Merge branch 'develop' into main

1 files changed, 71 insertions, 0 deletions

diff --git a/bsfs/graph/ac/base.py b/bsfs/graph/ac/base.py
new file mode 100644
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+++ b/bsfs/graph/ac/base.py
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+"""
+
+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.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."""
+
+
+## EOF ##