vue实现大文件切片上传的示例详解

 /**
   * file: 需要切片的文件
   * chunkSize: 每片文件大小，1024*1024=1M
   */
        chunkSlice(file, chunkSize) {
            const chunks = [],
                size = file.size,
                total = Math.ceil(size / chunkSize)
            for (let i = 0; i < size; i += chunkSize) {
                chunks.push({
                    total,
                    blob: file.slice(i, i + chunkSize),
                })
            }
            return chunks
        }

        async handleFile(chunks) {
            const res = []
            for (const item of chunks) {
                const { bytes, md5 } = await this.addMark(item.blob)
                item.blob = bytes
                item.md5 = md5
                res.push(md5)
            }
            return res
        },
        // 使用FileReader读取每一片数据，并生成MD5编码
        async addMark(chunk) {
            return new Promise((resolve, reject) => {
                const reader = new FileReader()
                const spark = new SparkMD5()

                reader.readAsDataURL(chunk)
                reader.onload = function (e) {
                    const bytes = e.target.result
                    spark.append(bytes)

                    const md5 = spark.end()
                    resolve({ bytes, md5 })
                }
            })
        },

        mergeData(chunks) {
            const fileId = this.getUUID()
            const data = []
            for (let i = 0; i < chunks.length; i++) {
                const obj = {
                    fileId,
                    fileData: chunks[i].blob,//每片切片的数据
                    fileIndex: i + 1,//每片数据索引
                    fileTotal: chunks[i].total + '',
                    md5: chunks[i].md5,
                }

                data.push(obj)
            }
            return { data, fileId }
        },

const chunks = chunkSlice(file,1024*1024)
this.handleFile(chunks)
const data = this.mergeData(chunks)

for(let i = 0; i < data.length; i++){
    this.uplload(data[i])
}

    // vue.config.js
    chainWebpack(config) {
        config.module.rule('worker')
            .test(/\.worker\.js$/)
            .use('worker-loader')
            .loader('worker-loader')
            // .options({ inline: 'fallback' })// 这个配置是个坑，不要加
    },

// file.worker.js
import SparkMD5 from 'spark-md5'

const chunkSlice = (file, chunkSize) => {
    const chunks = [],
        size = file.size,
        total = Math.ceil(size / chunkSize)
    for (let i = 0; i < size; i += chunkSize) {
        chunks.push({
            total,
            blob: file.slice(i, i + chunkSize),
        })
    }
    return chunks
}
const handleFile = async (chunks) => {
    const res = []
    for (const item of chunks) {
        const { bytes, md5 } = await addMark(item.blob)
        item.blob = bytes
        item.md5 = md5
        res.push(md5)
    }
    return res
}
const addMark = (chunk) => {
    return new Promise((resolve, reject) => {
        const reader = new FileReader()
        const spark = new SparkMD5()

        reader.readAsDataURL(chunk)
        reader.onload = function (e) {
            const bytes = e.target.result
            spark.append(bytes)

            const md5 = spark.end()
            resolve({ bytes, md5 })
        }
    })
}
const mergeData = (chunks, fileName, options) => {
    const fileId = getUUID() // 这里更好的方式是读整个文件的 MD5
    const data = []
    for (let i = 0; i < chunks.length; i++) {
        const obj = {
            ...options,
            suffix: '.tar.gz',
            fileId,
            fileName,
            fileData: chunks[i].blob,
            fileIndex: i + 1 + '',
            fileTotal: chunks[i].total + '',
            md5: chunks[i].md5,
        }

        data.push(obj)
    }
    return { data, fileId }
}
const getUUID = () => {
    return ([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, (c) =>
        (c ^ (crypto.getRandomValues(new Uint8Array(1))[0] & (15 >> (c / 4)))).toString(16)
    )
}
const dataSlice = (data, step, fileId) => {
    const total = Math.ceil(data.length / step)
    let index = 1
    for (let i = 0; i < data.length; i += step) {
        const params = {
            type: 'workerFile',
            index,
            total,
            fileId,
            data: data.slice(i, i + step),
        }
        self.postMessage(params)
        index++
    }
}
self.addEventListener('error', (event) => {
    console.log('worker error', event)
})

self.addEventListener('message', async (event) => {
    // 确保接受的是我想要的消息  
    if (!event.data.type) return
    if (event.data.type != 'file') return
    console.log('worker success', event)

    const { file, chunkSize } = event.data
    const chunks = chunkSlice(file, chunkSize)
    const allMD5 = await handleFile(chunks)
    console.log(allMD5)
    // 此处 allMD5 可用来做后续的断点续传
    const { data, fileId } = mergeData(chunks, file.name)
    
    // 这里对处理好的数据进行切片，分片传递给主线程，是由于 Web Worker 试图将大量数据复制到主线程中，会导致内存溢出。
    dataSlice(data, 100, fileId)

})

// xxx.vue文件
import Worker from '@/utils/worker/file.worker.js'


const worker = new Worker()
worker.postMessage({ type: 'file', file: this.curFile, chunkSize: 1024 * 1024 })

worker.onerror = (error) => {
    console.log('main error', error)
    worker.terminate()
}

const finalData = []
worker.onmessage = async (event) => {
    console.log('main success', event)
    if (event.data.type != 'workerFile') return

    const fileId = mergeWorkerData(finalData, event.data)
    if (fileId) {
        worker.terminate()

        const status = await stepLoad(finalData, 500)

        if (!status) {
            this.$message.error('文件上传失败')
        } else {
            this.$message.success('文件上传成功')

        }

    }
}

mergeWorkerData = (res, params) => {
    res.push(...params.data)
    return params.index == params.total ? params.fileId : false
}

const stepLoad = async (data, step) => {
    const res = []
    for (let i = 0; i < data.length; i += step) {
        res.push(data.slice(i, i + step))
    }
    for (const item of res) {
        const chunkRes = await Promise.all(item.map((v) => this.$api.upload(v)))
        if (chunkRes.some((v) => v.httpCode != 0)) {
            return false
        }

        const isEnd = chunkRes.filter((v) => v.finish)
        if (isEnd.length) {
            return true
        }
    }
}