Handling domains created as custom types or other domains

[laurenceisla]

Right now, a domain created as a data type defined in pg_catalog returns the name of the base type. No problem there, since:

create domain mydomain as int;

will be shown in OpenAPI as an integer. The problem starts when the domain is created as a custom type or as another domain. Then, postgrest-openapi treats it as a string instead of the schema defined by the base type.

[laurenceisla]

The recursive CTE to get the base_types of return types from functions could be useful here:

postgrest-openapi/sql/postgrest.sql

Lines 180 to 203 in 95bdd26

	-- Recursively get the base types of domains
	WITH
	base_types AS (
	WITH RECURSIVE
	recurse AS (
	SELECT
	oid,
	typbasetype,
	COALESCE(NULLIF(typbasetype, 0), oid) AS base
	FROM pg_type
	UNION
	SELECT
	t.oid,
	b.typbasetype,
	COALESCE(NULLIF(b.typbasetype, 0), b.oid) AS base
	FROM recurse t
	JOIN pg_type b ON t.typbasetype = b.oid
	)
	SELECT
	oid,
	base
	FROM recurse
	WHERE typbasetype = 0
	),