More advanced HTTP caching/concurrency feature that builds on ETag that's already implemented. This is adding features when serving an existing static file and the request includes If-Match and it does not match the current ETag (including list syntax), it should respond 412 Precondition Failed. It should include ETag: , the usual Cache-Control and if If-Match matches (or is *), proceed with the existing If-None-Match → 304 logic and normal 200 responses.
More advanced HTTP caching/concurrency feature that builds on ETag that's already implemented. This is adding features when serving an existing static file and the request includes If-Match and it does not match the current ETag (including list syntax), it should respond 412 Precondition Failed. It should include ETag: , the usual Cache-Control and if If-Match matches (or is *), proceed with the existing If-None-Match → 304 logic and normal 200 responses.