Django-tastypie and many of the many end-to-end relationships

Question

In Django and Tastypie, I am trying to figure out how to handle many many cross-cutting relationships, such as those found here: https://docs.djangoproject.com/en/dev/topics/db/models/#extra-fields- on-many-to-many-relationships

Here are my sample models:

class Ingredient(models.Model): name = models.CharField(max_length=100) description = models.TextField() class RecipeIngredients(models.Model): recipe = models.ForeignKey('Recipe') ingredient = models.ForeignKey('Ingredient') weight = models.IntegerField(null = True, blank = True) class Recipe(models.Model): title = models.CharField(max_length=100) ingredients = models.ManyToManyField(Ingredient, related_name='ingredients', through='RecipeIngredients', null = True, blank = True) 

Now my api.py file:

 class IngredientResource(ModelResource): ingredients = fields.ToOneField('RecipeResource', 'ingredients', full=True) class Meta: queryset = Ingredient.objects.all() resource_name = "ingredients" class RecipeIngredientResource(ModelResource): ingredient = fields.ToOneField(IngredientResource, 'ingredients', full=True) recipe = fields.ToOneField('RecipeResource', 'recipe', full=True) class Meta: queryset= RecipeIngredients.objects.all() class RecipeResource(ModelResource): ingredients = fields.ToManyField(RecipeIngredientResource, 'ingredients', full=True) class Meta: queryset = Recipe.objects.all() resource_name = 'recipe' 

I am trying to create code in this example: http://pastebin.com/L7U5rKn9

Unfortunately, with this code, I get this error:

 "error_message": "'Ingredient' object has no attribute 'recipe'" 

Does anyone know what is going on here? Or how can I include an ingredient name in a RecipeIngredientResource? Thanks!

EDIT:

Perhaps I myself found a mistake. ToManyField should be directed to the Ingredient, and not to the RecipeIngredient. I'll see if this can handle this.

EDIT:

New mistake .. any ideas? Object '' has an empty attribute 'title' and does not accept default or null values.

Answer 1

You mentioned:

Perhaps I myself found a mistake. ToManyField should be directed to the Ingredient, and not to the RecipeIngredient. I will see if this task is completed.

There is a better approach though [Tastypie M2M] ( http://blog.eugene-yeo.in/django-tastypie-manytomany-through.html ) (old blog disabled: https://github.com/9gix/eugene-yeo .in / blob / master / content / web / django-tastiepie-m2m.rst )

In short, instead of ToManyField for ingredients, I use ToManyField to ThroughModel . And configure attribute kwargs as a callback function that returns a Queryset ThroughModel .

Update (April 2014)

This answer is made a long time ago. Not sure if it is still useful.

Answer 2

I had the same problem as you. To solve this problem, I simply removed the ToMany field (as in RecipeResource) from the API. This worked for us, as the model still had a manytomany field (and not an API), and you can still request a relationship by requesting an intermediate model.