it in the object_list, serializing this and then deleting the object. This allows me to get the data across. However, I don’t want to be creating and deleting fake objects.

I don’t want to meddle with the serializer. I don’t want to send a second ajax request once I get the querySet back to get the paging info.

Am I missing something? Is there an easy way to get both across in one response? Thanks!

Answer 1

When I’m serializing a collection of objects, I typically include the pagination information in the response body itself. If I had 50 objects that I wanted to serve up 10 per page, the JSON would look something like this:

{
    "count": 50,
    "objects": [
        {
            ...
        }
    ],
    "pages": {
        "count": 5,
        "current": "http://api.example.com/objects/?page=3",
        "first": "http://api.example.com/objects/",
        "last": "http://api.example.com/objects/?page=5",
        "next": "http://api.example.com/objects/?page=4",
        "previous": "http://api.example.com/objects/?page=2"
    }
}