Request-time controller for the read + mutation pipeline.
Every request reaches this plug via the catch-all router. It:
- resolves the target
{schema, relation}from the path +Accept-Profile/Content-Profile(default schema = first ofdb_schemas), - negotiates the response media type against the
Acceptheader, - parses the query string with
Bier.QueryParser, - builds and runs one parameterized JSON query via
Bier.QueryExecutor, - renders the negotiated format (JSON / CSV / singular object /
nulls-stripped / EXPLAIN plan) with a
Content-Range.
Anything that is not a successful Plug.Conn falls through to
Bier.Plugs.FallbackController, which emits the PostgREST error envelope.