import random import string from django.db import models class MyWrapper: def __init__(self, value): self.value = value def __repr__(self): return "<%s: %s>" % (self.__class__.__name__, self.value) def __str__(self): return self.value def __eq__(self, other): if isinstance(other, self.__class__): return self.value == other.value return self.value == other class MyAutoField(models.CharField): def __init__(self, *args, **kwargs): kwargs['max_length'] = 10 super(MyAutoField, self).__init__(*args, **kwargs) def pre_save(self, instance, add): value = getattr(instance, self.attname, None) if not value: value = MyWrapper(''.join(random.sample(string.ascii_lowercase, 10))) setattr(instance, self.attname, value) return value def to_python(self, value): if not value: return if not isinstance(value, MyWrapper): value = MyWrapper(value) return value def from_db_value(self, value, expression, connection, context): if not value: return return MyWrapper(value) def get_db_prep_save(self, value, connection): if not value: return if isinstance(value, MyWrapper): return str(value) return value def get_db_prep_value(self, value, connection, prepared=False): if not value: return if isinstance(value, MyWrapper): return str(value) return value