Tastypie, add element to a many to many relationship

django, rest, tastypie

Solution

I implemented this by overriding the save_m2m function of the API Resource. Here is an example using your models.

def save_m2m(self, bundle):
    for field_name, field_object in self.fields.items():
        if not getattr(field_object, 'is_m2m', False):
            continue

        if not field_object.attribute:
            continue

        if field_object.readonly:
            continue

        # Get the manager.
        related_mngr = getattr(bundle.obj, field_object.attribute)
            # This is code commented out from the original function
            # that would clear out the existing related "Person" objects
            #if hasattr(related_mngr, 'clear'):
            # Clear it out, just to be safe.
            #related_mngr.clear()

        related_objs = []

        for related_bundle in bundle.data[field_name]:
            # See if this person already exists in the database
            try:
                person = Person.objects.get(name=related_bundle.obj.name)
            # If it doesn't exist, then save and use the object TastyPie
            # has already prepared for creation
            except Person.DoesNotExist:
                person = related_bundle.obj
                person.save()

            related_objs.append(person)

        related_mngr.add(*related_objs)

Problem

I'm building a django tastypie api, and I have a problem with adding elements in `ManyToMany` relationships Example, models.py ``` class Picture(models.db): """ A picture of people""" people = models.ManyToManyField(Person, related_name='pictures', help_text="The people in this picture", ) class Person(models.db): """ A model to represet a person """ name = models.CharField(max_length=200, help_text="The name of this person", ) ``` resources: ``` class PictureResource(ModelResource): """ API Resource for the Picture model """ people = fields.ToManyField(PersonResource, 'people', null=True, related_name="pictures", help_text="The people in this picture", ) class PersonResource(ModelResource): """ API Resource for the Person model """ pictures = fields.ToManyField(PictureResource, 'pictures', null=True, related_name="people", help_text="The pictures were this person appears", ) ``` My problem is that I would like to have an `add_person` end point in my picture resource. If I use `PUT`, then I need to specify all the data in the picture If I use `PATCH`, I still need to specify all the people in the picture. Of course I could simply generate the `/api/picture/:id/add_people` URL and there I could handle my problem. The problem with that is that it does not feel clean. Another solution would be to generate the `/api/picture/:id/people` end point, and there I could do `GET`, `POST`, `PUT`, like it's a new resource, but I don't know how to implement this and it seems strange to create new people under this resource. Any thoughts?

Original source