Issue with relationships in POST/PATCH/PUT requests

[martinmaillard]

If I do a POST request with data containing a relationship:

{
    "data": {
        "type": "comments",
        "attributes": {
            "body": "Hi"
        },
        "relationships": {
            "entry": {
                "data": {
                    "id": "12",
                    "type": "entries"
                }
            }
        }
    }
}

I get the following error:

{
    "errors": [{
        "status": "400",
        "source": {"pointer": "/data/attributes/entry"}, 
        "detail": "Incorrect type. Expected pk value, received OrderedDict."
    }]
}

I understand why this is happening, but I think this is a mistake.

[martinmaillard]

This behaviour seems to have been introduced in d654c75

[jerel]

It looks like this is probably a documentation bug on our part: you need to use ResourceRelatedField (from rest_framework_json_api.relations) for your relationship fields so it knows how to parse the incoming compound document

[jsenecal]

@martinmaillard, @jerel is right - i introduced ResourceRelatedField to be able to parse things properly: 23d0af6

See issue #111

[jsenecal]

We could also override the serializer_related_field in both HyperlinkedModelSerializer and ModelSerializer so that we use the ResourceRelatedField by default, but in the case of HyperlinkedModelSerializer we would also need to override a few of the methods provided by DRF to supply the proper links.

[martinmaillard]

Ok thank you, I didn't know that :)

Now it's working, but I still have an issue with the type validation... ResourceRelatedField is way too rigid when it checks the valid type. It gets the expected type from the queryset, which means that:

• it's not possible to customize the type of a relation (what is allowed by the resource_name on the serializer)
• it's not possible to allow multiple types to be valid for one relation (useful with polymorphic relationships)

[jsenecal]

@martinmaillard I'm open to suggestions and PRs if you find a better way to validate the type as I am going to be busy for some time.

The expected type verification is done here: https://github.com/django-json-api/django-rest-framework-json-api/blob/develop/rest_framework_json_api/relations.py#L110 - have fun ;)

[jsenecal]

I also think we should create a new issue for the behavior you are describing as it is out of the topic of this one.

This issue is a duplicate of #111, I will now close it.

[martinmaillard]

I will think about it, but it's a complicated issue. These types are all over the place and we need to centralize the way we generate/validate them.

Anyway thank you for your quick answers !

[jsenecal]

No worries - also this issue made us realize we really need to document those features - I'll create a new one for that.

[riklaunim]

How the ResourceRelatedField should be used? I still get that the related object is "places" instead of "Place" when creating an object with relation to Place.

[riklaunim]

Any update on this? I would say expected type should not be the model name - https://github.com/django-json-api/django-rest-framework-json-api/blob/develop/rest_framework_json_api/relations.py#L119 as everywhere else it's plural lowercase version of it.

[jerel]

@riklaunim here is an example of the ResourceRelatedField in use: https://github.com/django-json-api/django-rest-framework-json-api/blob/develop/example/serializers.py#L40-L41 If you could create a test that shows the unexpected behavior and open a PR we could discuss it better.

[riklaunim]

ok, I missed two things ;)

JSON_API_FORMAT_RELATION_KEYS = 'dasherize'
JSON_API_PLURALIZE_RELATION_TYPE = True

And it works.