560 lines
18 KiB
Python
560 lines
18 KiB
Python
# Copyright 2014 Google Inc. All rights reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Manipulate access control lists that Cloud Storage provides.
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:class:`gcloud.storage.bucket.Bucket` has a getting method that creates
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an ACL object under the hood, and you can interact with that using
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:func:`gcloud.storage.bucket.Bucket.acl`::
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>>> from gcloud import storage
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>>> client = storage.Client()
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>>> bucket = client.get_bucket(bucket_name)
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>>> acl = bucket.acl
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Adding and removing permissions can be done with the following methods
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(in increasing order of granularity):
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- :func:`ACL.all`
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corresponds to access for all users.
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- :func:`ACL.all_authenticated` corresponds
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to access for all users that are signed into a Google account.
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- :func:`ACL.domain` corresponds to access on a
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per Google Apps domain (ie, ``example.com``).
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- :func:`ACL.group` corresponds to access on a
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per group basis (either by ID or e-mail address).
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- :func:`ACL.user` corresponds to access on a
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per user basis (either by ID or e-mail address).
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And you are able to ``grant`` and ``revoke`` the following roles:
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- **Reading**:
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:func:`_ACLEntity.grant_read` and :func:`_ACLEntity.revoke_read`
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- **Writing**:
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:func:`_ACLEntity.grant_write` and :func:`_ACLEntity.revoke_write`
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- **Owning**:
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:func:`_ACLEntity.grant_owner` and :func:`_ACLEntity.revoke_owner`
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You can use any of these like any other factory method (these happen to
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be :class:`_ACLEntity` factories)::
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>>> acl.user('me@example.org').grant_read()
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>>> acl.all_authenticated().grant_write()
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You can also chain these ``grant_*`` and ``revoke_*`` methods together
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for brevity::
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>>> acl.all().grant_read().revoke_write()
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After that, you can save any changes you make with the
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:func:`gcloud.storage.acl.ACL.save` method::
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>>> acl.save()
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You can alternatively save any existing :class:`gcloud.storage.acl.ACL`
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object (whether it was created by a factory method or not) from a
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:class:`gcloud.storage.bucket.Bucket`::
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>>> bucket.acl.save(acl=acl)
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To get the list of ``entity`` and ``role`` for each unique pair, the
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:class:`ACL` class is iterable::
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>>> print list(ACL)
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[{'role': 'OWNER', 'entity': 'allUsers'}, ...]
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This list of tuples can be used as the ``entity`` and ``role`` fields
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when sending metadata for ACLs to the API.
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"""
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class _ACLEntity(object):
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"""Class representing a set of roles for an entity.
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This is a helper class that you likely won't ever construct
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outside of using the factor methods on the :class:`ACL` object.
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:type entity_type: string
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:param entity_type: The type of entity (ie, 'group' or 'user').
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:type identifier: string
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:param identifier: The ID or e-mail of the entity. For the special
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entity types (like 'allUsers') this is optional.
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"""
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READER_ROLE = 'READER'
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WRITER_ROLE = 'WRITER'
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OWNER_ROLE = 'OWNER'
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def __init__(self, entity_type, identifier=None):
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self.identifier = identifier
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self.roles = set([])
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self.type = entity_type
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def __str__(self):
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if not self.identifier:
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return str(self.type)
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else:
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return '{acl.type}-{acl.identifier}'.format(acl=self)
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def __repr__(self):
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return '<ACL Entity: {acl} ({roles})>'.format(
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acl=self, roles=', '.join(self.roles))
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def get_roles(self):
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"""Get the list of roles permitted by this entity.
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:rtype: list of strings
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:returns: The list of roles associated with this entity.
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"""
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return self.roles
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def grant(self, role):
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"""Add a role to the entity.
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:type role: string
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:param role: The role to add to the entity.
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"""
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self.roles.add(role)
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def revoke(self, role):
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"""Remove a role from the entity.
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:type role: string
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:param role: The role to remove from the entity.
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"""
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if role in self.roles:
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self.roles.remove(role)
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def grant_read(self):
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"""Grant read access to the current entity."""
