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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 MyWrapperField(models.CharField):
def __init__(self, *args, **kwargs):
kwargs["max_length"] = 10
super().__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):
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
class MyAutoField(models.BigAutoField):
def from_db_value(self, value, expression, connection):
if value is None:
return None
return MyWrapper(value)
def get_prep_value(self, value):
if value is None:
return None
return int(value)
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