Fixing error when retrieving the TMS in vector tiles that do not provide tilejson metadata (#1288)

* - look for metadata.json, only when we are using the tilejson format; in other cases, this file is missing and that is going to make pygeoapi fail

* - updated configuration examples in documentation, to use "default" as metadata for vector tiles ("raw" does not work)
- added metadata format configuration for the pg_tileserv provider example

docs/source/data-publishing/ogcapi-tiles.rst

@@ -54,7 +54,7 @@ This code block shows how to configure pygeoapi to read Mapbox vector tiles, fro
          data: tests/data/tiles/ne_110m_lakes  # local directory tree
          # data: http://localhost:9000/ne_110m_lakes/{z}/{x}/{y}.pbf # tiles stored on a MinIO bucket
          options:
-             metadata_format: raw # default | tilejson
+             metadata_format: default # default | tilejson
              zoom:
                  min: 0
                  max: 5
@@ -75,7 +75,7 @@ This code block shows how to configure pygeoapi to read Mapbox vector tiles, fro
          # if you don't use precision 0, you will be requesting for aggregations which are not supported in the 
          # free version of elastic
          options:
-             metadata_format: raw # default | tilejson
+             metadata_format: default # default | tilejson
              zoom:
                  min: 0
                  max: 5
@@ -94,6 +94,7 @@ This code block shows how to configure pygeoapi to read Mapbox vector tiles, fro
               name: MVT
               data: http://localhost:7800/public.ne_50m_admin_0_countries/{z}/{x}/{y}.pbf
               options:
+                metadata_format: default # default | tilejson
                 zoom:
                     min: 0
                     max: 16

pygeoapi/provider/mvt.py

@@ -257,11 +257,12 @@ class MVTProvider(BaseTileProvider):
         if is_url(self.data):
             url = urlparse(self.data)
             base_url = f'{url.scheme}://{url.netloc}'
-            with requests.Session() as session:
-                session.get(base_url)
-                resp = session.get(f'{base_url}/{layer}/metadata.json')
-                resp.raise_for_status()
-            metadata_json_content = resp.json()
+            if metadata_format == TilesMetadataFormat.TILEJSON:
+                with requests.Session() as session:
+                    session.get(base_url)
+                    resp = session.get(f'{base_url}/{layer}/metadata.json')
+                    resp.raise_for_status()
+                metadata_json_content = resp.json()
         else:
             if not isinstance(self.service_metadata_url, Path):
                 msg = f'Wrong data path configuration: {self.service_metadata_url}'  # noqa