[MCC-1498582] - Create layered design

README.md

@@ -38,8 +38,7 @@ with DataConnectClient.connect(
     token="your-bearer-token",
 ) as client:
 
-    studies = client.studies(search_study_name="ACME", page=1, page_size=10)
-    study = studies[0]
+    studies = client.get_studies(search_study_name="ACME")
 ```
 ## Development
 

dataconnect/service/default.py

@@ -69,7 +69,7 @@ def get_studies(self) -> list[Study]:
 
         try:
             return [resource_to_study(r) for r in resources]
-        except (KeyError, TypeError, ValueError) as ex:
+        except (IndexError, KeyError, TypeError, ValueError) as ex:
             raise ValidationError(f"Unexpected studies response format: {ex}") from ex
 
     def close(self) -> None:

dataconnect/service/mappers.py

@@ -10,13 +10,17 @@
 import json
 from uuid import UUID
 
+from dataconnect.exceptions import NotFoundError
 from dataconnect.models import Study, StudyEnvironment
 from dataconnect.transport.models import ResourceInfo
 
 
 def resource_to_study(resource: ResourceInfo) -> Study:
     """Parse a transport-layer ``ResourceInfo`` into a ``Study`` domain object."""
 
+    if not resource or not resource.endpoints or not resource.endpoints[0].ticket:
+        raise NotFoundError("Invalid resource: missing endpoints or ticket")
+
     data = json.loads(resource.endpoints[0].ticket.decode("utf-8"))
 
     return Study(

dataconnect/transport/arrow_flight/transport.py

@@ -77,7 +77,9 @@ def list_resources(self, request: ResourceQuery) -> list[ResourceInfo]:
         flight_type = _ACTION_FLIGHT_TYPE.get(request.action)
 
         if flight_type is None:
-            raise TransportConnectionError(f"Unknown action: {request.action!r}")
+            raise TransportStatusError(
+                f"Unknown action: {request.action!r}", status_code=3, grpc_status="INVALID_ARGUMENT"
+            )
 
         body = json.loads(request.body) if request.body else {}
         criteria = json.dumps({**body, "flight_type": flight_type}, separators=(",", ":")).encode("utf-8")