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web worker的基本使用案例

网友: 文章列表 2024-03-21 16:11:25

web worker的基本使用案例

  1. 文件目录如下

在这里插入图片描述

  1. 代码按照顺序分别如下

    • webworker.html

      <!DOCTYPE html>
<html lang="en"><head><meta charset="utf-8" /><meta http-equiv="X-UA-Compatible" content="IE=edge" /><meta name="viewport" content="width=device-width" /><title>Web Workers basic example</title><link rel="stylesheet" href="./css/style.css" /></head><body><h1>Web<br />Workers<br />basic<br />example</h1><div class="controls" tabindex="0"><form><div><label for="number1">上传: </label><input type="file" id="file-upload" /></div><div><label for="number1">数字1: </label><input type="text" id="number1" value="0" /></div><div><label for="number2">数字2: </label><input type="text" id="number2" value="0" /></div><div><button type="button">计算hash</button></div></form><p class="result">结果: 0</p></div><script src="./js/main.js"></script></body>
</html>

    • style.css

      html {background-color: #7d2663;font-family: sans-serif;
}h1 {margin: 0;font-size: 20vmin;letter-spacing: -0.2rem;position: absolute;top: 0;z-index: -1;
}p {margin: 0;
}.controls {padding: 4vw;width: 75%;margin: 10vw auto;background-color: rgba(255, 255, 255, 0.7);border: 5px solid black;opacity: 1;transition: 1s all;
}.controls:hover,
.controls:focus {opacity: 1;
}.controls label,
.controls p,
.controls input {font-size: 3vw;
}.controls div {padding-bottom: 1rem;
}

    • main.js

      const first = document.querySelector('#number1');
const second = document.querySelector('#number2');
const fileUplaod = document.querySelector('#file-upload');const result = document.querySelector('.result');
const CHUNKS_SIZE = 1 * 1024 * 1024;if (window.Worker) {const myWorker = new Worker('./js/webworker.js', { name: 1 });// 文件分片const filefragment = (file, size = CHUNKS_SIZE) => {let curr = 0;const chunks = [];while (curr < file.size) {chunks.push({ index: curr, file: file.slice(curr, curr + size) });curr += size;}return chunks;};// 计算hashconst calcHash = (chunks) => {return new Promise((resolve, reject) => {myWorker.postMessage({ chunks });myWorker.onmessage = (e) => {const { hash } = e.data;if (hash) {resolve(hash);} else {reject();}};});};first.onchange = function () {myWorker.postMessage([first.value, second.value]);console.log('数字1发生了变化');};second.onchange = function () {myWorker.postMessage([first.value, second.value]);console.log('数字2发生了变化');};fileUplaod.onchange = async function (e) {const file = e.target.files[0];if (!file) return;const chunks = filefragment(file);const hash = await calcHash(chunks);console.log(hash);};myWorker.onmessage = function (e) {result.textContent = e.data;console.log('接收返回结果');};
} else {console.log('您的浏览器不支持webworker');
}

    • spak-md5.js由于代码太长,这边提供下载链接

      // https://www.bootcdn.cn/spark-md5/

    • webworker.js

      self.importScripts('./spark-md5.js');self.onmessage = function (e) {const { chunks } = e.data;const spark = new self.SparkMD5.ArrayBuffer();let count = 0;const loadNext = (index) => {const reader = new FileReader();reader.readAsArrayBuffer(chunks[index].file);reader.onload = (e) => {count++;spark.append(e.target.result);if (count == chunks.length) {self.postMessage({hash: spark.end(),});} else {loadNext(count);}};};loadNext(0);
};

  2. 大致的使用方法如上,如果想更详细的了解的话,请转至MDN

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