add fields extension, tests

Author: jonhealy1

stac_fastapi/core/stac_fastapi/core/core.py

@@ -225,11 +225,13 @@ async def landing_page(self, **kwargs) -> stac_types.LandingPage:
         return landing_page
 
     async def all_collections(
-        self, sortby: Optional[str] = None, **kwargs
+        self, fields: Optional[List[str]] = None, sortby: Optional[str] = None, **kwargs
     ) -> stac_types.Collections:
         """Read all collections from the database.
 
         Args:
+            fields (Optional[List[str]]): Fields to include or exclude from the results.
+            sortby (Optional[str]): Sorting options for the results.
             **kwargs: Keyword arguments from the request.
 
         Returns:
@@ -240,6 +242,15 @@ async def all_collections(
         limit = int(request.query_params.get("limit", os.getenv("STAC_ITEM_LIMIT", 10)))
         token = request.query_params.get("token")
 
+        # Process fields parameter for filtering collection properties
+        includes, excludes = set(), set()
+        if fields and self.extension_is_enabled("FieldsExtension"):
+            for field in fields:
+                if field[0] == "-":
+                    excludes.add(field[1:])
+                else:
+                    includes.add(field[1:] if field[0] in "+ " else field)
+
         sort = None
         if sortby:
             parsed_sort = []
@@ -259,6 +270,15 @@ async def all_collections(
             token=token, limit=limit, request=request, sort=sort
         )
 
+        # Apply field filtering if fields parameter was provided
+        if fields and self.extension_is_enabled("FieldsExtension"):
+            filtered_collections = [
+                filter_fields(collection, includes, excludes)
+                for collection in collections
+            ]
+        else:
+            filtered_collections = collections
+
         links = [
             {"rel": Relations.root.value, "type": MimeTypes.json, "href": base_url},
             {"rel": Relations.parent.value, "type": MimeTypes.json, "href": base_url},
@@ -273,7 +293,7 @@ async def all_collections(
             next_link = PagingLinks(next=next_token, request=request).link_next()
             links.append(next_link)
 
-        return stac_types.Collections(collections=collections, links=links)
+        return stac_types.Collections(collections=filtered_collections, links=links)
 
     async def get_collection(
         self, collection_id: str, **kwargs

stac_fastapi/tests/api/test_api_search_collections.py

@@ -77,3 +77,78 @@ async def test_collections_sort_id_desc(app_client, txn_client, load_test_data):
     assert len(test_collections) == len(collection_ids)
     for i, expected_id in enumerate(sorted_ids):
         assert test_collections[i]["id"] == expected_id
+
+
+@pytest.mark.asyncio
+async def test_collections_fields(app_client, txn_client, load_test_data):
+    """Verify GET /collections honors the fields parameter."""
+    # Create multiple collections with different ids
+    base_collection = load_test_data("test_collection.json")
+
+    # Create collections with ids in a specific order to test fields
+    # Use unique prefixes to avoid conflicts between tests
+    test_prefix = f"fields-{uuid.uuid4().hex[:8]}"
+    collection_ids = [f"{test_prefix}-a", f"{test_prefix}-b", f"{test_prefix}-c"]
+
+    for i, coll_id in enumerate(collection_ids):
+        test_collection = base_collection.copy()
+        test_collection["id"] = coll_id
+        test_collection["title"] = f"Test Collection {i}"
+        test_collection["description"] = f"Description for collection {i}"
+        await create_collection(txn_client, test_collection)
+
+    # Test include fields parameter
+    resp = await app_client.get(
+        "/collections",
+        params=[("fields", "id"), ("fields", "title")],
+    )
+    assert resp.status_code == 200
+    resp_json = resp.json()
+
+    # Check if collections exist in the response
+    assert "collections" in resp_json, "No collections in response"
+
+    # Filter collections to only include the ones we created for this test
+    test_collections = []
+    for c in resp_json["collections"]:
+        if "id" in c and c["id"].startswith(test_prefix):
+            test_collections.append(c)
+
+    # Filter collections to only include the ones we created for this test
+    test_collections = []
+    for c in resp_json["collections"]:
+        if "id" in c and c["id"].startswith(test_prefix):
+            test_collections.append(c)
+
+    # Collections should only have id and title fields
+    for collection in test_collections:
+        assert "id" in collection
+        assert "title" in collection
+        assert "description" not in collection
+        assert "links" in collection  # links are always included
+
+    # Test exclude fields parameter
+    resp = await app_client.get(
+        "/collections",
+        params=[("fields", "-description")],
+    )
+    assert resp.status_code == 200
+    resp_json = resp.json()
+
+    # Check if collections exist in the response
+    assert (
+        "collections" in resp_json
+    ), "No collections in response for exclude fields test"
+
+    # Filter collections to only include the ones we created for this test
+    test_collections = []
+    for c in resp_json["collections"]:
+        if "id" in c and c["id"].startswith(test_prefix):
+            test_collections.append(c)
+
+    # Collections should have all fields except description
+    for collection in test_collections:
+        assert "id" in collection
+        assert "title" in collection
+        assert "description" not in collection
+        assert "links" in collection