Refactor filterforms in list Views

[mina-atef-00]

Type of Issue: Code refactor

Steps to Reproduce:

• Visit a list view page.

Expected Behavior:

• Fully serialized response that works with DRF browsable API.

Current Behavior:

• On http://localhost:8000/harvest for example
  • Browsable api enabled: I get this error: Feature 307 integrate drf browsable api #317 (comment)
  • Normal html response uses get_filter_context() and 'new' which could be reversed.

Code Snippets:

1. HarvestViewset.list() context (without serializer output):

{'filter': {'form': <HarvestFilterForm bound=True, valid=Unknown, fields=(status;pick_leader;trees;property__neighborhood;season)>},
 'new': {'title': 'New Harvest', 'url': '/harvest/create/'}}

Related URLs:

https://localhost:8000/harvest/
And the rest of the list views.

[mina-atef-00]

Tasks:

• Add 'new' to the response.data of the serializers.
• refactor get_filter_context()

[mina-atef-00]

hi @2ynn,
I'm running into a problem with the listviews context:
in the CommunityViewset for example:

class CommunityViewset(LoginRequiredMixin, viewsets.ModelViewSet):

    ...

    def list(self, request, *args, **kwargs):
        response = super(CommunityViewset, self).list(request, *args, **kwargs)
        if request.accepted_renderer.format == 'json':
            return response
        # default request format is html:
        return Response(
            {
                'data': response.data,
                'filter': get_filter_context(self),
                ######################!!!!!!!!!!!!!
                'new': { 
                    'url': reverse_lazy('person-create'),
                    'title': _("New Person")
                    }
            }
        )

---

To enable the html filtering in DRF browsable api, I have to return only the serializer output:

So when it comes to 'new' (data provided for the "New Person" btn) I can't pass it to the serialzer.

If I for example add a new serializermethodfield returning a "new" dictionary-because this is a list view-it will add the 'new' data to every instance in the output:

Do you know what can be done to solve this?

[2ynn]

@mina-andajos have you looked into the to_representation method to add additional context to serializer only once (not once per object)?
https://www.django-rest-framework.org/api-guide/relations/#custom-relational-fields

[2ynn]

for example you could do something like this:

class MySerializer(serializers.ModelSerializer):
[...]
    def to_representation(self, obj):
        ord_dic = super().to_representation(obj)
        ord_dic['new'] = "new_data"
        return ord_dic

And the 'new' field would be added only once, not for all objects

This is nice when you have nested serializers (with many=True) but it might not be what you are looking for in the case of a list view. Instead you can pass additional context to the Viewset using get_serializer_context:

  def get_serializer_context(self):
        context = super().get_serializer_context()
        context['new'] = "new_data"
        return context

https://stackoverflow.com/questions/39202380/django-rest-framework-how-to-add-context-to-a-viewset

[mina-atef-00]

hi @2ynn ,

1- I tried the to_representation() before, it does the same thing as adding a new method field, it adds 'new' to every instance in the serializer output:

[
    {
        "id": 3,
        "person": {
            "actor_id": 4,
            "name": "Mina Andajos",
            ...
        "new": {
            "url": "/person/create/",
            "title": "New Person"
        }
    },
    {
        "id": 2,
        "person": {
        #!!!!! another new below

2- I also found that the JSON list response of the serializer doesn't work with the HTML templates as they expect a dict.

3- I followed the stackoverflow link you provided as well but I'm still facing the same error above.

---

I'm thinking of this method to fix these problems:

• I could make the list functions check for the template rendering engine (whether we're using the browsable api or the html templates)
• And then switch to the default serializer list output when we're using the browsable api. And just the default context when using the templates.
• Therefore the filter button will work on the browsable api. And the html template rendering will work normally.

What do you think?