Installation

pip install -e git+https://github.com/night-crawler/drf-metadata.git@#egg=drf-metadata

Models

class Author(models.Model):
    name = models.CharField(max_length=255)
    birth = models.DateField('birth date')

    def __str__(self):
        return self.name


class Publisher(models.Model):
    name = models.CharField(max_length=255)
    state = models.PositiveSmallIntegerField(
        'publisher state',
        choices=(
            (0, 'Active'),
            (1, 'Disabled')
        ),
        default=1
    )

    def __str__(self):
        return self.name


class Book(models.Model):
    title = models.CharField(max_length=255)
    authors = models.ManyToManyField(Author)
    publisher = models.ForeignKey(Publisher)

Usage

from drf_metadata.meta import MetaData, AbstractField, CustomMetadata

class BookMetadata(MetaData):
    model = Book

    serializers = {
        'publisher': PublisherSerializer
    }

    update_fields = {
        'authors': {
            'omg': {'lol': 1}
        }
    }

    # skip serialization (don't include model instances to choice field)
    dataset_urls = {
        'authors': '/author/',
        'publisher': '/publisher/',
    }

    # custom queryset for instance (self has `obj` if you need to filter qs)
    def get_authors_queryset(self, field):
        return Author.objects.filter(name='author0')

    # use custom serializer for field instance(s)
    def get_authors_serializer(self, field):
        # self.request, self.view, self.obj are available in MetaData instance
        return AuthorSerializer

    # update field bundle with runtime values
    def update_authors_field_meta(field, obj):
        return {'new': 1, 'obj': str(obj)}

    # use own serializer
    def get_publisher_field_meta(field, obj):
        return {'new': 1, 'obj': str(obj)}

Usage with django-rest-framework

# or redefine OPTIONS handler
class BookViewSet(viewsets.ReadOnlyModelViewSet):
    @list_route()
    def describe_book(self, request):
        md = metadata.BookMetadata().determine_metadata(request, self)
        return Response(md)

Sample response

{
    "title": "book", "description": "description",
    "fields": [
        {
            "type": "CharField", "max_length": 255,
            "name": "title",
            "verbose_name": "title",
            "help_text": "", "blank": false, "null": false, "editable": true, "required": true},
        {
            "type": "ForeignKey",
            "name": "publisher", "verbose_name": "publisher", "help_text": "",
            "blank": false, "null": false, "editable": true, "required": true,
            "data": [
                {"id": 47, "name": "pub0"},
                {"id": 48, "name": "pub1"},
                {"id": 49, "name": "pub2"}
            ]
        },
        {
            "type": "ManyToManyField",
            "name": "authors", "verbose_name": "authors", "help_text": "",
            "blank": false, "null": false, "editable": true, "required": true,
            "data": [
                {"id": 37, "name": "author0"},
                {"id": 38, "name": "author1"},
                {"id": 39, "name": "author2"}
            ]
        }
    ]
}

Non-model MetaData

class ImpersonateMetadata(CustomMetadata):
    title = 'View site as another user'
    action_name = 'Impersonate'

    fields = (
        AbstractField(type='ForeignKey',
                      name='user_id',
                      verbose_name='User',
                      data='/data/',
                      required=True),
    )

    # method fields
    def get_superfield(self, request):
        return {
            'name': 'hero',
            'super': True
        }

    def get_lol(self, request):
        return {
            'name': 'lol',
            'super': False
        }

    # update field `user_id`
    def get_field_user_id(self, field_name, request):
        return {
            'lol': 1
        }