GET with '?data_source=<name>' works.

tiled/catalog/adapter.py

@@ -283,9 +283,18 @@ def __init__(
         self.ancestors = node.ancestors
         self.key = node.key
         self.access_policy = access_policy
-        self.data_source_name = data_source_name
         self.startup_tasks = [self.startup]
         self.shutdown_tasks = [self.shutdown]
+        if data_source_name is not None:
+            for data_source in self.data_sources:
+                if data_source_name == data_source.name:
+                    self.data_source_structure_family = data_source.structure_family
+                    break
+            else:
+                raise ValueError(f"No DataSource named {data_source_name} on this node")
+            self.data_source = data_source
+        elif len(self.data_sources) == 1:
+            (self.data_source,) = self.data_sources
 
     def metadata(self):
         return self.node.metadata_
@@ -443,30 +452,20 @@ async def lookup_adapter(
         )
 
     async def get_adapter(self):
-        num_data_sources = len(self.data_sources)
-        if self.data_source_name is not None:
-            for data_source in self.data_sources:
-                if self.data_source_name == data_source.name:
-                    break
-            else:
-                raise ValueError(
-                    f"No DataSource named {self.data_source_name} on this node"
-                )
-        elif num_data_sources > 1:
-            raise ValueError(
-                "A data_source_name is required because this node "
-                f"has {num_data_sources} data sources"
+        if (self.structure_family == StructureFamily.union) and not self.data_source:
+            raise RuntimeError(
+                "A data_source_name must be specified at construction time."
             )
-        else:
-            (data_source,) = self.data_sources
         try:
-            adapter_factory = self.context.adapters_by_mimetype[data_source.mimetype]
+            adapter_factory = self.context.adapters_by_mimetype[
+                self.data_source.mimetype
+            ]
         except KeyError:
             raise RuntimeError(
-                f"Server configuration has no adapter for mimetype {data_source.mimetype!r}"
+                f"Server configuration has no adapter for mimetype {self.data_source.mimetype!r}"
             )
         parameters = collections.defaultdict(list)
-        for asset in data_source.assets:
+        for asset in self.data_source.assets:
             if asset.parameter is None:
                 continue
             scheme = urlparse(asset.data_uri).scheme
@@ -495,10 +494,10 @@ async def get_adapter(self):
             else:
                 parameters[asset.parameter].append(asset.data_uri)
         adapter_kwargs = dict(parameters)
-        adapter_kwargs.update(data_source.parameters)
+        adapter_kwargs.update(self.data_source.parameters)
         adapter_kwargs["specs"] = self.node.specs
         adapter_kwargs["metadata"] = self.node.metadata_
-        adapter_kwargs["structure"] = data_source.structure
+        adapter_kwargs["structure"] = self.data_source.structure
         adapter_kwargs["access_policy"] = self.access_policy
         adapter = await anyio.to_thread.run_sync(
             partial(adapter_factory, **adapter_kwargs)
@@ -1007,7 +1006,9 @@ async def write_partition(self, *args, **kwargs):
 
 
 class CatalogUnionAdapter(CatalogNodeAdapter):
-    # This does not support direct reading or writing.
+    # def get(self, key):
+    #     for data_source in data_sources:
+    #         if data_source.name ==
 
     async def read(self, *args, **kwargs):
         return await ensure_awaitable((await self.get_adapter()).read, *args, **kwargs)

tiled/server/dependencies.py

@@ -11,6 +11,7 @@
     serialization_registry as default_serialization_registry,
 )
 from ..query_registration import query_registry as default_query_registry
+from ..structures.core import StructureFamily
 from ..validation_registration import validation_registry as default_validation_registry
 from .authentication import get_current_principal, get_session_state
 from .core import NoEntry
@@ -48,7 +49,7 @@ def get_root_tree():
     )
 
 
-def SecureEntry(scopes):
+def SecureEntry(scopes, structure_families=None):
     async def inner(
         path: str,
         request: Request,
@@ -119,7 +120,36 @@ async def inner(
                             )
         except NoEntry:
             raise HTTPException(status_code=404, detail=f"No such entry: {path_parts}")
-        return entry
+        # Fast path for the common successful case
+        if (structure_families is None) or (
+            entry.structure_family in structure_families
+        ):
+            return entry
+        # Handle union structure_family
+        if entry.structure_family == StructureFamily.union:
+            if not data_source:
+                raise HTTPException(
+                    status_code=400, detail="A data_source query parameter is required."
+                )
+            if entry.data_source.structure_family in structure_families:
+                return entry
+            raise HTTPException(
+                status_code=404,
+                detail=(
+                    f"The data source named {data_source} backing the node "
+                    f"at {path} has structure family {entry.data_source.structure_family} "
+                    "and this endpoint is compatible with structure families "
+                    f"{structure_families}"
+                ),
+            )
+        raise HTTPException(
+            status_code=404,
+            detail=(
+                f"The node at {path} has structure family {entry.structure_family} "
+                "and this endpoint is compatible with structure families "
+                f"{structure_families}"
+            ),
+        )
 
     return Security(inner, scopes=scopes)