DROP EXTENSION IF EXISTS www_fdw CASCADE; CREATE EXTENSION www_fdw; CREATE SERVER www_fdw_server_test FOREIGN DATA WRAPPER www_fdw OPTIONS (uri 'http://localhost:7777', request_serialize_callback 'test_request_serialize_callback', request_serialize_type 'json'); CREATE USER MAPPING FOR current_user SERVER www_fdw_server_test; CREATE FOREIGN TABLE www_fdw_test ( title text, link text, snippet text ) SERVER www_fdw_server_test; CREATE OR REPLACE FUNCTION test_request_serialize_callback(options WWWFdwOptions, quals text, INOUT url text, INOUT post WWWFdwPostParameters) AS $$ BEGIN RAISE DEBUG 'options parameter: %', options; RAISE INFO 'quals parameter: %', quals; RAISE DEBUG 'url parameter: %', url; RAISE DEBUG 'post parameter: %', post; END; $$ LANGUAGE PLPGSQL;