如何启用Fulcro Websockets

Question

我有一个关于如何开始使用Fulcoro和Websockets的基本问题。

i( 我从富尔克罗莱因模板开始。ii(然后添加websocket客户端和服务器位。iii(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客户端何时正在连接。

在WSListener和浏览器的网络控制台之间，我可以看到客户端从未进行WS连接。

• Fulcro是如何建立初始WS连接的
• 之后，我如何让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))

中间件.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

由于fulcro websockets 3.1.0，websocket连接是通过websocket remote在第一次数据传输时进行的。

如果你想强制连接，你可以通过远程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 {})]

一旦你建立了连接，你就可以从服务器上进行推送，如下所示：

(: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，您需要在websocketremote:上定义一个:push-handler

(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，您可以使用它在服务器上处理websockets'：

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

这样你就可以避开这条线：(reset! websockets' websockets)