Snippet

Dynamic Model Field Injection via Metaclass Class Decorators

Django model structures can be dynamically augmented using the internal contribute_to_class method within class decorators before ORM schema initialization.

snippet.py

python

from django.db import models
 
def add_audit_timestamp_fields(cls):
    created_field = models.DateTimeField(auto_now_add=True)
    updated_field = models.DateTimeField(auto_now=True)
    
    created_field.contribute_to_class(cls, 'created_at')
    updated_field.contribute_to_class(cls, 'updated_at')
    return cls
 
@add_audit_timestamp_fields
class AuditLogEntry(models.Model):
    action = models.CharField(max_length=255)
    
    class Meta:
        app_label = 'analytics'

django

Breakdown

def add_audit_timestamp_fields(cls):

Defines a class decorator that takes a target Django Model class as input.

created_field.contribute_to_class(cls, 'created_at')

Calls Django's internal field lifecycle API to inject and register model fields dynamically.

@add_audit_timestamp_fields

Applies field injection during module load time before Django model setup completes.

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Dynamic Model Field Injection via Metaclass Class Decorators

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