Issue #699 fixup item_assets handling for pystac<1.12

Support for STAC 1.1 item_assets through `Collection.item_assets`
is only available since 1.12. Below that DIY dict handling is necessary.

Author: soxofaan

openeo/metadata.py

@@ -768,6 +768,7 @@ def _band_from_eo_bands_metadata(self, band: Union[dict, pystac.extensions.eo.Ba
 
     def _band_from_common_bands_metadata(self, data: dict) -> Band:
         """Construct band from metadata dict in STAC 1.1 + eo v2 style metadata"""
+        # TODO: also support pystac wrapper when available (pystac v2?)
         return Band(
             name=data["name"],
             common_name=data.get("eo:common_name"),
@@ -819,6 +820,13 @@ def bands_from_stac_collection(
             return self._bands_from_item_assets(collection.item_assets)
         elif _PYSTAC_1_9_EXTENSION_INTERFACE and collection.ext.has("item_assets") and collection.ext.item_assets:
             return self._bands_from_item_assets(collection.ext.item_assets)
+        elif "item_assets" in collection.extra_fields:
+            # Workaround for lack of support for STAC 1.1 core item_assets with pystac < 1.12
+            item_assets = {
+                k: pystac.extensions.item_assets.AssetDefinition(properties=v, owner=collection)
+                for k, v in collection.extra_fields["item_assets"].items()
+            }
+            return self._bands_from_item_assets(item_assets)
         # If no band metadata so far: traverse items in collection
         elif consult_items:
             bands = _BandList.merge(
@@ -894,6 +902,8 @@ def _bands_from_item_asset_definition(
                 if _PYSTAC_1_9_EXTENSION_INTERFACE and asset.owner and not asset.ext.has("eo"):
                     self._warn_undeclared_metadata(field="eo:bands", ext="eo")
                 return _BandList(self._band_from_eo_bands_metadata(b) for b in asset.properties["eo:bands"])
+        else:
+            self._warn(f"_bands_from_item_asset_definition: unsupported {type(asset)=}")
         return _BandList([])
 
     def _bands_from_item_assets(

tests/test_metadata.py

@@ -1736,9 +1736,12 @@ def test_bands_from_stac_asset(self, data, expected):
                 ["Deriving band listing from unordered `item_assets`"],
             ),
             (
-                # STAC 1.0, with "eo" extension is used for band metadata, but not declared
+                # STAC 1.0, with "eo" extension used for band metadata, but not declared
                 StacDummyBuilder.collection(
                     stac_version="1.0.0",
+                    stac_extensions=[
+                        "https://stac-extensions.github.io/item-assets/v1.0.0/schema.json",
+                    ],
                     item_assets={
                         "asset1": {"eo:bands": [{"name": "B03"}, {"name": "B02"}]},
                         "asset2": {"eo:bands": [{"name": "B04"}]},
@@ -1763,7 +1766,7 @@ def test_bands_from_stac_asset(self, data, expected):
                 ["Deriving band listing from unordered `item_assets`"],
             ),
             (
-                # STAC 1.1 Collection with "eo" extension
+                # STAC 1.1 Collection with "eo" extension based band metadata
                 StacDummyBuilder.collection(
                     stac_version="1.1.0",
                     stac_extensions=[
@@ -1784,7 +1787,9 @@ def test_bands_from_stac_collection_with_item_assets(
     ):
         collection = pystac.Collection.from_dict(stac_data)
         assert _StacMetadataParser().bands_from_stac_collection(collection).band_names() == expected_bands
-        assert caplog.messages == expected_warnings
+
+        if _PYSTAC_1_9_EXTENSION_INTERFACE:
+            assert caplog.messages == expected_warnings
 
     @pytest.mark.parametrize(
         ["path", "expected"],