如何启用Fulcro Websockets

Question

关于如何开始使用支点和Websockets，我有一个基本的问题。

我从支点莱茵模板开始。(2)添加了websocket客户机和服务器位。在我的服务器中，我还添加了一个com.fulcrologic.fulcro.networking.websocket-protocols.WSListener来检测WS客户机何时连接。

在WSListener和浏览器的网络控制台之间，我可以看到客户机从未建立WS连接。

• 支点如何进行初始WS连接？
• 在此之后，如何使服务器推送到客户端？

client.cljs

(ns foo.client
  (:require [fulcro.client :as fc]
            [foo.ui.root :as root]
            [fulcro.client.network :as net]
            [fulcro.client.data-fetch :as df]
            [com.fulcrologic.fulcro.networking.websockets :as fws]
            [com.fulcrologic.fulcro.application :as app]))

;; Neither this nor the below ":websocket (fws/fulcro-websocket-remote {})" works
;; (defonce app (app/fulcro-app {:remotes {:remote (fws/fulcro-websocket-remote {})}}))

(defonce SPA (atom nil))

(defn mount [] (reset! SPA (fc/mount @SPA root/Root "app")))
(defn start [] (mount))

(def secured-request-middleware
  ;; The CSRF token is embedded via server_components/html.clj
  (->
    (net/wrap-csrf-token (or js/fulcro_network_csrf_token "TOKEN-NOT-IN-HTML!"))
    (net/wrap-fulcro-request)))

(defn ^:export init []
  (reset! SPA (fc/make-fulcro-client
                {:client-did-mount (fn [foo]
                                     (df/load foo :all-users root/User))
                 ;; This ensures your client can talk to a CSRF-protected server.
                 ;; See middleware.clj to see how the token is embedded into the HTML
                 :networking       {:remote (net/fulcro-http-remote
                                              {:url                "/api"
                                               :request-middleware secured-request-middleware})
                                    :websocket (fws/fulcro-websocket-remote {})}}))
  (start))

middleware.cljs

(defrecord FooWSListener []
  WSListener
  (client-added [this ws-net cid]
    (println (str "Listener for dealing with client added events." [ws-net cid])))
  (client-dropped [this ws-net cid]
    (println (str "listener for dealing with client dropped events." [ws-net cid]))))

(def foo-ws-listener (->FooWSListener))

(def websockets' (atom nil))
(defn query-parser [env query] )

(defstate middleware
  :start
  (let [websockets (fws/start! (fws/make-websockets
                                 query-parser
                                 {:http-server-adapter (get-sch-adapter)
                                  :parser-accepts-env? true
                                  ;; See Sente for CSRF instructions
                                  :sente-options       {:csrf-token-fn nil}}))
        defaults-config (:ring.middleware/defaults-config config)
        legal-origins   (get config :legal-origins #{"localhost"})]

    (fwsp/add-listener websockets foo-ws-listener)
    (reset! websockets' websockets)

    (-> not-found-handler
        (wrap-api "/api")
        (fws/wrap-api websockets)
        server/wrap-transit-params
        server/wrap-transit-response
        (wrap-html-routes)
        (wrap-defaults defaults-config)
        wrap-gzip)))

Answer 1

自支点-websockets 3.1.0以来的websocket连接是通过websocket远程进行的第一次数据传输。

如果要强制连接，可以通过在遥控器上发送任何突变来实现：

(:require [com.fulcrologic.fulcro.mutations :refer [defmutation]
          [com.fulcrologic.fulcro.components :as comp])

(defmutation connect-socket [_]
    (websocket [_] true))

(comment
    ;; trigger it via repl or a button handler
    (comp/transact! foo.client/SPA `[(connect-socket {})]

一旦建立了连接，就可以像这样从服务器上推送：

(:require [com.fulcrologic.fulcro.networking.websocket-protocols :refer [push]])

(let [client-uid (-> @(:connected-uids websockets')
                     :any
                     first)]
    (push websockets' client-uid :foo-topic {:foo "bar"}))

要在客户端上接收该消息，您需要在:push-handler远程上定义一个websocket：

(defn push-handler [{:keys [topic msg] :as data}]
    (log/info "push-handler received: " data))

;; optionally you can listen for websocket state changes
(defn state-callback [before after]
    (log/info "state-callback: " {:before before
                                  :after after}))

(defn ^:export init []


 (reset! SPA (fc/make-fulcro-client
                {:client-did-mount (fn [foo]
                                     (df/load foo :all-users root/User))
                 :remotes          {:remote (net/fulcro-http-remote
                                              {:url                "/api"
                                               :request-middleware secured-request-middleware})
                                    :websocket (fws/fulcro-websocket-remote
                                                   {:push-handler push-handler
                                                    :state-callback state-callback})}}))
  (start))

顺便说一句，由于您使用的是模板提供的mount，您可以使用它来处理服务器上的websockets'：

(defstate websockets'
  :start
  (fws/start! (fws/make-websockets
               query-parser
               {:http-server-adapter (get-sch-adapter)
                :parser-accepts-env? true})))

这样您就可以避免这一行：(reset! websockets' websockets)