Feature/add collection search extension V2

[vincentsarago]

simpler version of #681

This PR doesn't add the/collections - POST endpoint because:

• it's not mandatory in the spec
• it will conflict with the transaction extension 😬

We could in another PR show (in the documentation) how to create a /collections - POST which support both search and transaction

cc @tjellicoe-tpzuk

[vincentsarago]

this is ready for review

[jonhealy1]

Cool beans!

[m-mohr]

@jonhealy1 @vincentsarago I had another look at this and I'm wondering where the queryables enpoint is exposed. The filter extension, which is listed in the conformance classes, would require to be able to query based on queryables but I don't see where the link is added. Is that done in the backends?

[vincentsarago]

Yes that should be done by the users in their application.

[m-mohr]

@vincentsarago Why though? If you have the filter extension enabled, you need the queryables link anyway. Could return an empty schema, but why this manual step?

Related PR: stac-utils/stac-fastapi-pgstac#89

[vincentsarago]

@m-mohr I'm not quite sure what you are asking to be honest. From the extension POV we cannot enforce the links to be present in the endpoints response 🤷

The /queryables endpoints in added to the application when you register a FilterExtension to the application.

if you add the FilterExtension GET model to the collection-search model (as in https://github.com/stac-utils/stac-fastapi/pull/736/files#diff-6b36639e106da8e405a2aeb7d41d08853d6688ff9b34c740309da5d22ac2816bR89-R102) it's then up to the user to also register the FilterExtension to the application itself to have the /queryables endpoint

[m-mohr]

@vincentsarago I'm missing the queryables link (not the endpoint itself) in GET /collections, similar to how it's missing for global Item Search in GET / (see stac-utils/stac-fastapi-pgstac#89 ). Maybe I'm missing something though?

If it needs to be added in the back-ends (as in the mentioned PR, although stac-utils/stac-fastapi-pgstac#89 (comment) is confusing then) it's fine, just feels conceptually a bit weird.

[vincentsarago]

👍 the links are added in the client as you did in the stac-FastAPI-pgstac PR