功能介绍：nodejs文件的分片与合并上传介绍！在JavaScript中，FIle对象是' Blob '对象的子类，该对象包含一个重要的方法slice，通过该方法我们可以这样分割二进制文件。
代码如下：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<script src="https://cdn.bootcdn.net/ajax/libs/axios/0.24.0/axios.min.js"></script>
</head>
<body>
<input type="file" multiple="multiple" id="fileInput" />
<button onclick="SliceUpload()">上传</button>
<script>
function SliceUpload() {
const file = document.getElementById('fileInput').files[0]
if (!file) return
// 文件分片
let size = 1024 * 50; //50KB 50KB Section size
let fileChunks = [];
let index = 0; //Section num
for (let cur = 0; cur < file.size; cur += size) {
fileChunks.push({
hash: index++,
chunk: file.slice(cur, cur + size),
});
}
// 上传分片
const uploadList = fileChunks.map((item, index) => {
let formData = new FormData();
formData.append("filename", file.name);
formData.append("hash", item.hash);
formData.append("chunk", item.chunk);
return axios({
method: "post",
url: "/upload",
data: formData,
});
});
await Promise.all(uploadList);
// 所有分片上传完成，通知服务器合并分片
await axios({
method: "get",
url: "/merge",
params: {
filename: file.name,
},
});
console.log("Upload to complete");
}
</script>
</body>
</html>
结合Promise.race()控制并发
// 加入并发控制
async function SliceUpload() {
const file = document.getElementById('fileInput').files[0]
if (!file) return
// 文件分片
let size = 1024 * 50; //50KB 50KB Section size
let fileChunks = [];
let index = 0; //Section num
for (let cur = 0; cur < file.size; cur += size) {
fileChunks.push({
hash: index++,
chunk: file.slice(cur, cur + size),
});
}
let pool = []; //Concurrent pool
let max = 3; //Maximum concurrency
for (let i = 0; i < fileChunks.length; i++) {
let item = fileChunks[i];
let formData = new FormData();
formData.append("filename", file.name);
formData.append("hash", item.hash);
formData.append("chunk", item.chunk);
// 上传分片
let task = axios({
method: "post",
url: "/upload",
data: formData,
});
task.then(() => {
// 从并发池中移除已经完成的请求
let index = pool.findIndex((t) => t === task);
pool.splice(index);
});
// 把请求放入并发池中，如果已经达到最大并发量
pool.push(task);
if (pool.length === max) {
//All requests are requested complete
await Promise.race(pool);
}
}
// 所有分片上传完成，通知服务器合并分片
await axios({
method: "get",
url: "/merge",
params: {
filename: file.name,
},
});
console.log("Upload to complete");
}
使代码可复用
function SliceUpload() {
const file = document.getElementById('fileInput').files[0]
if (!file) return
// 文件分片
let size = 1024 * 50; // 分片大小设置
let fileChunks = [];
let index = 0; // 分片序号
for (let cur = 0; cur < file.size; cur += size) {
fileChunks.push({
hash: index++,
chunk: file.slice(cur, cur + size),
});
}
const uploadFileChunks = async function(list){
if(list.length === 0){
// 所有分片上传完成，通知如无
await axios({
method: 'get',
url: '/merge',
params: {
filename: file.name
}
});
console.log('Upload to complete')
return
}
let pool = [] // 并发池
let max = 3 // 最大并发数
let finish = 0 // 完成数量
let failList = [] // 失败列表
for(let i=0;i{
// 从并发池中移除已经完成的请求
let index = pool.findIndex(t=> t===task)
pool.splice(index)
}).catch(()=>{
failList.push(item)
}).finally(()=>{
finish++
// 如果有失败的重新上传
if(finish===list.length){
uploadFileChunks(failList)
}
})
pool.push(task)
if(pool.length === max){
await Promise.race(pool)
}
}
}
uploadFileChunks(fileChunks)
}
服务端接口实现
const express = require('express') const multiparty = require('multiparty') const fs = require('fs') const path = require('path') const { Buffer } = require('buffer') // file path const STATIC_FILES = path.join(__dirname, './static/files') // Temporary path to upload files const STATIC_TEMPORARY = path.join(__dirname, './static/temporary') const server = express() // Static file hosting server.use(express.static(path.join(__dirname, './dist'))) // Interface for uploading slices server.post('/upload', (req, res) => { const form = new multiparty.Form(); form.parse(req, function(err, fields, files) { let filename = fields.filename[0] let hash = fields.hash[0] let chunk = files.chunk[0] let dir = `${STATIC_TEMPORARY}/${filename}` // console.log(filename, hash, chunk) try { if (!fs.existsSync(dir)) fs.mkdirSync(dir) const buffer = fs.readFileSync(chunk.path) const ws = fs.createWriteStream(`${dir}/${hash}`) ws.write(buffer) ws.close() res.send(`${filename}-${hash} Section uploaded successfully`) } catch (error) { console.error(error) res.status(500).send(`${filename}-${hash} Section uploading failed`) } }) }) //Merged slice interface server.get('/merge', async (req, res) => { const { filename } = req.query try { let len = 0 const bufferList = fs.readdirSync(`${STATIC_TEMPORARY}/${filename}`).map((hash,index) => { const buffer = fs.readFileSync(`${STATIC_TEMPORARY}/${filename}/${index}`) len += buffer.length return buffer }); //Merge files const buffer = Buffer.concat(bufferList, len); const ws = fs.createWriteStream(`${STATIC_FILES}/${filename}`) ws.write(buffer); ws.close(); res.send(`Section merge completed`); } catch (error) { console.error(error); } }) server.listen(3000, _ => { console.log('http://localhost:3000/') })
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