| 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) |
|
|
