[permission] Rewrite with comments

This commit is contained in:
Benjamin Graillot 2020-02-09 17:35:15 +01:00
parent 3766a1905d
commit 94c3a99447
1 changed files with 55 additions and 32 deletions

View File

@ -1,4 +1,6 @@
import functools
import json
import operator
from django.contrib.contenttypes.models import ContentType
from django.core.exceptions import ValidationError
@ -9,15 +11,19 @@ from django.utils.translation import gettext_lazy as _
class InstancedPermission:
def __init__(self, model, permission, type, field):
def __init__(self, model, query, type, field):
self.model = model
self.permission = permission
self.query = query
self.type = type
self.field = field
def applies(self, obj, permission_type, field_name=None):
"""
Returns True if the permission applies to
the field `field_name` object `obj`
"""
if ContentType.objects.get_for_model(obj) != self.model:
# The permission does not apply to the object
# The permission does not apply to the model
return False
if self.permission is None:
if permission_type == self.type:
@ -27,21 +33,9 @@ class InstancedPermission:
return True
else:
return False
elif isinstance(self.permission, dict):
for field in self.permission:
value = getattr(obj, field)
if isinstance(value, models.Model):
value = value.pk
if value != self.permission[field]:
return False
elif isinstance(self.permission, type(obj.pk)):
if obj.pk != self.permission:
return False
if permission_type == self.type:
if field_name:
return field_name == self.field
else:
elif obj in self.model.objects.get(self.query):
return True
else:
return False
def __repr__(self):
@ -62,11 +56,24 @@ class Permission(models.Model):
model = models.ForeignKey(ContentType, on_delete=models.CASCADE, related_name='+')
# A json encoded Q object with the following grammar
# permission -> [] | {} (the empty permission representing all objects)
# permission -> ['AND', permission, …]
# -> ['OR', permission, …]
# -> ['NOT', permission]
# permission -> {key: value, …}
# key -> string
# value -> int | string | bool | null
# -> [parameter]
#
# Examples:
# Q(is_admin=True) := {'is_admin': ['TYPE', 'bool', 'True']}
# ~Q(is_admin=True) := ['NOT', {'is_admin': ['TYPE', 'bool', 'True']}]
permission = models.TextField()
type = models.CharField(max_length=15, choices=PERMISSION_TYPES)
type = models.CharField(max_length=16, choices=PERMISSION_TYPES)
field = models.CharField(max_length=255, blank=True)
field = models.CharField(max_length=256, blank=True)
class Meta:
unique_together = ('model', 'permission', 'type', 'field')
@ -80,22 +87,38 @@ class Permission(models.Model):
super().save()
def _about(_self, _permission, **kwargs):
if _permission[0] == 'all':
self = _self
permission = _permission
if len(permission) == 0:
# The permission is either [] or {} and
# applies to all objects of the model
# to represent this we return None
return None
elif _permission[0] == 'pk':
if _permission[1] in kwargs:
return kwargs[_permission[1]].pk
if isinstance(permission, list):
if permission[0] == 'AND':
return functools.reduce(operator.and_, [self._about(permission, **kwargs) for permission in permission[1:]])
elif permission[0] == 'OR':
return functools.reduce(operator.or_, [self._about(permission, **kwargs) for permission in permission[1:]])
elif permission[0] == 'NOT':
return ~self._about(permission[1], **kwargs)
elif isinstance(permission, dict):
q_kwargs = {}
for key in permission:
value = permission[key]
if isinstance(value, list):
# It is a parameter we query its primary key
q_kwargs[key] = kwargs[value[0]].pk
else:
return None
elif _permission[0] == 'filter':
return {field: _self._about(_permission[1][field], **kwargs) for field in _permission[1]}
q_kwargs[key] = value
return Q(**q_kwargs)
else:
return _permission
# TODO: find a better way to crash here
raise Exception("Permission {} is wrong".format(self.permission))
def about(self, **kwargs):
permission = json.loads(self.permission)
permission = self._about(permission, **kwargs)
return InstancedPermission(self.model, permission, self.type, self.field)
query = self._about(permission, **kwargs)
return InstancedPermission(self.model, query, self.type, self.field)
def __str__(self):
if self.field: