from django.db import models
from django import forms
from django.core import exceptions
import math
class PositiveBigIntegerField(models.BigIntegerField):
description = "Positive Big integer"
def formfield(self, **kwargs):
defaults = {'min_value': 0,
'max_value': models.BigIntegerField.MAX_BIGINT * 2 - 1}
defaults.update(kwargs)
return super(PositiveBigIntegerField, self).formfield(**defaults)
def db_type(self, connection):
if 'mysql' in connection.__class__.__module__:
return 'bigint UNSIGNED'
return super(PositiveBigIntegerField, self).db_type(connection)
class PositiveBigAutoField(models.AutoField):
description = "Unsigned Big Integer"
empty_strings_allowed = False
MAX_BIGINT = 9223372036854775807
def db_type(self, connection):
if 'mysql' in connection.__class__.__module__:
return 'bigint UNSIGNED AUTO_INCREMENT'
return super(PositiveBigAutoField, self).db_type(connection)
default_error_messages = {
'invalid': "'%(value)s' value must be an integer.",
}
def get_prep_value(self, value):
if value is None:
return None
return int(value)
def get_prep_lookup(self, lookup_type, value):
if ((lookup_type == 'gte' or lookup_type == 'lt')
and isinstance(value, float)):
value = math.ceil(value)
return super(PositiveBigAutoField, self).get_prep_lookup(lookup_type, value)
def to_python(self, value):
if value is None:
return value
try:
return int(value)
except (TypeError, ValueError):
raise exceptions.ValidationError(
self.error_messages['invalid'],
code='invalid',
params={'value': value},
)
def formfield(self, **kwargs):
defaults = {'min_value': 0,
'max_value': PositiveBigAutoField.MAX_BIGINT * 2 - 1,
'form_class': forms.IntegerField }
defaults.update(kwargs)
return super(PositiveBigAutoField, self).formfield(**defaults)
class PositiveBigAutoForeignKey(models.ForeignKey):
"""A special foriegn key field for positive big auto fields"""
def db_type(self, connection):
# The database column type of a ForeignKey is the column type
# of the field to which it points. An exception is if the ForeignKey
# points to an AutoField/PositiveIntegerField/PositiveSmallIntegerField,
# in which case the column type is simply that of an IntegerField.
# If the database needs similar types for key fields however, the only
# thing we can do is making AutoField an IntegerField.
rel_field = self.related_field
if isinstance(rel_field, PositiveBigAutoField):
return PositiveBigIntegerField().db_type(connection=connection)
return rel_field.db_type(connection=connection)
try:
# If we are using south, we need some rules to use these fields
from south.modelsinspector import add_introspection_rules
add_introspection_rules([], ["^twitter_stream\.fields\.PositiveBigAutoField"])
add_introspection_rules([], ["^twitter_stream\.fields\.PositiveBigIntegerField"])
add_introspection_rules([], ["^twitter_stream\.fields\.PositiveBigAutoForeignKey"])
except ImportError:
pass
