Synnefo

We need Read, Write and ModifyACL permissions that can apply to either a user or a group. Permissions need to be hierarchical: permissions of the parent apply to all the children too (unless overridden).

Since we have a pseudo-hierarchy we will probably have to use a prefix based inheritance ("photo" is a parent of "photos"). A possible interface could be something like the following:

def set_permission(path, user_or_group, read=False, write=False, modify=False):
    return

def delete_permission(path, user_or_group):
    return

def get_permissions(path):
    """Returns a list of tuples (USER_OR_GROUP, READ, WRITE, MODIFY, LOCAL).
    LOCAL is a boolean value to differentiate between permissions that have been set for this path
    and permissions that apply due to inheritance.
    """ 
    return []

def check_permission(path, user_or_group, perm):
    """`perm` can be one of "read", "write" and "modify".
    This method will check `path` and all its parents and decide if `user_or_group` is allowed to perform `perm`.
    """ 
    return False

This module will be used by the backends.