重拾koa2之文件上传

const Koa = require('koa2')
const path = require('path')
const app = new Koa()
//const bodyParser = require('koa-bodyparser)

const{ uploadFile } = require('./busboy.js')

//app.use(bodyParser())

app.use(async (ctx)=>{

    if(ctx.url === '/' && ctx.method === 'GET'){
        //当GET请求时候返回表单页面
        let html = `
        <h1>koa2 upload demo</h1>
        <form method="POST" action="/upload.json" enctype="multipart/form-data">
          <p>file upload</p>
          <span>picName:</span><input name="picName" type="text" /><br/>
          <input name="file" type="file" /><br/><br/>
          <button type="submit">submit</button>
        </form>
        `
        ctx.body = html
    }else if(ctx.url === '/upload.json'&& ctx.method === 'POST'){
        //上传文件请求处理
        let result = {success:false}
        let serverFilePath = path.join(__dirname,'uplaod-files')

        //上传文件事件
        result = await uploadFile(ctx,{
            fileType:'album',
            path:serverFilePath
        })

        ctx.body = result
    }else{
        //其他请求显示404
        ctx.body = '404'
    }

})

app.listen(3000,()=>{
    console.log('busboy is running ')
})

const inspect = require('util').inspect
const path = require('path')
const os = require('os')
const fs = require('fs')
const Busboy = require('busboy')

// 同步创建文件目录
function mkdirsSync(dirname) {
    if (fs.existsSync(dirname)) {
        return true
    } else {
        if (mkdirsSync(path.dirname(dirname))) {
            fs.mkdirSync(dirname)
            return true
        }
    }
}

// 获取上传文件的后缀名
function getSuffixNmae(fileName) {
    let nameList = fileName.split('.')
    return nameList[nameList.length - 1]
}

// 上传文件
function uploadFile(ctx, option) {
    let req = ctx.req
    let res = ctx.res
    let busboy = new Busboy({ headers: req.headers })

    //获取类型
    let fileType = option.fileType || 'common'
    let filePath = path.join(option.path, fileType)
    let mkdirResult = mkdirsSync(filePath)

    return new Promise((resolve, reject) => {
        console.log('文件上传中...')
        let result = {
            success: false,
            formData: {},
        }

        //解析请求文件事件
        busboy.on('file', function (fieldname, file, filename, encoding, mimetype) {
            let fileName = Math.random().toString(16).substr(2) + '.' + getSuffixNmae(filename)
            let _uploadFilePath = path.join(filePath,fileName)
            let saveTo = path.join(_uploadFilePath)

            //文件保存到指定路径
            file.pipe(fs.createWriteStream(saveTo))

            file.on('data',function(data){
                console.log(`File [${fileName}] got ${data.length} bytes`)

            })
            //文件写入事件结束
            file.on('end', function () {
                result.success = true
                result.message = '文件上传成功！'
                resolve(result)
            })  
        })

        //解析表单中其他字段信息
        busboy.on('field',function(fieldname,val,fieldnameTruncated,valTruncated,encoding,mimetype){
            console.log('表单字段数据['+fieldname+']:value'+inspect(val))
            result.formData[fieldname] = inspect(val)
        })

        //解析结束事件
        busboy.on('finish',function(){
            console.log('文件结束')
            resolve(result)
        })

        //解析错误事件
        busboy.on('error',function(err){
            console.log('文件上出错')
            reject(result)
        })

        req.pipe(busboy)
    })
}

module.exports= {
    uploadFile
}