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self.grant(_ACLEntity.READER_ROLE)
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def grant_write(self):
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"""Grant write access to the current entity."""
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self.grant(_ACLEntity.WRITER_ROLE)
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def grant_owner(self):
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"""Grant owner access to the current entity."""
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self.grant(_ACLEntity.OWNER_ROLE)
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def revoke_read(self):
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"""Revoke read access from the current entity."""
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self.revoke(_ACLEntity.READER_ROLE)
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def revoke_write(self):
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"""Revoke write access from the current entity."""
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self.revoke(_ACLEntity.WRITER_ROLE)
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def revoke_owner(self):
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"""Revoke owner access from the current entity."""
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self.revoke(_ACLEntity.OWNER_ROLE)
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class ACL(object):
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"""Container class representing a list of access controls."""
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_URL_PATH_ELEM = 'acl'
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_PREDEFINED_QUERY_PARAM = 'predefinedAcl'
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PREDEFINED_XML_ACLS = {
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# XML API name -> JSON API name
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'project-private': 'projectPrivate',
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'public-read': 'publicRead',
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'public-read-write': 'publicReadWrite',
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'authenticated-read': 'authenticatedRead',
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'bucket-owner-read': 'bucketOwnerRead',
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'bucket-owner-full-control': 'bucketOwnerFullControl',
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}
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PREDEFINED_JSON_ACLS = frozenset([
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'private',
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'projectPrivate',
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'publicRead',
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'publicReadWrite',
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'authenticatedRead',
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'bucketOwnerRead',
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'bucketOwnerFullControl',
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])
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"""See:
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https://cloud.google.com/storage/docs/access-control#predefined-acl
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"""
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loaded = False
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# Subclasses must override to provide these attributes (typically,
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# as properties).
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reload_path = None
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save_path = None
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def __init__(self):
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self.entities = {}
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def _ensure_loaded(self):
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"""Load if not already loaded."""
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if not self.loaded:
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self.reload()
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def reset(self):
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"""Remove all entities from the ACL, and clear the ``loaded`` flag."""
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self.entities.clear()
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self.loaded = False
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def __iter__(self):
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self._ensure_loaded()
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for entity in self.entities.values():
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for role in entity.get_roles():
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if role:
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yield {'entity': str(entity), 'role': role}
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def entity_from_dict(self, entity_dict):
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"""Build an _ACLEntity object from a dictionary of data.
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An entity is a mutable object that represents a list of roles
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belonging to either a user or group or the special types for all
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users and all authenticated users.
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:type entity_dict: dict
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:param entity_dict: Dictionary full of data from an ACL lookup.
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:rtype: :class:`_ACLEntity`
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:returns: An Entity constructed from the dictionary.
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"""
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entity = entity_dict['entity']
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role = entity_dict['role']
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if entity == 'allUsers':
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entity = self.all()
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elif entity == 'allAuthenticatedUsers':
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entity = self.all_authenticated()
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elif '-' in entity:
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entity_type, identifier = entity.split('-', 1)
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entity = self.entity(entity_type=entity_type,
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identifier=identifier)
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if not isinstance(entity, _ACLEntity):
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raise ValueError('Invalid dictionary: %s' % entity_dict)
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entity.grant(role)
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return entity
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def has_entity(self, entity):
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"""Returns whether or not this ACL has any entries for an entity.
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:type entity: :class:`_ACLEntity`
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:param entity: The entity to check for existence in this ACL.
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:rtype: boolean
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:returns: True of the entity exists in the ACL.
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"""
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self._ensure_loaded()
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return str(entity) in self.entities
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def get_entity(self, entity, default=None):
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"""Gets an entity object from the ACL.
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:type entity: :class:`_ACLEntity` or string
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:param entity: The entity to get lookup in the ACL.
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:type default: anything
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:param default: This value will be returned if the entity
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doesn't exist.
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:rtype: :class:`_ACLEntity`
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:returns: The corresponding entity or the value provided
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to ``default``.
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"""
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self._ensure_loaded()
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return self.entities.get(str(entity), default)
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def add_entity(self, entity):
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"""Add an entity to the ACL.
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:type entity: :class:`_ACLEntity`
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:param entity: The entity to add to this ACL.
