mirror of
https://gitlab2.federez.net/re2o/re2o
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290 lines
10 KiB
Python
290 lines
10 KiB
Python
# -*- mode: python; coding: utf-8 -*-
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# Re2o est un logiciel d'administration développé initiallement au rezometz. Il
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# se veut agnostique au réseau considéré, de manière à être installable en
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# quelques clics.
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#
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# Copyright © 2018 Maël Kervella
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License along
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# with this program; if not, write to the Free Software Foundation, Inc.,
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# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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"""Defines the permission classes used in the API.
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"""
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from rest_framework import permissions, exceptions
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from django.http import Http404
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from . import acl
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def can_see_api(*_, **__):
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"""Check if a user can view the API.
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Returns:
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A function that takes a user as an argument and returns
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an ACL tuple that assert this user can see the API.
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"""
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return lambda user: acl.can_view(user)
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def _get_param_in_view(view, param_name):
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"""Utility function to retrieve an attribute in a view passed in argument.
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Uses the result of `{view}.get_{param_name}()` if existing else uses the
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value of `{view}.{param_name}` directly.
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Args:
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view: The view where to look into.
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param_name: The name of the attribute to look for.
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Returns:
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The result of the getter function if found else the value of the
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attribute itself.
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Raises:
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AssertionError: None of the getter function or the attribute are
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defined in the view.
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"""
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assert (
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hasattr(view, "get_" + param_name)
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or getattr(view, param_name, None) is not None
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), (
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"cannot apply {} on a view that does not set "
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"`.{}` or have a `.get_{}()` method."
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).format(
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self.__class__.__name__, param_name, param_name
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)
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if hasattr(view, "get_" + param_name):
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param = getattr(view, "get_" + param_name)()
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assert param is not None, ("{}.get_{}() returned None").format(
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view.__class__.__name__, param_name
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)
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return param
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return getattr(view, param_name)
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class ACLPermission(permissions.BasePermission):
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"""A permission class used to check the ACL to validate the permissions
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of a user.
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The view must define a `.get_perms_map()` or a `.perms_map` attribute.
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See the wiki for the syntax of this attribute.
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"""
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@staticmethod
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def get_required_permissions(method, view):
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"""Build the list of permissions required for the request to be
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accepted.
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Args:
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method: The HTTP method name used for the request.
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view: The view which is responding to the request.
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Returns:
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The list of ACL functions to apply to a user in order to check
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if he has the right permissions.
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Raises:
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AssertionError: None of `.get_perms_map()` or `.perms_map` are
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defined in the view.
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rest_framework.exception.MethodNotAllowed: The requested method
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is not allowed for this view.
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"""
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perms_map = _get_param_in_view(view, "perms_map")
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if method not in perms_map:
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raise exceptions.MethodNotAllowed(method)
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return [can_see_api()] + list(perms_map[method])
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def has_permission(self, request, view):
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"""Check that the user has the permissions to perform the request.
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Args:
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request: The request performed.
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view: The view which is responding to the request.
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Returns:
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A boolean indicating if the user has the permission to
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perform the request.
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Raises:
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AssertionError: None of `.get_perms_map()` or `.perms_map` are
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defined in the view.
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rest_framework.exception.MethodNotAllowed: The requested method
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is not allowed for this view.
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"""
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# Workaround to ensure ACLPermissions are not applied
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# to the root view when using DefaultRouter.
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if getattr(view, "_ignore_model_permissions", False):
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return True
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if not request.user or not request.user.is_authenticated:
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return False
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perms = self.get_required_permissions(request.method, view)
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return all(perm(request.user)[0] for perm in perms)
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class AutodetectACLPermission(permissions.BasePermission):
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"""A permission class used to autodetect the ACL needed to validate the
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permissions of a user based on the queryset of the view.
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The view must define a `.get_queryset()` or a `.queryset` attribute.
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Attributes:
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perms_map: The mapping of each valid HTTP method to the required
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model-based ACL permissions.
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perms_obj_map: The mapping of each valid HTTP method to the required
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object-based ACL permissions.
