Bier.CustomMedia (bier v0.1.0)

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PostgREST custom media-type handlers.

A custom media type is a DOMAIN whose name is the MIME string; a handler is an aggregate whose transition-state type is that domain. The aggregate's first argument is the relation (or anyelement) it applies to. A function returning a media-type domain is the "Any"/per-result handler.

When a request's Accept matches a handler for the target relation/RPC, the handler runs in SQL and its (already-serialized) output becomes the response body, with the domain's MIME as the Content-Type.

Summary

Functions

maybe_relation(conn, config, relation)

Try to satisfy a relation GET via a custom media handler aggregate keyed on the relation. Returns a Plug.Conn if handled, or :no_handler.

maybe_rpc(conn, config, fn_def)

Try to satisfy an RPC via a custom handler: either the function itself returns a media-type domain (the "Any"/scalar handler), or an anyelement aggregate applies to the function's result. Returns a Plug.Conn or :no_handler.

Functions

maybe_relation(conn, config, relation)

Try to satisfy a relation GET via a custom media handler aggregate keyed on the relation. Returns a Plug.Conn if handled, or :no_handler.

lookupHandler gates BOTH of its relation-keyed probes behind when' defaultSelect (Plan/Negotiate.hs#L76-L77): a relation-scoped handler aggregates the relation's whole ROW type, so it can only serve a request that projects the default select list. An explicit ?select= drops it out of negotiation entirely and the request falls back to the built-in producers — which, for a media type none of them emits, is a 406 (case 1646).

maybe_rpc(conn, config, fn_def)

Try to satisfy an RPC via a custom handler: either the function itself returns a media-type domain (the "Any"/scalar handler), or an anyelement aggregate applies to the function's result. Returns a Plug.Conn or :no_handler.