OpenSlides/openslides/utils/models.py
2017-09-03 18:34:55 +02:00

120 lines
4.6 KiB
Python

from typing import Any, Dict
from django.core.exceptions import ImproperlyConfigured
from django.db import models
from .access_permissions import BaseAccessPermissions # noqa
from .utils import convert_camel_case_to_pseudo_snake_case
class MinMaxIntegerField(models.IntegerField):
"""
IntegerField with options to set a min- and a max-value.
"""
def __init__(self, min_value: int=None, max_value: int=None, *args: Any, **kwargs: Any) -> None:
self.min_value, self.max_value = min_value, max_value
super(MinMaxIntegerField, self).__init__(*args, **kwargs)
def formfield(self, **kwargs: Any) -> Any:
defaults = {'min_value': self.min_value, 'max_value': self.max_value}
defaults.update(kwargs)
return super(MinMaxIntegerField, self).formfield(**defaults)
class RESTModelMixin:
"""
Mixin for Django models which are used in our REST API.
"""
access_permissions = None # type: BaseAccessPermissions
def get_root_rest_element(self) -> models.Model:
"""
Returns the root rest instance.
Uses self as default.
"""
return self
@classmethod
def get_access_permissions(cls) -> BaseAccessPermissions:
"""
Returns a container to handle access permissions for this model and
its corresponding viewset.
"""
if cls.access_permissions is None:
raise ImproperlyConfigured("A RESTModel needs to have an access_permission.")
return cls.access_permissions
@classmethod
def get_collection_string(cls) -> str:
"""
Returns the string representing the name of the collection. Returns
None if this is not a so called root rest instance.
"""
# TODO Check if this is a root rest element class and return None if not.
app_label = cls._meta.app_label # type: ignore
object_name = cls._meta.object_name # type: ignore
return '/'.join(
(convert_camel_case_to_pseudo_snake_case(app_label),
convert_camel_case_to_pseudo_snake_case(object_name)))
def get_rest_pk(self) -> int:
"""
Returns the primary key used in the REST API. By default this is
the database pk.
"""
return self.pk # type: ignore
def save(self, skip_autoupdate: bool=False, information: Dict[str, str]=None, *args: Any, **kwargs: Any) -> Any:
"""
Calls Django's save() method and afterwards hits the autoupdate system.
If skip_autoupdate is set to True, then the autoupdate system is not
informed about the model changed. This also means, that the model cache
is not updated. You have to do this manually, by creating a collection
element from the instance:
CollectionElement.from_instance(instance)
The optional argument information can be a dictionary that is given to
the autoupdate system.
"""
# We don't know how to fix this circular import
from .autoupdate import inform_changed_data
return_value = super().save(*args, **kwargs) # type: ignore
if not skip_autoupdate:
inform_changed_data(self.get_root_rest_element(), information=information)
return return_value
def delete(self, skip_autoupdate: bool=False, information: Dict[str, str]=None, *args: Any, **kwargs: Any) -> Any:
"""
Calls Django's delete() method and afterwards hits the autoupdate system.
If skip_autoupdate is set to True, then the autoupdate system is not
informed about the model changed. This also means, that the model cache
is not updated. You have to do this manually, by creating a collection
element from the instance:
CollectionElement.from_instance(instance, deleted=True)
or
CollectionElement.from_values(collection_string, id, deleted=True)
The optional argument information can be a dictionary that is given to
the autoupdate system.
"""
# We don't know how to fix this circular import
from .autoupdate import inform_changed_data, inform_deleted_data
instance_pk = self.pk # type: ignore
return_value = super().delete(*args, **kwargs) # type: ignore
if not skip_autoupdate:
if self != self.get_root_rest_element():
# The deletion of a included element is a change of the root element.
inform_changed_data(self.get_root_rest_element(), information=information)
else:
inform_deleted_data(self.get_collection_string(), instance_pk, information=information)
return return_value