Parsing query params in rest-framework

It has always bothered me that you have to parse query parameters manually in django-rest-framework views, and there is no generic way to do it.

The old way

Basically I used to do it like this:

class MyView(APIView):
    def get(request):
        count = request.QUERY_PARAMS.get('count', None)
        if count is None:
            return Response(status=status.HTTP_400_BAD_REQUEST)
        try:
            count = int(count)
        except ValueError:
            return Response(status=status.HTTP_400_BAD_REQUEST)

        # do your work

This is the most tedious, repetetive and error prone method of parsing query params I can imagine, yet my code is liberally sprinkled with it. Why?

We'll basically, for some weird reason I kept thinking: hmm... serializers? they're good for POST. After a brief talk with Tom Christie I kept scratching my head and thinking why I did not figure this out myself!

Serializers are good for any dict

And they are really well suited for parsing request.QUERY_PARAMS and they save you plenty of lines.

The superb new way of doing this:

class MyQueryParamsExpectations(serializers.Serializer)
    count = fields.IntegerField()

class MyView(APIView):
    def get(request):
        qpe = MyQueryParamsExpectations(data=request.QUERY_PARAMS)
        if not qpe.is_valid():
            return Response(
                data=qpe.errors,
                status=status.HTTP_400_BAD_REQUEST
            )
        qp = qpe.object

        # do your work and be happy with less code :)

This is actually uber-awesome, because you can easily reuse query params serializers between multiple views.

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