OpenAPI support

[dr-jts]

Might be nice to provide an OpenAPI schema and UI.

Here's some artifacts to bootstrap from:

• Go code to generate base OpenAPI JSON schema (uses https://github.com/getkin/kin-openapi)
• Go code for API response structs for schemas
• Template for Swagger UI page

[plant99]

Hi @dr-jts / @pramsey is this still relevant? I'd love to work on this. The linked code to generate OpenAPI json doesn't exist.

I tried to go to older commits from January 2020, no luck. But I can work on them using the mentioned library.

[eldang]

This has suddenly become important to me (TLDR: a client wants to include checking APIs for consistency with OpenAPI schemas in the acceptance criteria for a project I plan to use pg_tileserv for). I have some experience with both Go and Swagger, so I'll see if I can make a PR for it.

@plant99 are you still interested? If so it might be good to collaborate on it.

[dr-jts]

Sounds like a great idea.

I've fixed the broken links to the relevant pg_featureserv code.

[pramsey]

See also #126

Very happy to see this.

[plant99]

@eldang please feel free to take this up.

[eldang]

BTW, I got delayed on this because the client's priorities shifted so my last couple of PRs have come out of addressing their top concerns. But now that I've got to know this code base a bit with those, I should be able to get this done some time in December.