1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
|
"""
Part of the BlackStar filesystem (bsfs) module.
A copy of the license is provided with the project.
Author: Matthias Baumgartner, 2022
"""
# imports
import abc
import typing
# bsfs imports
from bsfs import schema
from bsfs.query import ast
from bsfs.triple_store import TripleStoreBase
from bsfs.utils import URI
# exports
__all__: typing.Sequence[str] = (
'AccessControlBase',
)
## code ##
class AccessControlBase(abc.ABC):
"""Defines the interface for access control policies.
An access control policy governs which actions a user may take to query
or to manipulate a graph.
"""
# The triple store backend.
_backend: TripleStoreBase
# The current user.
_user: URI
def __init__(
self,
backend: TripleStoreBase,
user: URI,
):
self._backend = backend
self._user = URI(user)
@abc.abstractmethod
def is_protected_predicate(self, pred: schema.Predicate) -> bool:
"""Return True if a predicate cannot be modified manually."""
@abc.abstractmethod
def create(self, node_type: schema.Node, guids: typing.Iterable[URI]):
"""Perform post-creation operations on nodes, e.g. ownership information."""
@abc.abstractmethod
def link_from_node(self, node_type: schema.Node, guids: typing.Iterable[URI]) -> typing.Iterable[URI]:
"""Return nodes for which outbound links can be written."""
@abc.abstractmethod
def link_to_node(self, node_type: schema.Node, guids: typing.Iterable[URI]) -> typing.Iterable[URI]:
"""Return nodes for which inbound links can be written."""
@abc.abstractmethod
def write_literal(self, node_type: schema.Node, guids: typing.Iterable[URI]) -> typing.Iterable[URI]:
"""Return nodes to which literals can be attached."""
@abc.abstractmethod
def createable(self, node_type: schema.Node, guids: typing.Iterable[URI]) -> typing.Iterable[URI]:
"""Return nodes that are allowed to be created."""
@abc.abstractmethod
def filter_read(self, node_type: schema.Node, query: ast.filter.FilterExpression) -> ast.filter.FilterExpression:
"""Re-write a filter *query* to get (i.e., read) *node_type* nodes."""
## EOF ##
|
