145 lines
5.4 KiB
Python
145 lines
5.4 KiB
Python
from typing import TYPE_CHECKING, Any, Dict, List, Optional
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from django.core.exceptions import ImproperlyConfigured
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from django.db import models
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from .access_permissions import BaseAccessPermissions
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from .utils import convert_camel_case_to_pseudo_snake_case
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if TYPE_CHECKING:
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# Dummy import Collection for mypy, can be fixed with python 3.7
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from .collection import CollectionElement # noqa
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class MinMaxIntegerField(models.IntegerField):
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"""
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IntegerField with options to set a min- and a max-value.
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"""
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def __init__(self, min_value: int = None, max_value: int = None, *args: Any, **kwargs: Any) -> None:
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self.min_value, self.max_value = min_value, max_value
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super(MinMaxIntegerField, self).__init__(*args, **kwargs)
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def formfield(self, **kwargs: Any) -> Any:
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defaults = {'min_value': self.min_value, 'max_value': self.max_value}
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defaults.update(kwargs)
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return super(MinMaxIntegerField, self).formfield(**defaults)
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class RESTModelMixin:
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"""
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Mixin for Django models which are used in our REST API.
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"""
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access_permissions: Optional[BaseAccessPermissions] = None
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def get_root_rest_element(self) -> models.Model:
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"""
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Returns the root rest instance.
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Uses self as default.
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"""
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return self
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@classmethod
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def get_access_permissions(cls) -> BaseAccessPermissions:
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"""
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Returns a container to handle access permissions for this model and
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its corresponding viewset.
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"""
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if cls.access_permissions is None:
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raise ImproperlyConfigured("A RESTModel needs to have an access_permission.")
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return cls.access_permissions
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@classmethod
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def get_collection_string(cls) -> str:
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"""
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Returns the string representing the name of the collection. Returns
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None if this is not a so called root rest instance.
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"""
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# TODO Check if this is a root rest element class and return None if not.
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app_label = cls._meta.app_label # type: ignore
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object_name = cls._meta.object_name # type: ignore
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return '/'.join(
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(convert_camel_case_to_pseudo_snake_case(app_label),
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convert_camel_case_to_pseudo_snake_case(object_name)))
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def get_rest_pk(self) -> int:
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"""
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Returns the primary key used in the REST API. By default this is
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the database pk.
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"""
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return self.pk # type: ignore
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def save(self, skip_autoupdate: bool = False, *args: Any, **kwargs: Any) -> Any:
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"""
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Calls Django's save() method and afterwards hits the autoupdate system.
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If skip_autoupdate is set to True, then the autoupdate system is not
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informed about the model changed. This also means, that the model cache
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is not updated. You have to do this manually, by creating a collection
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element from the instance:
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CollectionElement.from_instance(instance)
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"""
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# We don't know how to fix this circular import
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from .autoupdate import inform_changed_data
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return_value = super().save(*args, **kwargs) # type: ignore
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if not skip_autoupdate:
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inform_changed_data(self.get_root_rest_element())
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return return_value
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def delete(self, skip_autoupdate: bool = False, *args: Any, **kwargs: Any) -> Any:
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"""
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Calls Django's delete() method and afterwards hits the autoupdate system.
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If skip_autoupdate is set to True, then the autoupdate system is not
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informed about the model changed. This also means, that the model cache
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is not updated. You have to do this manually, by creating a collection
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element from the instance:
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CollectionElement.from_instance(instance, deleted=True)
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or
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CollectionElement.from_values(collection_string, id, deleted=True)
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"""
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# We don't know how to fix this circular import
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from .autoupdate import inform_changed_data, inform_deleted_data
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instance_pk = self.pk # type: ignore
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return_value = super().delete(*args, **kwargs) # type: ignore
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if not skip_autoupdate:
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if self != self.get_root_rest_element():
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# The deletion of a included element is a change of the root element.
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inform_changed_data(self.get_root_rest_element())
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else:
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inform_deleted_data([(self.get_collection_string(), instance_pk)])
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return return_value
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@classmethod
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def get_elements(cls) -> List[Dict[str, Any]]:
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"""
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Returns all elements as full_data.
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"""
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# Get the query to receive all data from the database.
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try:
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query = cls.objects.get_full_queryset() # type: ignore
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except AttributeError:
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# If the model des not have to method get_full_queryset(), then use
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# the default queryset from django.
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query = cls.objects # type: ignore
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# Build a dict from the instance id to the full_data
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return [cls.get_access_permissions().get_full_data(instance) for instance in query.all()]
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@classmethod
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def restrict_elements(
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cls,
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user: Optional['CollectionElement'],
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elements: List[Dict[str, Any]]) -> List[Dict[str, Any]]:
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"""
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Converts a list of elements from full_data to restricted_data.
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"""
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return cls.get_access_permissions().get_restricted_data(elements, user)
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