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    <p>In my opinion the cleanest place for the code you need is as a new Manager method (eg from_json_string) on a custom manager for the NinjaData model.</p> <p>I don't think you should override the standard create, get_or_create etc methods since you're doing something a bit different from what they normally do and it's good to keep them working normally.</p> <p><strong>Update:</strong> I realised I'd probably want this for myself at some point so I have coded up and lightly tested a generic function. Since it recursively goes through and affects other models I'm no longer certain it belongs as a Manager method and should probably be a stand-alone helper function.</p> <pre><code>def create_or_update_and_get(model_class, data): get_or_create_kwargs = { model_class._meta.pk.name: data.pop(model_class._meta.pk.name) } try: # get instance = model_class.objects.get(**get_or_create_kwargs) except model_class.DoesNotExist: # create instance = model_class(**get_or_create_kwargs) # update (or finish creating) for key,value in data.items(): field = model_class._meta.get_field(key) if not field: continue if isinstance(field, models.ManyToManyField): # can't add m2m until parent is saved continue elif isinstance(field, models.ForeignKey) and hasattr(value, 'items'): rel_instance = create_or_update_and_get(field.rel.to, value) setattr(instance, key, rel_instance) else: setattr(instance, key, value) instance.save() # now add the m2m relations for field in model_class._meta.many_to_many: if field.name in data and hasattr(data[field.name], 'append'): for obj in data[field.name]: rel_instance = create_or_update_and_get(field.rel.to, obj) getattr(instance, field.name).add(rel_instance) return instance # for example: from django.utils.simplejson import simplejson as json data = json.loads(ninja_json) ninja = create_or_update_and_get(NinjaData, data) </code></pre>
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    1. COI have to move on with my work, so i am already making custom managers for my models, and i am already using a custom method inside it called create_or_update_and_get (name explains what it does), it takes the python object generated from json.loads(ninja_data) and using some 20-30 lines of magic returns an existing(updated) or newly created model instance. it is working out ok, but to be able to use standard methods like filter for lookups, i still have to override filter method. +1 for pointing exactly what i am doing, meanwhile, i am still looking for a more natural, scalable approach.
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    2. COI don't quite get why you have to override filter for lookups? I guess to make the manage method more generic you could look through Manager.model._meta.fields for instances of ManyToMany and match those to keys in the json with list values, same for ForeignKey and keys with dict values. For each field you can get the related model class from eg `Manager.model._meta.fields[index].rel.to` and then get_or_create the related instances generically.
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    3. COhave coded the above suggestion and edited my answer to include it...
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