Required fields for links

[m-mohr]

I'm currently comparing STAC, STAC API, OGC API Features and OGC API Records link objects.
STAC API made the type recently a required field due to req 13B in OAFeat, but the schema doesn't list type as being required:
http://schemas.opengis.net/ogcapi/features/part1/1.0/openapi/schemas/link.yaml
Or does 13B only apply to self and alternate links as mentioned in req. 13A?

@pvretano In Records the schema only requires href, I think: https://github.com/opengeospatial/ogcapi-records/blob/master/core/openapi/schemas/common/link.yaml

In Commons the schema requires href and rel: https://github.com/opengeospatial/ogcapi-common/blob/master/19-072/openapi/schemas/link.yaml

I feel like there's a bit of alignment or clarification needed, not only in Features...?

[cportele]

@m-mohr

Yes, only the self and alternate links must have a type.

In the link object, only href and rel are required. This is consistent with and based on RFC 8288.

[m-mohr]

Thanks, this was greatly misunderstood by us and even lead to a spec change recently in STAC API where we required the type field in STAC API. I think it should be considered to clarify the wording... something like: "All links with relation type self and alternate SHALL include the ..."

[cportele]

Thanks for raising this. I will create a pull request (and also check, if we should make similar clarifications in other requirements).

[m-mohr]

I found at least a similar recommendation: https://github.com/opengeospatial/ogcapi-features/blob/master/core/standard/recomendations/core/REC_sfc-md-links.adoc (which somewhat contradicts with the requirement?)

And also https://github.com/opengeospatial/ogcapi-features/blob/master/core/standard/requirements/core/REQ_fc-md-items-links.adoc, https://github.com/opengeospatial/ogcapi-features/blob/master/core/standard/requirements/core/REQ_f-links.adoc, ... so it seems there are a couple of them. Thanks!

[cportele]

@m-mohr - Please have a look at #819. Thanks!