Synnefo

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class BaseBackend(object):

    """Abstract backend class that serves as a reference for actual implementations.

    The purpose of the backend is to provide the necessary functions for handling data

    and metadata. It is responsible for the actual storage and retrieval of information.

    Note that the account level is always valid as it is checked from another subsystem.

    When not replacing metadata, keys with empty values should be deleted.

    The following variables should be available:

        'hash_algorithm': Suggested is 'sha256'

        'block_size': Suggested is 4MB

    """

    def delete_account(self, user, account):

        """Delete the account with the given name.

        Raises:

            IndexError: Account is not empty

        """

        return

    def get_account_meta(self, user, account, until=None):

        """Return a dictionary with the account metadata.

        The keys returned are all user-defined, except:

            'name': The account name

            'count': The number of containers (or 0)

            'bytes': The total data size (or 0)

            'modified': Last modification timestamp (overall)

            'until_timestamp': Last modification until the timestamp provided

        """

        return {}

    def update_account_meta(self, user, account, meta, replace=False):

        """Update the metadata associated with the account.

        Parameters:

            'meta': Dictionary with metadata to update

            'replace': Replace instead of update

        """

        return

    def list_containers(self, user, account, marker=None, limit=10000, until=None):

        """Return a list of container (name, version_id) tuples existing under an account.

        Parameters:

            'marker': Start list from the next item after 'marker'

            'limit': Number of containers to return

        """

        return []

    def put_container(self, user, account, container):

        """Create a new container with the given name.

        Raises:

            NameError: Container already exists

        """

        return

    def delete_container(self, user, account, container):

        """Delete the container with the given name.

        Raises:

            NameError: Container does not exist

            IndexError: Container is not empty

        """

        return

    def get_container_meta(self, user, account, container, until=None):

        """Return a dictionary with the container metadata.

        The keys returned are all user-defined, except:

            'name': The container name

            'count': The number of objects

            'bytes': The total data size

            'modified': Last modification timestamp (overall)

            'until_timestamp': Last modification until the timestamp provided

        Raises:

            NameError: Container does not exist

        """

        return {}

    def update_container_meta(self, user, account, container, meta, replace=False):

        """Update the metadata associated with the container.

        Parameters:

            'meta': Dictionary with metadata to update

            'replace': Replace instead of update

        Raises:

            NameError: Container does not exist

        """

        return

    def list_objects(self, user, account, container, prefix='', delimiter=None, marker=None, limit=10000, virtual=True, keys=[], until=None):

        """Return a list of object (name, version_id) tuples existing under a container.

        Parameters:

            'prefix': List objects starting with 'prefix'

            'delimiter': Return unique names before 'delimiter' and after 'prefix'

            'marker': Start list from the next item after 'marker'

            'limit': Number of objects to return

            'virtual': If not set, the result will only include names starting\

                       with 'prefix' and ending without a 'delimiter' or with\

                       the first occurance of the 'delimiter' after 'prefix'.\

                       If set, the result will include all names after 'prefix',\

                       up to and including the 'delimiter' if it is found

            'keys': Include objects that have meta with the keys in the list

        Raises:

            NameError: Container does not exist

        """

        return []

    def list_object_meta(self, user, account, container, until=None):

        """Return a list with all the container's object meta keys.

        Raises:

            NameError: Container does not exist

        """

        return []

    def get_object_meta(self, user, account, container, name, version=None):

        """Return a dictionary with the object metadata.

        The keys returned are all user-defined, except:

            'name': The object name

            'bytes': The total data size

            'modified': Last modification timestamp (overall)

            'version': The version identifier

            'version_timestamp': The version's modification timestamp

        Raises:

            NameError: Container/object does not exist

            IndexError: Version does not exist

        """

        return {}

    def update_object_meta(self, user, account, container, name, meta, replace=False):

        """Update the metadata associated with the object.

        Parameters:

            'meta': Dictionary with metadata to update

            'replace': Replace instead of update

        Raises:

            NameError: Container/object does not exist

        """

        return

    def get_object_permissions(self, user, account, container, name):

        """Return a dictionary with the object permissions.

        The keys are:

            'public': The object is readable by all and available at a public URL

            'private': No permissions set

            'read': The object is readable by the users/groups in the list

            'write': The object is writable by the users/groups in the list

        Raises:

            NameError: Container/object does not exist

        """

        return {}

    def update_object_permissions(self, user, account, container, name, permissions):

        """Update the permissions associated with the object.

        Parameters:

            'permissions': Dictionary with permissions to update

        Raises:

            NameError: Container/object does not exist

            ValueError: Invalid users/groups in permissions

            AttributeError: Can not set permissions, as this object\

                is already shared/private by another object higher\

                in the hierarchy, or setting permissions here will\

                invalidate other permissions deeper in the hierarchy

        """

        return

    def get_object_hashmap(self, user, account, container, name, version=None):

        """Return the object's size and a list with partial hashes.

        Raises:

            NameError: Container/object does not exist

            IndexError: Version does not exist

        """

        return 0, []

    def update_object_hashmap(self, user, account, container, name, size, hashmap, meta={}, replace_meta=False, permissions={}):

        """Create/update an object with the specified size and partial hashes.

        Parameters:

            'dest_meta': Dictionary with metadata to change

            'replace_meta': Replace metadata instead of update

            'permissions': Updated object permissions

        Raises:

            NameError: Container does not exist

            ValueError: Invalid users/groups in permissions

            AttributeError: Can not set permissions

        """

        return

    def copy_object(self, user, account, src_container, src_name, dest_container, dest_name, dest_meta={}, replace_meta=False, permissions={}, src_version=None):

        """Copy an object's data and metadata.

        Parameters:

            'dest_meta': Dictionary with metadata to change from source to destination

            'replace_meta': Replace metadata instead of update

            'permissions': New object permissions

            'src_version': Copy from the version provided

        Raises:

            NameError: Container/object does not exist

            IndexError: Version does not exist

            ValueError: Invalid users/groups in permissions

            AttributeError: Can not set permissions

        """

        return

    def move_object(self, user, account, src_container, src_name, dest_container, dest_name, dest_meta={}, replace_meta=False, permissions={}):

        """Move an object's data and metadata.

        Parameters:

            'dest_meta': Dictionary with metadata to change from source to destination

            'replace_meta': Replace metadata instead of update

            'permissions': New object permissions

        Raises:

            NameError: Container/object does not exist

            ValueError: Invalid users/groups in permissions

            AttributeError: Can not set permissions

        """

        return

    def delete_object(self, user, account, container, name):

        """Delete an object.

        Raises:

            NameError: Container/object does not exist

        """

        return

    def list_versions(self, user, account, container, name):

        """Return a list of all (version, version_timestamp) tuples for an object."""

        return []

    def get_block(self, hash):

        """Return a block's data.

        Raises:

            NameError: Block does not exist

        """

        return ''

    def put_block(self, data):

        """Store a block and return the hash."""

        return 0

    def update_block(self, hash, data, offset=0):

        """Update a known block and return the hash.

        Raises:

            IndexError: Offset or data outside block limits

        """

        return 0