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"""
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self._ensure_loaded()
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self.entities[str(entity)] = entity
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def entity(self, entity_type, identifier=None):
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"""Factory method for creating an Entity.
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If an entity with the same type and identifier already exists,
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this will return a reference to that entity. If not, it will
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create a new one and add it to the list of known entities for
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this ACL.
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:type entity_type: string
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:param entity_type: The type of entity to create
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(ie, ``user``, ``group``, etc)
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:type identifier: string
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:param identifier: The ID of the entity (if applicable).
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This can be either an ID or an e-mail address.
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:rtype: :class:`_ACLEntity`
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:returns: A new Entity or a reference to an existing identical entity.
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"""
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entity = _ACLEntity(entity_type=entity_type, identifier=identifier)
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if self.has_entity(entity):
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entity = self.get_entity(entity)
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else:
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self.add_entity(entity)
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return entity
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def user(self, identifier):
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"""Factory method for a user Entity.
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:type identifier: string
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:param identifier: An id or e-mail for this particular user.
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:rtype: :class:`_ACLEntity`
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:returns: An Entity corresponding to this user.
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"""
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return self.entity('user', identifier=identifier)
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def group(self, identifier):
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"""Factory method for a group Entity.
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:type identifier: string
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:param identifier: An id or e-mail for this particular group.
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:rtype: :class:`_ACLEntity`
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:returns: An Entity corresponding to this group.
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"""
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return self.entity('group', identifier=identifier)
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def domain(self, domain):
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"""Factory method for a domain Entity.
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:type domain: string
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:param domain: The domain for this entity.
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:rtype: :class:`_ACLEntity`
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:returns: An entity corresponding to this domain.
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"""
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return self.entity('domain', identifier=domain)
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def all(self):
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"""Factory method for an Entity representing all users.
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:rtype: :class:`_ACLEntity`
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:returns: An entity representing all users.
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"""
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return self.entity('allUsers')
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def all_authenticated(self):
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"""Factory method for an Entity representing all authenticated users.
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:rtype: :class:`_ACLEntity`
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:returns: An entity representing all authenticated users.
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"""
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return self.entity('allAuthenticatedUsers')
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def get_entities(self):
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"""Get a list of all Entity objects.
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:rtype: list of :class:`_ACLEntity` objects
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:returns: A list of all Entity objects.
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"""
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self._ensure_loaded()
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return list(self.entities.values())
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@property
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def client(self):
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"""Abstract getter for the object client."""
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raise NotImplementedError
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def _require_client(self, client):
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"""Check client or verify over-ride.
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:type client: :class:`gcloud.storage.client.Client` or ``NoneType``
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:param client: the client to use. If not passed, falls back to the
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``client`` stored on the current ACL.
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:rtype: :class:`gcloud.storage.client.Client`
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:returns: The client passed in or the currently bound client.
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"""
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if client is None:
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client = self.client
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return client
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def reload(self, client=None):
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"""Reload the ACL data from Cloud Storage.
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:type client: :class:`gcloud.storage.client.Client` or ``NoneType``
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:param client: Optional. The client to use. If not passed, falls back
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to the ``client`` stored on the ACL's parent.
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"""
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path = self.reload_path
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client = self._require_client(client)
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self.entities.clear()
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found = client.connection.api_request(method='GET', path=path)
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self.loaded = True
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for entry in found.get('items', ()):
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self.add_entity(self.entity_from_dict(entry))
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def _save(self, acl, predefined, client):
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"""Helper for :meth:`save` and :meth:`save_predefined`.
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:type acl: :class:`gcloud.storage.acl.ACL`, or a compatible list.
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:param acl: The ACL object to save. If left blank, this will save
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current entries.
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:type predefined: string or None
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:param predefined: An identifier for a predefined ACL. Must be one
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of the keys in :attr:`PREDEFINED_JSON_ACLS`
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If passed, `acl` must be None.
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:type client: :class:`gcloud.storage.client.Client` or ``NoneType``
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:param client: Optional. The client to use. If not passed, falls back
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to the ``client`` stored on the ACL's parent.
