Tastypie Inline (aka. Nested, full=True, Embedded) Relationship Dynamically via GET Parameter

I believe this tutorial to be best motivated by an example.  The example relationships below are from a conference app.  A conference app will have presenters (persons) and a schedule with multiple tracks.

api/v1/conference_app/3/?format=json

{
    "persons": [
        "/api/v1/person/35/",
        "/api/v1/person/36/"
    ],
    "resource_uri": "/api/v1/conference_app/3/",
    "summary": "test",
    "tracks": [
        "/api/v1/track/6/",
        "/api/v1/track/7/"
    ]
}

api/v1/conference_app/3/?format=json&inline=true

{
    "persons": [
        {
            "conference_id": "/api/v1/conference_app/3/",
            "description": "",
            "id": "35",
            "person_image": null,
            "person_name": "",
            "resource_uri": "/api/v1/person/35/"
        },
        {
            "conference_id": "/api/v1/conference_app/3/",
            "description": "",
            "id": "36",
            "person_image": null,
            "person_name": "",
            "resource_uri": "/api/v1/person/36/"
        }
    ],
    "resource_uri": "/api/v1/conference_app/3/",
    "summary": "test",
    "tracks": [
        {
            "conference_id": "/api/v1/conference_app/3/",
            "id": "6",
            "resource_uri": "/api/v1/track/6/",
            "schedule_entries": [],
            "track_name": "test1"
        },
        {
            "conference_id": "/api/v1/conference_app/3/",
            "id": "7",
            "resource_uri": "/api/v1/track/7/",
            "schedule_entries": [],
            "track_name": ""
        }
    ]
}

This tutorial will allow the user of an API to dynamically specify that a resource be either inlined or accessed via a resource_uri.

Tastypie is not capable of changing the fields model values dynamically.  The below model inherits from the model ToManyFields which itself inherits from the model Field.  Overriding the method dehydrate_related inherited from the model Field allows us to change the dehydration behavior based on the passed in bundle.request.

class ToManyFieldInlineToggle(fields.ToManyField):
    def dehydrate_related(self, bundle, related_resource):
        try:
            isInline = bundle.request.GET.get('inline')
            if isInline not in [ 'true', 'True', True]:
                return related_resource.get_resource_uri(bundle)
        # bundle.request is None
        except NoneType:
            pass

        # Default non-nested behavior
        bundle = related_resource.build_bundle(obj=related_resource.instance, request=bundle.request)
        return related_resource.full_dehydrate(bundle)

Then, instead of using field.ToManyField() within your models that inherit from ModelResource, use ToManyFieldInineToggle().

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