Postgres listen/notify in Clojure using http://impossibl.github.io/pgjdbc-ng/

core.clj

; Postgres listen/notify in Clojure using http://impossibl.github.io/pgjdbc-ng/

; in project.clj dependencies
; [com.impossibl.pgjdbc-ng/pgjdbc-ng "0.5"]


(ns pglisten.core
  (:import [com.impossibl.postgres.jdbc PGDataSource]
           [com.impossibl.postgres.api.jdbc PGNotificationListener]))


(def datasource (doto (PGDataSource.)
                      (.setHost     "localhost") ; todo move into
                      (.setPort     5432)
                      (.setDatabase "listenpg_db")
                      (.setUser     "listenpg_user")
                      (.setPassword "password")))


; create a listener that triggers when a message is received
(def listener
  (reify PGNotificationListener
    (^void notification [this ^int processId ^String channelName ^String payload]
           (println "msg: " payload) )))


; setup a connection with the listener
(def connection
  (doto (.getConnection datasource)
        (.addNotificationListener listener)))


; begin listening to a channel
(doto (.createStatement connection)
      (.execute "LISTEN mymessages;")
      (.close))




; trigger message using psql, should print to console in clojure app.
; select pg_notify('mymessages', 'hello...');