implementing custom backend is not recognized by django

Following the usually smart answer from one of djangos experts I want to implement my own backend, overwriting SQLite3 and Postgres JSON handling method.

What I did:

1. created a backends folder in my app directory:
   

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2. put base.py in there

   from django.db.backends.base.operations import BaseDatabaseOperations
   from django.db.backends.sqlite3.base import DatabaseWrapper as DBW
   import json
   
   class BaseDatabaseOperationsJSON(BaseDatabaseOperations):
       def adapt_json_value(self, value, encoder):
           print("should be called")
           return json.dumps(value, ensure_ascii = False, cls = encoder)
   
   
   class DatabaseWrapper(DBW):
       ops_class = BaseDatabaseOperationsJSON
   

3. changed settings.py accordingly (so I thought):

   DATABASES = {
       'default': {
           'ENGINE': "Shelf.backends.sqlite3json",
           'NAME': BASE_DIR.joinpath("db.sqlite3"),
       }
   }
   

This throws the error:

NotImplementedError: subclasses of BaseDatabaseOperations may require a quote_name() method

>Solution :

I think you were quite close, you should only subclass the operations class of sqlite3 since it contains already logic how to quote names, etc:

import json

from django.db.backends.sqlite3.base import DatabaseWrapper as DBW
from django.db.backends.sqlite3.operations import DatabaseOperations


class BaseDatabaseOperationsJSON(DatabaseOperations):
    def adapt_json_value(self, value, encoder):
        return json.dumps(value, ensure_ascii=False, cls=encoder)


class DatabaseWrapper(DBW):
    ops_class = BaseDatabaseOperationsJSON