index.js

const debug = require('debug')('qcloud-sdk[CosUploader]')
const multiparty = require('multiparty')
const readChunk = require('read-chunk')
const shortid = require('shortid')
const fs = require('fs')
const fileType = require('file-type')
const CosSdk = require('cos-nodejs-sdk-v5')
const ERRORS = require('../constants').ERRORS
const config = require('../../config')

const regionMap = {
    'ap-beijing-1': 'tj',
    'ap-beijing': 'bj',
    'ap-shanghai': 'sh',
    'ap-guangzhou': 'gz',
    'ap-chengdu': 'cd',
    'ap-singapore': 'sgp',
    'ap-hongkong': 'hk',
    'na-toronto': 'ca',
    'eu-frankfurt': 'ger'
}

/**
 * 对象上传 API
 * @param {express request} req
 * @return {Promise} 上传任务的 Promise 对象
 */
module.exports = (req) => {
    // 初始化 sdk
    const cos = new CosSdk({
        AppId: config.qcloudAppId,
        SecretId: config.qcloudSecretId,
        SecretKey: config.qcloudSecretKey,
        Domain: `http://${config.cos.fileBucket}-${config.qcloudAppId}.cos.${config.cos.region}.myqcloud.com/`
    })

    const maxSize = config.cos.maxSize ? config.cos.maxSize : 10
    const fieldName = config.cos.fieldName ? config.cos.fieldName : 'file'

    debug('Cos sdk init finished')

    // 初始化 multiparty
    const form = new multiparty.Form({
        encoding: 'utf8',
        maxFilesSize: maxSize * 1024 * 1024,
        autoFiles: true,
        uploadDir: '/tmp'
    })

    return new Promise((resolve, reject) => {
        // 从 req 读取文件
        form.parse(req, (err, fields = {}, files = {}) => {
            err ? reject(err) : resolve({fields, files})
        })
    }).then(({files}) => {
        if (!(fieldName in files)) {
            debug('%s: 请求中没有名称为 %s 的field，请检查请求或 SDK 初始化配置', ERRORS.ERR_REQUEST_LOST_FIELD, fieldName)
            throw new Error(ERRORS.ERR_REQUEST_LOST_FIELD)
        }

        const imageFile = files.file[0]

        /**
         * 判断文件类型
         * 为保证安全默认支持的文件类型有：
         * 图片：jpg jpg2000 git bmp png
         * 音频：mp3 m4a
         * 文件：pdf
         */
        const buffer = readChunk.sync(imageFile.path, 0, 262)
        let resultType = fileType(buffer)

        // 如果无法获取文件的 MIME TYPE 就取 headers 里面的 content-type
        if (!resultType && imageFile.headers && imageFile.headers['content-type']) {
            const tmpPathArr = imageFile.path ? imageFile.path.split('.') : []
            const extName = tmpPathArr.length > 0 ? tmpPathArr[tmpPathArr.length - 1] : ''
            resultType = {
                mime: imageFile.headers['content-type'],
                ext: extName
            }
        }

        const allowMimeTypes = config.cos.mimetypes
            ? config.cos.mimetypes
            : ['image/jpeg', 'image/jp2', 'image/jpm', 'image/jpx', 'image/gif', 'image/bmp', 'image/png', 'audio/mpeg', 'audio/mp3', 'audio/m4a', 'application/pdf']
        if (!resultType || !allowMimeTypes.includes(resultType.mime)) {
            debug('%s: 不支持类型的文件', ERRORS.ERR_UNSUPPORT_FILE_TYPE, imageFile)
            throw new Error(ERRORS.ERR_UNSUPPORT_FILE_TYPE)
        }

        // 生成上传参数
        const srcpath = imageFile.path
        const imgKey = `${Date.now()}-${shortid.generate()}` + (resultType.ext ? `.${resultType.ext}` : '')
        const uploadFolder = config.cos.uploadFolder ? config.cos.uploadFolder + '/' : ''
        const params = {
            Bucket: config.cos.fileBucket,
            Region: config.cos.region,
            Key: `${uploadFolder}${imgKey}`,
            Body: fs.createReadStream(srcpath),
            ContentLength: imageFile.size
        }

        return new Promise((resolve, reject) => {
            // 检查 bucket 是否存在，不存在则创建 bucket
            cos.getService(params, (err, data) => {
                if (err) {
                    reject(err)
                    // remove uploaded file
                    fs.unlink(srcpath, () => {})
                    return
                }

                // 检查提供的 Bucket 是否存在
                const hasBucket = data.Buckets && data.Buckets.reduce((pre, cur) => {
                    return pre || cur.Name === `${config.cos.fileBucket}-${config.qcloudAppId}`
                }, false)

                if (data.Buckets && !hasBucket) {
                    cos.putBucket({
                        Bucket: config.cos.fileBucket,
                        Region: config.cos.region,
                        ACL: 'public-read'
                    }, function (err, data) {
                        if (err) {
                            reject(err)
                            // remove uploaded file
                            fs.unlink(srcpath, () => {})
                            return
                        }

                        resolve()
                    })
                }

                resolve()
            })
        }).then(() => {
            return new Promise((resolve, reject) => {
                // 上传图片
                cos.putObject(params, (err, data) => {
                    if (err) {
                        reject(err)
                        // remove uploaded file
                        fs.unlink(srcpath, () => {})
                        return
                    }

                    resolve({
                        imgUrl: `https://${config.cos.fileBucket}-${config.qcloudAppId}.cos.${config.cos.region}.myqcloud.com/${uploadFolder}${imgKey}`,
                        imgUrlv4: `http://${config.cos.fileBucket}-${config.qcloudAppId}.cos${regionMap[config.cos.region]}.myqcloud.com/${uploadFolder}${imgKey}`,
                        size: imageFile.size,
                        mimeType: resultType.mime,
                        name: imgKey,
                        fileBucket: config.cos.fileBucket,
                        qcloudAppId: config.qcloudAppId,
                        region: config.cos.region,
                        uploadFolder,
                        imgKey
                    })

                    // remove uploaded file
                    fs.unlink(srcpath, () => {})
                })
            })
        })
    }).catch(e => {
        if (e.statusCode === 413) {
            debug('%s: %o', ERRORS.ERR_FILE_EXCEEDS_MAX_SIZE, e)
            throw new Error(`${ERRORS.ERR_FILE_EXCEEDS_MAX_SIZE}\n${e}`)
        } else {
            throw e
        }
    })
}