使用 JavaScript 的 WebSocket 用戶端-js教程-PHP中文網

WebSocket Client with JavaScript

在本系列的上一篇文章「使用 JavaScript 和 Bun 的 WebSocket」中，我們探討如何初始化能夠處理 HTTP 請求和 WebSocket 連線的伺服器。

我們為 HTTP 請求定義了一條規則，以便在向 / 發出請求時提供 index.html 檔案。 index.html 檔案包含用於與 WebSocket 伺服器建立連線並作為客戶端傳送訊息的用戶端邏輯。

客戶端程式碼

在「WebSocket with JavaScript and Bun」中解釋的伺服器的 fetch 方法中實作了以下程式碼：

  if (url.pathname === "/") 
    return new Response(Bun.file("./index.html"));

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這表示當瀏覽器要求 http://localhost:8080/ 時，index.html 檔案的內容將會傳送到瀏覽器。
HTML 將呈現一個帶有輸入文字和按鈕的簡單表單，並提供作為用戶端連接到 WebSocket 伺服器的邏輯。

<!doctype html>
<html>
    <head>
        <title>WebSocket with Bun and JavaScript</title>
        <script>
            let echo_service;
            append = function (text) {
                document
                    .getElementById("websocket_events")
                    .insertAdjacentHTML("beforeend", "<li>" + text + ";</li>");
            };
            window.onload = function () {
                echo_service = new WebSocket("ws://127.0.0.1:8080/chat");
                echo_service.onmessage = function (event) {
                    append(event.data);
                };
                echo_service.onopen = function () {
                    append("? Connected to WebSocket!");
                };
                echo_service.onclose = function () {
                    append("Connection closed");
                };
                echo_service.onerror = function () {
                    append("Error happens");
                };
            };

            function sendMessage(event) {
                console.log(event);
                let message = document.getElementById("message").value;
                echo_service.send(message);
            }
        </script>
        <link
            rel="stylesheet"
            href="https://cdn.jsdelivr.net/npm/@picocss/pico@2/css/pico.min.css"
        />
    </head>

    <body>
        <main>



<h2>
  
  
  Explaining the client code
</h2>

<p>This code creates a simple <strong>WebSocket client</strong> in a browser to interact with a WebSocket server. Here's a detailed explanation of its components:</p>


<hr>

<h3>
  
  
  The HTML structure
</h3>



<pre class="brush:php;toolbar:false"><!doctype html>
<html>
    <head>
        <title>WebSocket with Bun and JavaScript</title>
    </head>
    <body>
        <main>



<ul>
<li>The input field (<input>
<li>The submit button (<input type="button">): when clicked, it triggers the sendMessage(event) function to send the typed message to the server.

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The messages/events log (

The JavaScript logic

Initializing the WebSocket connection

window.onload = function () {
    echo_service = new WebSocket("ws://127.0.0.1:8080/chat");
    ...
};

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WebSocket("ws://127.0.0.1:8080/chat")：在連接埠 8080 上建立到伺服器 127.0.0.1 的新 WebSocket 連接，特別是 /chat 端點。
變數echo_service保存WebSocket實例，方便與伺服器通訊。

處理 WebSocket 事件

WebSocket 用戶端有四個主要事件處理程序：

onopen（連線建立）

  if (url.pathname === "/") 
    return new Response(Bun.file("./index.html"));

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成功建立與伺服器的連線時會觸發onopen函數。
它會在日誌中附加一條訊息：「？已連接到 WebSocket！」。

onmessage（收到訊息）

<!doctype html>
<html>
    <head>
        <title>WebSocket with Bun and JavaScript</title>
        <script>
            let echo_service;
            append = function (text) {
                document
                    .getElementById("websocket_events")
                    .insertAdjacentHTML("beforeend", "<li>" + text + ";</li>");
            };
            window.onload = function () {
                echo_service = new WebSocket("ws://127.0.0.1:8080/chat");
                echo_service.onmessage = function (event) {
                    append(event.data);
                };
                echo_service.onopen = function () {
                    append("? Connected to WebSocket!");
                };
                echo_service.onclose = function () {
                    append("Connection closed");
                };
                echo_service.onerror = function () {
                    append("Error happens");
                };
            };

            function sendMessage(event) {
                console.log(event);
                let message = document.getElementById("message").value;
                echo_service.send(message);
            }
        </script>
        <link
            rel="stylesheet"
            href="https://cdn.jsdelivr.net/npm/@picocss/pico@2/css/pico.min.css"
        />
    </head>

    <body>
        <main>



<h2>
  
  
  Explaining the client code
</h2>

<p>This code creates a simple <strong>WebSocket client</strong> in a browser to interact with a WebSocket server. Here's a detailed explanation of its components:</p>


<hr>

<h3>
  
  
  The HTML structure
</h3>



<pre class="brush:php;toolbar:false"><!doctype html>
<html>
    <head>
        <title>WebSocket with Bun and JavaScript</title>
    </head>
    <body>
        <main>



<ul>
<li>The input field (<input>
<li>The submit button (<input type="button">): when clicked, it triggers the sendMessage(event) function to send the typed message to the server.

登入後複製