check potential issue with change of collection body

README.md

@@ -43,7 +43,12 @@ For more than millions of records it is recommended to either set a low connecti
 
 ### Hydration
 
-To configure **stac-fastapi-pgstac** to [hydrate search result items in the API](https://stac-utils.github.io/pgstac/pgstac/#runtime-configurations), set the `USE_API_HYDRATE` environment variable to `true` or explicitly set the option in the PGStac Settings object.
+To configure **stac-fastapi-pgstac** to [hydrate search result items at the API level](https://stac-utils.github.io/pgstac/pgstac/#runtime-configurations), set the `USE_API_HYDRATE` environment variable to `true`. If `false` (default) the hydration will be done in the database.
+
+| use_api_hydrat (API) | nohydrate (PgSTAC) | Hydration |
+|                  --- |                --- |       --- |
+|                False |              False |    PgSTAC |
+|                 True |               True |       API |
 
 ### Migrations
 

stac_fastapi/pgstac/config.py

@@ -174,6 +174,16 @@ class Settings(ApiSettings):
 
     prefix_path: str = ""
     use_api_hydrate: bool = False
+    """
+    When USE_API_HYDRATE=TRUE, PgSTAC database will receive `NO_HYDRATE=TRUE`
+
+    | use_api_hydrate | nohydrate | Hydration |
+    |             --- |       --- |       --- |
+    |           False |     False |    PgSTAC |
+    |            True |      True |       API |
+
+    ref: https://stac-utils.github.io/pgstac/pgstac/#runtime-configurations
+    """
     invalid_id_chars: List[str] = DEFAULT_INVALID_ID_CHARS
     base_item_cache: Type[BaseItemCache] = DefaultBaseItemCache
 

tests/conftest.py

@@ -100,7 +100,7 @@ async def pgstac(database):
 # Run all the tests that use the api_client in both db hydrate and api hydrate mode
 @pytest.fixture(
     params=[
-        # hydratation, prefix, model_validation
+        # API hydratation, prefix, model_validation
         (False, "", False),
         (False, "/router_prefix", False),
         (True, "", False),

tests/data/test2_item.json

@@ -64,7 +64,7 @@
           "nodata": 0,
           "offset": 2.03976,
           "data_type": "uint8",
-          "spatial_resolution": 60
+          "spatial_resolution": 80
         }
       ]
     },
@@ -172,7 +172,6 @@
       "type": "image/tiff; application=geotiff; profile=cloud-optimized",
       "roles": ["cloud"],
       "title": "Pixel Quality Assessment Band (QA_PIXEL)",
-      "description": "Collection 2 Level-1 Pixel Quality Assessment Band",
       "raster:bands": [
         {
           "unit": "bit index",

tests/resources/test_item.py

@@ -1722,3 +1722,71 @@ async def test_item_search_freetext(app_client, load_test_data, load_test_collec
         params={"q": "yo"},
     )
     assert resp.json()["numberReturned"] == 0
+
+
+@pytest.mark.asyncio
+async def test_item_asset_change(app_client, load_test_data):
+    """Check that changing item_assets in collection does
+    not affect existing items if hydration should not occur.
+
+    """
+    # load collection
+    data = load_test_data("test2_collection.json")
+    collection_id = data["id"]
+
+    resp = await app_client.post("/collections", json=data)
+    assert "item_assets" in data
+    assert resp.status_code == 201
+    assert "item_assets" in resp.json()
+
+    # load items
+    test_item = load_test_data("test2_item.json")
+    resp = await app_client.post(f"/collections/{collection_id}/items", json=test_item)
+    assert resp.status_code == 201
+
+    # check list of items
+    resp = await app_client.get(
+        f"/collections/{collection_id}/items", params={"limit": 1}
+    )
+    assert len(resp.json()["features"]) == 1
+    assert resp.status_code == 200
+
+    # NOTE: API or PgSTAC Hydration we should get the same values as original Item
+    assert (
+        test_item["assets"]["red"]["raster:bands"]
+        == resp.json()["features"][0]["assets"]["red"]["raster:bands"]
+    )
+
+    # NOTE: `description` is not in the item body but in the collection's item-assets
+    # because it's not in the original item it won't be hydrated
+    assert not resp.json()["features"][0]["assets"]["qa_pixel"].get("description")
+
+    ###########################################################################
+    # Remove item_assets in collection
+    operations = [{"op": "remove", "path": "/item_assets"}]
+    resp = await app_client.patch(f"/collections/{collection_id}", json=operations)
+    assert resp.status_code == 200
+
+    # Make sure item_assets is not in collection response
+    resp = await app_client.get(f"/collections/{collection_id}")
+    assert resp.status_code == 200
+    assert "item_assets" not in resp.json()
+    ###########################################################################
+
+    resp = await app_client.get(
+        f"/collections/{collection_id}/items", params={"limit": 1}
+    )
+    assert len(resp.json()["features"]) == 1
+    assert resp.status_code == 200
+
+    # NOTE: here we should only get `scale`, `offset` and `spatial_resolution`
+    # because the other values were stripped on ingestion (dehydration is a default in PgSTAC)
+    # scale and offset are no in item-asset and spatial_resolution is different, so the value in the item body is kept
+    assert ["scale", "offset", "spatial_resolution"] == list(
+        resp.json()["features"][0]["assets"]["red"]["raster:bands"][0]
+    )
+
+    # NOTE: `description` is not in the original item but in the collection's item-assets
+    # We get "𒍟※" because PgSTAC set it when ingesting (`description`is item-assets)
+    # because we removed item-assets, pgstac cannot hydrate this field, and thus return "𒍟※"
+    assert resp.json()["features"][0]["assets"]["qa_pixel"]["description"] == "𒍟※"