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"""
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perms_map = {
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"GET": [can_see_api, lambda model: model.can_view_all],
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"OPTIONS": [can_see_api, lambda model: model.can_view_all],
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"HEAD": [can_see_api, lambda model: model.can_view_all],
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"POST": [can_see_api, lambda model: model.can_create],
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"PUT": [], # No restrictions, apply to objects
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"PATCH": [], # No restrictions, apply to objects
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"DELETE": [], # No restrictions, apply to objects
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}
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perms_obj_map = {
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"GET": [can_see_api, lambda obj: obj.can_view],
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"OPTIONS": [can_see_api, lambda obj: obj.can_view],
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"HEAD": [can_see_api, lambda obj: obj.can_view],
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"POST": [], # No restrictions, apply to models
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"PUT": [can_see_api, lambda obj: obj.can_edit],
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"PATCH": [can_see_api, lambda obj: obj.can_edit],
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"DELETE": [can_see_api, lambda obj: obj.can_delete],
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}
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def get_required_permissions(self, method, model):
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"""Build the list of model-based permissions required for the
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request to be accepted.
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Args:
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method: The HTTP method name used for the request.
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view: The view which is responding to the request.
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Returns:
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The list of ACL functions to apply to a user in order to check
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if he has the right permissions.
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Raises:
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rest_framework.exception.MethodNotAllowed: The requested method
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is not allowed for this view.
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"""
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if method not in self.perms_map:
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raise exceptions.MethodNotAllowed(method)
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return [perm(model) for perm in self.perms_map[method]]
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def get_required_object_permissions(self, method, obj):
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"""Build the list of object-based permissions required for the
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request to be accepted.
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Args:
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method: The HTTP method name used for the request.
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view: The view which is responding to the request.
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Returns:
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The list of ACL functions to apply to a user in order to check
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if he has the right permissions.
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Raises:
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rest_framework.exception.MethodNotAllowed: The requested method
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is not allowed for this view.
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"""
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if method not in self.perms_obj_map:
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raise exceptions.MethodNotAllowed(method)
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return [perm(obj) for perm in self.perms_obj_map[method]]
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@staticmethod
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def _queryset(view):
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return _get_param_in_view(view, "queryset")
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def has_permission(self, request, view):
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"""Check that the user has the model-based permissions to perform
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the request.
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Args:
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request: The request performed.
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view: The view which is responding to the request.
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Returns:
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A boolean indicating if the user has the permission to
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perform the request.
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Raises:
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AssertionError: None of `.get_queryset()` or `.queryset` are
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defined in the view.
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rest_framework.exception.MethodNotAllowed: The requested method
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is not allowed for this view.
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"""
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# Workaround to ensure ACLPermissions are not applied
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# to the root view when using DefaultRouter.
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if getattr(view, "_ignore_model_permissions", False):
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return True
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if not request.user or not request.user.is_authenticated:
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return False
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queryset = self._queryset(view)
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perms = self.get_required_permissions(request.method, queryset.model)
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return all(perm(request.user)[0] for perm in perms)
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def has_object_permission(self, request, view, obj):
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"""Check that the user has the object-based permissions to perform
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the request.
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Args:
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request: The request performed.
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view: The view which is responding to the request.
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Returns:
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A boolean indicating if the user has the permission to
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perform the request.
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Raises:
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rest_framework.exception.MethodNotAllowed: The requested method
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is not allowed for this view.
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"""
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# authentication checks have already executed via has_permission
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user = request.user
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perms = self.get_required_object_permissions(request.method, obj)
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if not all(perm(request.user)[0] for perm in perms):
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# If the user does not have permissions we need to determine if
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# they have read permissions to see 403, or not, and simply see
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# a 404 response.
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SAFE_METHODS = ("GET", "OPTIONS", "HEAD", "POST", "PUT", "PATCH", "DELETE")
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if request.method in SAFE_METHODS:
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# Read permissions already checked and failed, no need
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# to make another lookup.
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raise Http404
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read_perms = self.get_required_object_permissions("GET", obj)
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if not read_perms(request.user)[0]:
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raise Http404
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# Has read permissions.
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return False
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return True
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