Long running WAMP RPC call with progress status events

browser-output.txt

Long Run Button clicked
WAMP client initialized 
WAMP connected 1377136104011-1 
status:long-run RECEIVED 0 
status:long-run RECEIVED 1 
status:long-run RECEIVED 2 
status:long-run RECEIVED 3
status:long-run RECEIVED 4 
status:long-run RECEIVED 5 
status:long-run RECEIVED 6 
status:long-run RECEIVED 7 
status:long-run RECEIVED 8 
status:long-run RECEIVED 9 
rpc:long-run RECEIVED true true 

client.cljs

(ns clj-wamp-cljs.rpcstatus
  (:require
    [clj-wamp.client :as wamp :refer [wamp-handler]]
    [clojure.browser.event :as event]))

(declare
  add-btn-listener
  trigger-wamp-call
  on-wamp-open
  on-wamp-close
  on-wamp-event
  call-long-run)

(def long-run-rpc-uri    "http://myapp/rpc#long-run")
(def long-run-status-uri "http://myapp/status#long-run")

; On page load, init
(defn ^:export init []
  (add-btn-listener))

(defn add-btn-listener []
  ; Button click triggers the websocket connection and rpc call.
  ; Only listen once so multiple clicks do not re-trigger call.
  (let [long-run-btn (.getElementById js/document "long-run-btn")]
    (event/listen-once long-run-btn "click" trigger-wamp-call)))

(defn trigger-wamp-call []
  (.log js/console "Long Run Button clicked")
  (if-let [ws (wamp-handler "ws://localhost:8080/ws"
                {:on-open  on-wamp-open
                 :on-close on-wamp-close
                 :on-event on-wamp-event})]
    (.log js/console "WAMP client initialized")
    (.log js/console "WAMP client init failed")))

(defn on-wamp-open [ws sess-id]
  (.log js/console "WAMP connected" sess-id)
  ; Subscribe to status channel
  (wamp/subscribe! ws long-run-status-uri)
  ; Issue the RPC request
  (call-long-run ws))

(defn call-long-run [ws]
  (wamp/rpc! ws long-run-rpc-uri ["test"]
    (fn [ws success? result]
      (.log js/console "rpc:long-run RECEIVED" success? (pr-str result))
      ; Stop websocket now that we have the result
      (wamp/close! ws))))

(defn on-wamp-event [ws topic event]
  ; Listen for any pubsub status events
  (cond
    (= topic long-run-status-uri)
    (.log js/console "status:long-run RECEIVED" (pr-str event))))

(defn on-wamp-close []
  (.log js/console "WAMP disconnected")
  (add-btn-listener))

server-output.txt

2013-08-21 21:48:24,025 TRACE clj-wamp.server: Sending data: (0 1377136104011-1 1 clj-wamp/1.1.0-SNAPSHOT)
2013-08-21 21:48:24,026 INFO  clj-wamp-cljs.websocket: WAMP client connected [ 1377136104011-1 ]
2013-08-21 21:48:24,031 TRACE clj-wamp.server: Data received: [5,"http://myapp/status#long-run"]
2013-08-21 21:48:24,036 TRACE clj-wamp.server: Data received: [2,"0.ywh61cuxx3g3z0k9","http://myapp/rpc#long-run","test"]
2013-08-21 21:48:24,037 INFO  clj-wamp-cljs.websocket: WAMP call: 1377136104011-1 http://myapp/rpc#long-run 0.ywh61cuxx3g3z0k9 (test)
2013-08-21 21:48:24,038 INFO  clj-wamp-cljs.websocket: Long Run RPC called test
2013-08-21 21:48:25,040 TRACE clj-wamp.server: Sending data: (8 http://myapp/status#long-run 0)
2013-08-21 21:48:26,045 TRACE clj-wamp.server: Sending data: (8 http://myapp/status#long-run 1)
2013-08-21 21:48:27,046 TRACE clj-wamp.server: Sending data: (8 http://myapp/status#long-run 2)
2013-08-21 21:48:28,047 TRACE clj-wamp.server: Sending data: (8 http://myapp/status#long-run 3)
2013-08-21 21:48:29,049 TRACE clj-wamp.server: Sending data: (8 http://myapp/status#long-run 4)
2013-08-21 21:48:30,050 TRACE clj-wamp.server: Sending data: (8 http://myapp/status#long-run 5)
2013-08-21 21:48:31,051 TRACE clj-wamp.server: Sending data: (8 http://myapp/status#long-run 6)
2013-08-21 21:48:32,052 TRACE clj-wamp.server: Sending data: (8 http://myapp/status#long-run 7)
2013-08-21 21:48:33,054 TRACE clj-wamp.server: Sending data: (8 http://myapp/status#long-run 8)
2013-08-21 21:48:34,054 TRACE clj-wamp.server: Sending data: (8 http://myapp/status#long-run 9)
2013-08-21 21:48:34,055 TRACE clj-wamp.server: Sending data: (3 0.ywh61cuxx3g3z0k9 true)
2013-08-21 21:48:34,062 INFO  clj-wamp-cljs.websocket: WAMP client disconnected [ 1377136104011-1 ]  :normal

server.cljs

(ns clj-wamp-example
  (:require [org.httpkit.server :as http-kit]
            [clj-wamp.server :as wamp]
            [clojure.tools.logging :as log]))

(def long-run-rpc-uri    "http://myapp/rpc#long-run")
(def long-run-status-uri "http://myapp/status#long-run")

(defn long-run [data]
  (log/info "Long Run RPC called" data)
  (doseq [i (range 10)]
    (Thread/sleep 1000)
    ; Only send status to the client who called
    (wamp/emit-event! long-run-status-uri i [wamp/*call-sess-id*]))
  {:result true})

(defn my-wamp-handler
  "Returns a http-kit websocket handler with wamp subprotocol"
  [request]
  (http-kit/with-channel request channel
    (wamp/http-kit-handler channel
      ; Expose RPC and PubSub topics
      {:on-call        {long-run-rpc-uri    long-run-rpc}}
       :on-subscribe   {long-run-status-uri true} 
       :on-publish     {long-run-status-uri true}})))

(http-kit/run-server my-wamp-handler {:port 8080})

A simple WAMP server with a long running RPC call long-run.
The call will simulate progress status by looping/sleeping and sending a status event to a PubSub channel. When done looping the result is returned.

In the client, a button click will start a WAMP websocket connection. Immediately upon open it will subscribe to the status PubSub channel and issue the long running RPC call. A PubSub event listener on-wamp-event receives all of the progress status events.

On completion of the RPC call, the client closes the WAMP connection and the button listener is set again.