JavaScript实现大文件上传的示例代码

const path = require('path')
import axios from 'axios'
import { resolve } from 'path';
import { promised } from 'q';

// 递归调用请求
async function dg(requestMargreList, options, key = 0) {
  let index = key
  const requestList = requestMargreList[key].map(({ formData }) =>
    {
      return multipartUploadUpload(formData, options)
    }
  );
  const resArr = await Promise.all(requestList);
  let boolean = resArr.every(item => item?.data?.status == 'SUCCEED')
  if(boolean){
    index++
    if(index ==  requestMargreList.length) {
      return {uploadFlag: true, msg: '上传切片文件成功' }
    }
    return dg(requestMargreList, options, index)
  } else {
    const res_err = resArr.map(item => item?.data?.status != 'SUCCEED')
    return {uploadFlag: false, msg: '切片文件上传出错，请重新尝试' }
  }

}

//  文件切片
function createFileChunk(file, size){
    let fileChunkList = [];
    let cur = 0;
    while (cur < file.size) {
        fileChunkList.push({file:file.slice(cur, cur + size)})
        cur += size;
    }
    return fileChunkList
}

function calculateHash(fileChunkList, container,options ={}) {
    return new Promise(resolve => {
        // 添加 worker 属性
        container.worker = new Worker("/static/hash.js");
        container.worker.postMessage({ fileChunkList });
        container.worker.onmessage = e => {
            const { percentage, hash } = e.data;
            //  总进度变化
            // hashPercentage = percentage;
            options.showHash(percentage)
            if (hash) {
                resolve(hash);
            }
        };
    })
}

function getMultipartLogId(params){
    return new Promise(resolve =>{
        axios.post('api/multipartUploadInit',params)
        .then(res=>{
          resolve(res)
        })
    })
}

let globalPercentage = 0;

function multipartUploadUpload(formData, options) {

  return  axios.post('api/multipartUploadUpload',formData,{
        onUploadProgress: function (upEvent) {   //  文件上传总进度
            let percentage = ((options.size * (formData.get('chunkIndex')- 1) + upEvent.loaded) / options.fileSize)*100
            //options.size为分片后每片的大小 options.fileSize为文件总大小 percentage为计算后总进度
            if(percentage > globalPercentage){
              globalPercentage = percentage;
            }
            if(globalPercentage>100) globalPercentage = 100;
            options.showFileProgress(globalPercentage)
        }
    })
}


async function uploadChunks(fileChunkList, options) {
    let reqMargeArr = [], reqSize = 3, uploadResObj = {};
    let reqBeforeList = fileChunkList.map(({ multipartLogId,hash,file,fileName,chunkIndex }) => {
      const formData = new FormData();
      formData.append("multipartLogId", multipartLogId);
      formData.append("hash", hash);
      formData.append("file", file);
      formData.append("fileName", fileName);
      formData.append("chunkIndex", chunkIndex);
      return { formData };
    })

    if(reqBeforeList.length > reqSize) {
      for (let i = 0; i < reqBeforeList.length; i += reqSize) {
        reqMargeArr.push(reqBeforeList.slice(i, i + reqSize))
      }
      const {uploadFlag, msg} = await dg(reqMargeArr, options,)
      uploadResObj = { uploadFlag, msg}
    } else {
      const requestList = reqBeforeList.map(({ formData }) =>
        {
          return multipartUploadUpload(formData, options)
        });
      let resArr = await Promise.all(requestList);
      const uploadFlag = resArr.every(item => item?.data?.status == 'SUCCEED')
      uploadResObj = { uploadFlag, msg: uploadResObj.uploadFlag?'上传切片文件成功':'切片文件上传出错，请重新尝试'}
    }
    if(uploadResObj.uploadFlag) {
      // completeFunc函数中有回调接口判断是否合并成功
      setTimeout(()=>{
        completeFunc(fileChunkList[0].multipartLogId,options)
      }, 1000)
    } else {
      return uploadResObj
    }
}

function completeFunc(multipartLogId, options) {

  return axios.post('api/multipartUploadComplete',{multipartLogId})
      .then(res=>{
        options.completeFunc(res)
      })

}

async function bigFileUpload(file, options={},fileOptions) {
    let container = {}
    let fileChunkList = createFileChunk(file,options?.size);
    const fileHash = await calculateHash(fileChunkList, container,options);

    fileOptions.hash = fileHash
    const upFileParams = await getMultipartLogId(fileOptions)
    //  删除已上传的文件片
    let fileChunkListArr = [];
    let percentage = 0;
    if(upFileParams.data.status == 'SUCCEED'){
        let chunkIndexs = upFileParams?.data?.data?.chunkIndexs;
        if(chunkIndexs?.length>0){
            fileChunkList.map(({ file },index) => {

                if(!chunkIndexs.includes(index+1)){
                    fileChunkListArr.push({
                        multipartLogId: upFileParams.data.data.multipartLogId,
                        chunkIndex: index + 1,
                        hash: fileHash,
                        file: file,
                        fileName: fileOptions.fileName,
                    })
                }
            });
            percentage = percentage + (chunkIndexs.length * fileOptions.chunkSize / options.fileSize)*100
            options.showFileProgress(percentage)

        } else {
            fileChunkList.map(({ file },index) => {
                fileChunkListArr.push({
                        multipartLogId: upFileParams.data.data.multipartLogId,
                        chunkIndex: index + 1,
                        hash: fileHash,
                        file: file,
                        fileName: fileOptions.fileName,
                    })
                }
            );
        }
        if(fileChunkListArr.length>0){
          //  上传文件切片
          const uploadRes = await uploadChunks(fileChunkListArr, options,percentage)
          return uploadRes
        } else {
          completeFunc(upFileParams.data.data.multipartLogId,options)
        }

    } else {
      return { uplodFlag: false, msg: upFileParams.data.extMessage }
    }
}

export default bigFileUpload

import bigFileUpload from './components/bigFileUpload'
//  大文件上传
        //  分片大小 bigFileUpload
 let fileParams = {
          size: bigSize, // 切片大小
          fileSize: fileTem.size,
          showHash: this.showHash,
          showFileProgress: this.showFileProgress,
          completeFunc: this.completeFunc,
        }
        this.fileOptions = fileOptions
        const res = await bigFileUpload(fileTem, fileParams,fileOptions)
console.log("=====big up res========", res)
        if(res && !res.uplodFlag) {
          _this.$Notice.error({
            title: '提醒',
            desc: res.msg
          })
          return
        }