Coverages: continue TIFF implementation; rangeset

- Add an endpoint implementation to return a coverage as a TIFF (not
  yet fully functional due to problems with rioxarray)

- Add a dummy implementation of the recently-deprecated rangeSet
  endpoint. It returns a 501 status to make it clear that the
  endpoint is deliberately not supported.

xcube/webapi/ows/coverages/controllers.py

@@ -18,11 +18,14 @@
 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 # DEALINGS IN THE SOFTWARE.
-
+from xcube.server.api import ApiRequest
 from xcube.webapi.datasets.context import DatasetsContext
+import os
+import tempfile
 import xarray as xr
 import pyproj
 import numpy as np
+import rasterio
 
 
 def get_coverage_as_json(ctx: DatasetsContext, collection_id: str):
@@ -45,9 +48,35 @@ def get_coverage_as_json(ctx: DatasetsContext, collection_id: str):
     }
 
 
-def get_coverage_as_tiff(ctx: DatasetsContext, collection_id: str):
+def get_coverage_as_tiff(ctx: DatasetsContext, collection_id: str,
+                         request: ApiRequest, content_type: str):
+    query = request.query
     ds = get_dataset(ctx, collection_id)
-    return ds.
+    if 'bbox' in query:
+        bbox = list(map(float, query['bbox'][0].split(',')))
+        ds = ds.sel(lat=slice(bbox[0], bbox[2]), lon=slice(bbox[1], bbox[3]))
+    if 'datetime' in query:
+        timespec = query['datetime']
+        if '/' in timespec:
+            timefrom, timeto = timespec[0].split('/')
+            ds = ds.sel(time=slice(timefrom, timeto))
+        else:
+            ds = ds.sel(time=timespec, method='nearest').squeeze()
+    if 'properties' in query:
+        vars_to_keep = set(query['properties'][0].split(','))
+        data_vars = set(ds.data_vars)
+        vars_to_drop = list(data_vars - vars_to_keep)
+        ds = ds.drop_vars(vars_to_drop)
+    return dataset_to_tiff(ds)
+
+
+def dataset_to_tiff(ds):
+    with tempfile.TemporaryDirectory() as tempdir:
+        path = os.path.join(tempdir, 'out.tiff')
+        ds.rio.to_raster(path)
+        with open(path, 'rb') as fh:
+            data = fh.read()
+    return data
 
 
 def get_coverage_domainset(ctx: DatasetsContext, collection_id: str):
@@ -122,8 +151,9 @@ def get_crs_from_dataset(ds: xr.Dataset):
         if var_name in ds.variables:
             var = ds[var_name]
             if 'spatial_ref' in var.attrs:
-                crs_string = ds.spatial_ref.attrs['spatial_ref']
+                crs_string = ds[var_name].attrs['spatial_ref']
                 return pyproj.crs.CRS(crs_string).to_string()
+    return 'EPSG:4326'
 
 
 def get_coverage_rangetype(ctx: DatasetsContext, collection_id: str):

xcube/webapi/ows/coverages/routes.py

@@ -48,7 +48,7 @@ async def get(self, collectionId: str):
             result = get_coverage_as_json(ds_ctx, collectionId)
         else:
             actual_content_type='image/tiff'
-            result = get_coverage_as_tiff()
+            result = get_coverage_as_tiff(ds_ctx, collectionId, self.request, content_type)
         return await self.response.finish(result,
                                           content_type=actual_content_type)
 
@@ -86,12 +86,24 @@ async def get(self, collectionId: str):
         ))
 
 
+@api.route('/catalog/collections/{collectionId}/coverage/rangeset')
+class CoveragesRangesetHandler(ApiHandler[CoveragesContext]):
+    # noinspection PyPep8Naming
+    @api.operation(operation_id='coveragesRangeset',
+                   summary='OGC API - Coverages - rangeset')
+    async def get(self, collectionId: str):
+        self.response.set_status(501)
+        return self.response.finish(
+            'The rangeset endpoint has been deprecated and is not supported.'
+        )
+
+
 def get_content_type(
         request: ApiRequest, available: Optional[Collection[str]] = None
     ) -> Optional[str]:
     if 'f' in request.query:  # overrides headers
         content_type = request.query['f'][0]
-        return content_type if content_type in available else None
+        return content_type if available is None or content_type in available else None
 
     accept = re.split(', *', request.headers.get('Accept'))