binary blob in schema and sparql triple store

3 files changed, 17 insertions, 2 deletions

diff --git a/bsfs/schema/schema.py b/bsfs/schema/schema.py
index 1644926..0de4203 100644
--- a/bsfs/schema/schema.py
+++ b/bsfs/schema/schema.py
@@ -69,6 +69,7 @@ class Schema():
         literals.add(types.ROOT_LITERAL)
         predicates.add(types.ROOT_PREDICATE)
         # add minimally necessary types to the schema
+        literals.add(types.ROOT_BLOB)
         literals.add(types.ROOT_NUMBER)
         literals.add(types.ROOT_TIME)
         literals.add(types.ROOT_ARRAY)
diff --git a/bsfs/schema/types.py b/bsfs/schema/types.py
index 3a2e10c..12e7e94 100644
--- a/bsfs/schema/types.py
+++ b/bsfs/schema/types.py
@@ -380,6 +380,11 @@ ROOT_LITERAL = Literal(
     parent=None,
     )
 
+ROOT_BLOB = Literal(
+    uri=ns.bsfs.BinaryBlob,
+    parent=ROOT_LITERAL,
+    )
+
 ROOT_NUMBER = Literal(
     uri=ns.bsfs.Number,
     parent=ROOT_LITERAL,
diff --git a/bsfs/triple_store/sparql/sparql.py b/bsfs/triple_store/sparql/sparql.py
index a0dd12e..dbf9d45 100644
--- a/bsfs/triple_store/sparql/sparql.py
+++ b/bsfs/triple_store/sparql/sparql.py
@@ -5,8 +5,11 @@ A copy of the license is provided with the project.
 Author: Matthias Baumgartner, 2022
 """
 # imports
+import base64
 import itertools
 import typing
+
+# external imports
 import rdflib
 
 # bsfs imports
@@ -30,6 +33,8 @@ __all__: typing.Sequence[str] = (
 
 ## code ##
 
+rdflib.term.bind(ns.bsfs.BinaryBlob, bytes, constructor=base64.b64decode)
+
 class _Transaction():
     """Lightweight rdflib transactions for in-memory databases."""
 
@@ -242,7 +247,7 @@ class SparqlStore(base.TripleStoreBase):
             ) -> typing.Iterator[URI]:
         if node_type not in self.schema.nodes():
             raise errors.ConsistencyError(f'{node_type} is not defined in the schema')
-        if not isinstance(filter, ast.filter.FilterExpression):
+        if filter is not None and not isinstance(filter, ast.filter.FilterExpression):
             raise TypeError(filter)
         # compose query
         query = self._filter_parser(node_type, filter)
@@ -334,7 +339,11 @@ class SparqlStore(base.TripleStoreBase):
             guid = rdflib.URIRef(guid)
             # convert value
             if isinstance(predicate.range, bsc.Literal):
-                value = rdflib.Literal(value, datatype=rdflib.URIRef(predicate.range.uri))
+                dtype = rdflib.URIRef(predicate.range.uri)
+                if predicate.range <= self.schema.literal(ns.bsfs.BinaryBlob):
+                    dtype = rdflib.URIRef(ns.bsfs.BinaryBlob)
+                    value = base64.b64encode(value)
+                value = rdflib.Literal(value, datatype=dtype)
             elif isinstance(predicate.range, bsc.Node):
                 value = rdflib.URIRef(value)
             else: