OpenLayers OGCVectorTile type syntax issue

[mikefedak]

Description

OpenLayers OGCVectorTile expects a "type" property in the links returned by pygeoapi. It is currently getting "type_" which causes an error when attempting to load vector tiles.

Steps to Reproduce
Added a postgres tile provider (MVT-postgresql) for a vector dataset and then attempted to load the tiles within openlayers using OGCVectorTile .

Expected behavior
Layer loads on the map as expected.

Screenshots/Tracebacks

In the console, this error looks like:

 Error: Could not find "item" link
      getVectorTileUrlTemplate ogcTileUtil.js:242
      parseTileSetMetadata ogcTileUtil.js:456
      getTileSetInfo ogcTileUtil.js:503
      promise callback*getTileSetInfo ogcTileUtil.js:502
      OGCVectorTile OGCVectorTile.js:84

Going to the server and looking at the response for a mvt query, it includes this:

  {
    "rel": "item",
    "type_": "application/vnd.mapbox-vector-tile",   // ← should be "type"
    "href": ".../tiles/WebMercatorQuad/{tileMatrix}/{tileRow}/{tileCol}?f=mvt"
  }

Tracing this back,

 pygeoapi/provider/mvt_postgresql.py, line 250-252:
 service_url_link = LinkType(href=service_url, rel='item',
                                    type_=service_url_link_type,
                                    title=service_url_link_title)

and pygeoapi/models/provider/base.py line 153-159

I understand that type_ is being used as type is a reserved word. I had initially made a workaround on the front end whereas I reconstructed the url and just used the generic vector tiles type in OpenLayers however I would prefer if this worked properly so I changed the LinkType base model to use a pydantic alias:

from pydantic import BaseModel, Field

class LinkType(BaseModel):
    type_: Optional[str] = Field(None, alias='type', serialization_alias='type')

Then I also changed to return by alias: pygeoapi/provider/mvt_postgresql.py and the get_default_metadata function:

return content.model_dump(exclude_none=True, by_alias=True)

This fixed it. However, all of the mvt get_default_metadata functions would need to be updated.

Environment

• OS: Windows
• Python version: 3.14.4
• pygeoapi version: master