Add method to fetch a given property from multiple entities. (#309)

simple/util/dc_client.py

@@ -56,8 +56,8 @@
 # Make the implementation more generic if more entity types are resolved via mapping functions.
 _S2CELL_ENTITY_TYPE_PATTERN = r"S2CellLevel(\d+)"
 
-# The maximum number of entities to include in a single DC resolve call.
-_RESOLVE_BATCH_SIZE = 500
+# The maximum number of entities to include in a single DC call.
+_BATCH_SIZE = 500
 
 _HTTPX_LIMITS = Limits(max_keepalive_connections=5, max_connections=10)
 
@@ -104,7 +104,7 @@ async def resolve_place_entities_async(
     entity_type: str = None,
     property_name: str = "description") -> dict[str, str]:
 
-  chunks = chunked(entities, _RESOLVE_BATCH_SIZE)
+  chunks = chunked(entities, _BATCH_SIZE)
 
   resolved: dict[str, str] = {}
   async with AsyncClient(limits=_HTTPX_LIMITS, timeout=None) as client:
@@ -187,7 +187,7 @@ def resolve_non_place_entities(entities: list[str],
 
 # TODO: Cache results to file and return from cache if present.
 def get_entities_of_type(entity_type: str,
-                         next_token: str = None) -> (dict[str, str], str):
+                         next_token: str = None) -> tuple[dict[str, str], str]:
   data = {
       "nodes": [entity_type],
       "property": "<-typeOf",
@@ -244,6 +244,50 @@ def resolve_entity_type(entity_dcids: list[str]) -> str:
   return common_entity_types.pop() if common_entity_types else ""
 
 
+def get_property_of_entities(entities: list[str],
+                             property_name: str) -> dict[str, str]:
+  return asyncio.run(get_property_of_entities_async(entities, property_name))
+
+
+async def get_property_of_entities_async(entities: list[str],
+                                         property_name: str) -> dict[str, str]:
+
+  chunks = chunked(entities, _BATCH_SIZE)
+
+  result: dict[str, str] = {}
+  async with AsyncClient(limits=_HTTPX_LIMITS, timeout=None) as client:
+    futures: dict[str, str] = [
+        _get_property_of_entities_chunk(client, chunk, property_name)
+        for chunk in chunks
+    ]
+    for result_chunk in await asyncio.gather(*futures):
+      result.update(result_chunk)
+
+  return result
+
+
+async def _get_property_of_entities_chunk(client: AsyncClient,
+                                          entities_chunk: list[str],
+                                          property_name: str) -> dict[str, str]:
+  data = {
+      "nodes": entities_chunk,
+      "property": f"->{property_name}",
+  }
+
+  logging.debug("Fetching nodes: %s", data)
+  # TODO: handle pagination.
+  response = await post_async(client, path="/v2/node", data=data)
+
+  result_chunk: dict[str, str] = {}
+  for entity_dcid, entity_data in response.get("data", {}).items():
+    nodes = entity_data.get("arcs", {}).get(property_name, {}).get("nodes", [])
+    values = [node.get("value") for node in nodes if node.get("value")]
+    if values:
+      result_chunk[entity_dcid] = values[0]
+
+  return result_chunk
+
+
 def post(path: str, data={}) -> dict:
   url = get_api_root() + path
   headers = {"Content-Type": "application/json"}