Event emitter for postgresql listen function

notify_event

-- Function: notify_event()

-- DROP FUNCTION notify_event();

CREATE OR REPLACE FUNCTION notify_event()
  RETURNS trigger AS
$BODY$

    DECLARE 
        data json;
        notification json;
    
    BEGIN
    
        -- Convert the old or new row to JSON, based on the kind of action.
        -- Action = DELETE?             -> OLD row
        -- Action = INSERT or UPDATE?   -> NEW row
        IF (TG_OP = 'DELETE') THEN
            data = row_to_json(OLD);
        ELSE
            data = row_to_json(NEW);
        END IF;
        
        -- Contruct the notification as a JSON string.
       
        
                        
        -- Execute pg_notify(channel, notification)
        PERFORM pg_notify('events_'||TG_TABLE_NAME,'{"action":"'||TG_OP||'","data":'||data::text||'}');
       
        -- Result is ignored since this is an AFTER trigger
        RETURN NULL; 
    END;
    
$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;
ALTER FUNCTION notify_event()
  OWNER TO merlin;

trigger

-- Trigger: ally_target_notify_event on ally_target

-- DROP TRIGGER ally_target_notify_event ON ally_target;

CREATE TRIGGER ally_target_notify_event
  AFTER INSERT OR UPDATE OR DELETE
  ON ally_target
  FOR EACH ROW
  EXECUTE PROCEDURE notify_event();