文件上傳到oss代碼片斷

import axios from '@/global/axios.js'

let expire = 0
let accessKeyId
let policy
let signature
let host
let callback

// 獲取policy
function getPolicy (file, filePath, changeSize, callbackImg) {
    // 能夠判斷當前expire是否超過了當前時間,若是超過了當前時間,就從新取一下.3s 作爲緩衝
    let now = new Date().getTime() / 1000
    if (expire < now + 3) {
        axios.get('/api-oss/oss/policy')
            .then((result) => {
            let res = result.data
            if (res.code === 2000) {
            expire = res.data.expire
            accessKeyId = res.data.accessKeyId
            policy = res.data.policy
            signature = res.data.signature
            host = res.data.host
            callback = res.data.callback

            if (file.type.split('/')[0] === 'image') {
                imgChange(file, filePath, changeSize, callbackImg)
            } else {
                callbackOss(file, filePath, callbackImg)
            }
        }
    })
    } else {
        if (file.type.split('/')[0] === 'image') {
            imgChange(file, filePath, changeSize, callbackImg)
        } else {
            callbackOss(file, filePath, callbackImg)
        }
    }
}

// 上傳文件到oss
function callbackOss (fileObj, filePath, callbackImg) {
    let formData = new FormData()
    formData.append('key', filePath)
    formData.append('policy', policy)
    formData.append('OSSAccessKeyId', accessKeyId)
    formData.append('success_action_status', '200') // 讓服務端返回200,否則，默認會返回204
    formData.append('callback', callback)
    formData.append('signature', signature)
    formData.append('file', fileObj)

    let config = {
        headers: {
            'Content-Type': 'multipart/form-data'
        }
    }
    axios.post(host, formData, config)
        .then(function (result) {
            uploadOss.imgPath = host + '/' + result.data.data.filename
            if (callbackImg) {
                callbackImg()
            }
        })
}

// 圖片壓縮函數
function imgChange (file, basePath, changeSize, callbackImg) {
    let changeSizeDefault = changeSize || '1'
    let reader = new FileReader()
    let img = new Image()
    reader.readAsDataURL(file)
    reader.onload = function (e) {
        img.src = e.target.result
    }
    let canvas = document.createElement('canvas')
    let context = canvas.getContext('2d')
    img.onload = function () {
        // 圖片原生尺寸
        let originWidth = this.width
        let originHeight = this.height

        canvas.width = originWidth
        canvas.height = originHeight

        context.clearRect(0, 0, originWidth, originHeight)
        context.drawImage(img, 0, 0, originWidth, originHeight)
        canvas.toBlob(function (blob) {
            callbackOss(blob, basePath, callbackImg)
        }, file.type || 'image/png', changeSizeDefault)
    }
}

/**
 * 獲取文件路徑
 * @method getFilePath
 * @param {object} file 文件對象
 * @param {string} basePath 基礎路徑
 * @return {string} filePath 文件路徑
 */
function getFilePath (file, basePath) {
    let filePath = ''
    let fileExtension = getBaseExtension(file.type)
    let filename = getUuid() + '.' + fileExtension
    let basePathRep = replace(basePath)
    if (basePathRep === '') {
        filePath = filename
    } else {
        filePath = basePathRep + '/' + filename
    }
    return filePath
}

// 獲取文件擴展名
function getBaseExtension (fileType) {
    if (fileType === 'video/x-ms-wmv') {
        fileType = 'video/wmv' // 對wmv格式的視頻文件進行處理
    }
    return fileType.split('/')[1]
}

/**
 * 生成36位 uuid
 * @returns {string} uuid
 */
function getUuid () {
    let s = []
    var hexDigits = '0123456789abcdefhijkmnprstwxyz'
    for (let i = 0; i < 36; i++) {
        s[i] = hexDigits.substr(Math.floor(Math.random() * 0x10), 1)
    }
    return s.join('')
}

/**
 * 格式化
 * @param str 要格式化的字符串
 * @returns {string}
 */
function replace (str) {
    let replacedStr = str
    let length = replacedStr.length
    if (str.indexOf('/') === 0) {
        if (length === 1) {
            replacedStr = ''
        } else {
            replacedStr = str.substring(1, length)
        }
        length -= 1
    }
    if (length - 1 === replacedStr.lastIndexOf('/')) {
        replacedStr = replacedStr.substring(0, length - 1)
    }
    return replacedStr
}

// 對外接口對象封裝
let uploadOss = {
    imgPath: '',
    // file文件上傳
    fileInit: function (file, basePath, changeSize, callbackImg) {
        let filePath = getFilePath(file, basePath)
        getPolicy(file, filePath, changeSize, callbackImg)
    }
}

export default uploadOss