Remove neo4j bloom labels from graph schema (#18564)

Neo4j tools use particular node labels and relationship types to store
metadata, but are irrelevant for text2cypher or graph generation, so we
want to ignore them in the schema representation.

libs/community/langchain_community/graphs/neo4j_graph.py

@@ -6,12 +6,14 @@ from langchain_community.graphs.graph_document import GraphDocument
 from langchain_community.graphs.graph_store import GraphStore
 
 BASE_ENTITY_LABEL = "__Entity__"
+EXCLUDED_LABELS = ["_Bloom_Perspective_", "_Bloom_Scene_"]
+EXCLUDED_RELS = ["_Bloom_HAS_SCENE_"]
 
 node_properties_query = """
 CALL apoc.meta.data()
 YIELD label, other, elementType, type, property
 WHERE NOT type = "RELATIONSHIP" AND elementType = "node" 
-  AND NOT label IN [$BASE_ENTITY_LABEL]
+  AND NOT label IN $EXCLUDED_LABELS
 WITH label AS nodeLabels, collect({property:property, type:type}) AS properties
 RETURN {labels: nodeLabels, properties: properties} AS output
 
@@ -21,6 +23,7 @@ rel_properties_query = """
 CALL apoc.meta.data()
 YIELD label, other, elementType, type, property
 WHERE NOT type = "RELATIONSHIP" AND elementType = "relationship"
+      AND NOT label in $EXCLUDED_LABELS
 WITH label AS nodeLabels, collect({property:property, type:type}) AS properties
 RETURN {type: nodeLabels, properties: properties} AS output
 """
@@ -30,8 +33,8 @@ CALL apoc.meta.data()
 YIELD label, other, elementType, type, property
 WHERE type = "RELATIONSHIP" AND elementType = "node"
 UNWIND other AS other_node
-WITH * WHERE NOT label IN [$BASE_ENTITY_LABEL] 
-    AND NOT other_node IN [$BASE_ENTITY_LABEL]
+WITH * WHERE NOT label IN $EXCLUDED_LABELS
+    AND NOT other_node IN $EXCLUDED_LABELS
 RETURN {start: label, type: property, end: toString(other_node)} AS output
 """
 
@@ -243,19 +246,21 @@ class Neo4jGraph(GraphStore):
         node_properties = [
             el["output"]
             for el in self.query(
-                node_properties_query, params={"BASE_ENTITY_LABEL": BASE_ENTITY_LABEL}
+                node_properties_query,
+                params={"EXCLUDED_LABELS": EXCLUDED_LABELS + [BASE_ENTITY_LABEL]},
             )
         ]
         rel_properties = [
             el["output"]
             for el in self.query(
-                rel_properties_query, params={"BASE_ENTITY_LABEL": BASE_ENTITY_LABEL}
+                rel_properties_query, params={"EXCLUDED_LABELS": EXCLUDED_RELS}
             )
         ]
         relationships = [
             el["output"]
             for el in self.query(
-                rel_query, params={"BASE_ENTITY_LABEL": BASE_ENTITY_LABEL}
+                rel_query,
+                params={"EXCLUDED_LABELS": EXCLUDED_LABELS + [BASE_ENTITY_LABEL]},
             )
         ]
 

libs/community/tests/integration_tests/graphs/test_neo4j.py

@@ -56,13 +56,13 @@ def test_cypher_return_correct_schema() -> None:
     graph.refresh_schema()
 
     node_properties = graph.query(
-        node_properties_query, params={"BASE_ENTITY_LABEL": BASE_ENTITY_LABEL}
+        node_properties_query, params={"EXCLUDED_LABELS": [BASE_ENTITY_LABEL]}
     )
     relationships_properties = graph.query(
-        rel_properties_query, params={"BASE_ENTITY_LABEL": BASE_ENTITY_LABEL}
+        rel_properties_query, params={"EXCLUDED_LABELS": [BASE_ENTITY_LABEL]}
     )
     relationships = graph.query(
-        rel_query, params={"BASE_ENTITY_LABEL": BASE_ENTITY_LABEL}
+        rel_query, params={"EXCLUDED_LABELS": [BASE_ENTITY_LABEL]}
     )
 
     expected_node_properties = [
@@ -249,3 +249,27 @@ def test_neo4j_add_data_base_source() -> None:
         {"label": [BASE_ENTITY_LABEL, "foo"], "count": 1},
     ]
     assert graph.structured_schema["metadata"]["constraint"] != []
+
+
+def test_neo4j_filtering_labels() -> None:
+    """Test that neo4j correctly filters excluded labels."""
+    url = os.environ.get("NEO4J_URI")
+    username = os.environ.get("NEO4J_USERNAME")
+    password = os.environ.get("NEO4J_PASSWORD")
+    assert url is not None
+    assert username is not None
+    assert password is not None
+
+    graph = Neo4jGraph(url=url, username=username, password=password, sanitize=True)
+    # Delete all nodes in the graph
+    graph.query("MATCH (n) DETACH DELETE n")
+    # Remove all constraints
+    graph.query("CALL apoc.schema.assert({}, {})")
+    graph.query(
+        "CREATE (:`_Bloom_Scene_`)-[:_Bloom_HAS_SCENE_]->(:`_Bloom_Perspective_`)"
+    )
+    graph.refresh_schema()
+
+    # Assert both are empty
+    assert graph.structured_schema["node_props"] == {}
+    assert graph.structured_schema["relationships"] == []