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"""
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query_params = {'projection': 'full'}
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if predefined is not None:
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acl = []
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query_params[self._PREDEFINED_QUERY_PARAM] = predefined
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path = self.save_path
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client = self._require_client(client)
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result = client.connection.api_request(
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method='PATCH',
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path=path,
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data={self._URL_PATH_ELEM: list(acl)},
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query_params=query_params)
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self.entities.clear()
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for entry in result.get(self._URL_PATH_ELEM, ()):
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self.add_entity(self.entity_from_dict(entry))
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self.loaded = True
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def save(self, acl=None, client=None):
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"""Save this ACL for the current bucket.
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:type acl: :class:`gcloud.storage.acl.ACL`, or a compatible list.
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:param acl: The ACL object to save. If left blank, this will save
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current entries.
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:type client: :class:`gcloud.storage.client.Client` or ``NoneType``
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:param client: Optional. The client to use. If not passed, falls back
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to the ``client`` stored on the ACL's parent.
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"""
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if acl is None:
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acl = self
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save_to_backend = acl.loaded
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else:
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save_to_backend = True
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if save_to_backend:
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self._save(acl, None, client)
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def save_predefined(self, predefined, client=None):
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"""Save this ACL for the current bucket using a predefined ACL.
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:type predefined: string
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:param predefined: An identifier for a predefined ACL. Must be one
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of the keys in :attr:`PREDEFINED_JSON_ACLS`
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or :attr:`PREDEFINED_XML_ACLS` (which will be
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aliased to the corresponding JSON name).
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If passed, `acl` must be None.
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:type client: :class:`gcloud.storage.client.Client` or ``NoneType``
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:param client: Optional. The client to use. If not passed, falls back
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to the ``client`` stored on the ACL's parent.
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"""
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predefined = self.PREDEFINED_XML_ACLS.get(predefined, predefined)
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if predefined not in self.PREDEFINED_JSON_ACLS:
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raise ValueError("Invalid predefined ACL: %s" % (predefined,))
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self._save(None, predefined, client)
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def clear(self, client=None):
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"""Remove all ACL entries.
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Note that this won't actually remove *ALL* the rules, but it
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will remove all the non-default rules. In short, you'll still
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have access to a bucket that you created even after you clear
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ACL rules with this method.
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:type client: :class:`gcloud.storage.client.Client` or ``NoneType``
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:param client: Optional. The client to use. If not passed, falls back
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to the ``client`` stored on the ACL's parent.
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"""
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self.save([], client=client)
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class BucketACL(ACL):
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"""An ACL specifically for a bucket.
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:type bucket: :class:`gcloud.storage.bucket.Bucket`
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:param bucket: The bucket to which this ACL relates.
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"""
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def __init__(self, bucket):
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super(BucketACL, self).__init__()
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self.bucket = bucket
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@property
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def client(self):
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"""The client bound to this ACL's bucket."""
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return self.bucket.client
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@property
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def reload_path(self):
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"""Compute the path for GET API requests for this ACL."""
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return '%s/%s' % (self.bucket.path, self._URL_PATH_ELEM)
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@property
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def save_path(self):
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"""Compute the path for PATCH API requests for this ACL."""
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return self.bucket.path
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class DefaultObjectACL(BucketACL):
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"""A class representing the default object ACL for a bucket."""
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_URL_PATH_ELEM = 'defaultObjectAcl'
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_PREDEFINED_QUERY_PARAM = 'predefinedDefaultObjectAcl'
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class ObjectACL(ACL):
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"""An ACL specifically for a Cloud Storage object / blob.
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:type blob: :class:`gcloud.storage.blob.Blob`
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:param blob: The blob that this ACL corresponds to.
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"""
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def __init__(self, blob):
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super(ObjectACL, self).__init__()
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self.blob = blob
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@property
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def client(self):
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"""The client bound to this ACL's blob."""
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return self.blob.client
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@property
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def reload_path(self):
|
|
"""Compute the path for GET API requests for this ACL."""
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|
return '%s/acl' % self.blob.path
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|
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@property
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def save_path(self):
|
|
"""Compute the path for PATCH API requests for this ACL."""
|
|
return self.blob.path
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