OpenAPI: Add Basic Auth to the REST spec

[roryqi]

Updated the OpenAPI specification to include Basic Authentication, reflecting the support already present in the Iceberg RESTCatalog. I'm uncertain if we need to initiate a discussion on the dev mailing list for this.

[roryqi]

@kelvin9314 @singhpk234 Could u help review this pull request?

[singhpk234]

Thanks for raising this @roryqi

IIUC you are talking of basic header ? if yes it think its pretty common to send the base64 of clientId : secret,

IRC servers such as Apache Polaris already support this : https://github.com/apache/polaris/blob/main/runtime/service/src/main/java/org/apache/polaris/service/auth/internal/service/DefaultOAuth2ApiService.java#L84

other IRC client such as DuckDb already send them :
https://github.com/duckdb/duckdb-iceberg/blob/main/src/catalog/rest/storage/authorization/oauth2.cpp#L163

Nevertheless i would still recommend opening ML Discuss thread !

[singhpk234]

Are you talking of Basic header ?
If yes i think we would need to define it bit better like bearer: https://github.com/roryqi/iceberg/blob/0519d2d1fe3427299d1191b64bcd0376f7f43bf0/open-api/rest-catalog-open-api.yaml#L5265

[roryqi]

Yes, I am talking of Basic header.

OpenAPI has defined Bearer header and Basic header.
You can see
https://swagger.io/docs/specification/v3_0/authentication/bearer-authentication/
https://swagger.io/docs/specification/v3_0/authentication/basic-authentication/

I will add the definition, too.

Thanks for your review.