nwjs 实现的 分块上传

1、先上核心工具类
/**
 * Created by Administrator on 2017/6/12.
 */
let fs = require("fs");
/**
 * Created by ZHX on 2017/6/12.
 */
function UploadFile(debug,file,tokenUrl,postUrl,params,progressFun,endFun){
    this.tokenUrl = tokenUrl;
    this.postUrl = postUrl;
    this.params = params;
    this.file = file;
    this.progressFun = progressFun;
    this.endFun = endFun;
    this.debugFun = debug;
}

UploadFile.prototype = {
    tokenUrl:"",
    postUrl:"",
    file:"",
    progressFun:"",
    endFun:"",
    buf:null,
    // 块大小 10M.
    filePiece:10485760,
    xhrHandler:"",
    XHR:"",
    params:{},
    // 记录每次开始位置
    bytesStart:0,
    debugFun:null,
    upload:function(){
        var self = this;
        /** request the server to figure out what's the token for the file: */
        var xhr = new XMLHttpRequest;

        var vars = {
            name: this.file['name'],
            size: this.file['size'],
        };
        var tokenUrl = fAddVars(vars, this.tokenUrl) + "&" + fGetRandom();
        xhr.open("GET", tokenUrl, !0);
        xhr.onreadystatechange = function() {
            if (xhr.readyState != 4 || xhr.status < 200)
                return false;
            var token;
            token = eval("(" + xhr.responseText + ")").token;
            self.postUrl = fAddVars(
                fMergeJson({token,size:self.file.size,name:self.file.name},self.params),
                self.postUrl);
            self.uploadFile(0);
        }
        xhr.send();
    },
    uploadFile(pos){
        this.buf = new Buffer(this.filePiece);
        this.bytesStart = pos;
        let fileSize = this.file.size;
        let self = this;
        fs.read(this.file.fd,this.buf,0,this.buf.length,pos,function(err, bytesRead, buffer) {
            try{
                self.XHR = new XMLHttpRequest;
                var _xhr = self.XHR, upload = _xhr.upload;
                self.xhrHandler = fExtend(self.loadHandler, self);
                upload.addEventListener("progress", self.xhrHandler, !1);
                _xhr.addEventListener("load", self.xhrHandler, !1);
                _xhr.addEventListener("loadend", self.xhrHandler, !1);
                let range = "bytes "+ pos + "-"+ (pos + buffer.length) + "/" + fileSize;
                _xhr.open("POST", self.postUrl, !0);
                _xhr.setRequestHeader("Content-Range", range);
                var blob = new Blob([buffer.buffer]);
                self.debugFun(blob);
                _xhr.send(blob);
            }catch(e)
            {
                alert(e);
            }
        });
    },
    loadHandler(event){
        var xhr = this.XHR;
        switch(event.type){
            case "load":
                this.debugFun("load");
                var uploaded = 0;
                var respJson = null;
                var bError = !1;
                // try {
                //
                // } catch(e) {
                //     bError = this.retriedTimes > 2;
                //     if (!bError) {
                //         // this.retry();
                //         return;
                //     }
                // }
                if (xhr.readyState == 4 && (xhr.status == 200 || xhr.status == 308)) {
                    uploaded = (respJson = eval("(" + xhr.responseText + ")")) ? respJson.start : -1;
                } else if (xhr.status < 500 && xhr.status >= 400) {
                    bError = !0;
                } else if (xhr.status < 200) {return;}
                /** the response can't process the request, so throws out the error. */
                bError = bError || respJson.success == false;

                //check whether upload complete yet
                if(uploaded < this.file.size -1) {
                    this.retriedTimes = 0;
                    this.uploadFile(uploaded);
                } else {
                    this.endFun();
                }
                break;
            case "loaded":
                this.debugFun('.......................loading');
                break;
            case "progress":
                this.debugFun('progress-->'+this.bytesStart);
                this.progressFun(this.bytesStart + event.loaded);
                break;
        }
    }
};

function fExtend(a, b){
    var c = 2 < arguments.length ? [arguments[2]] : null;
    return function(){
        var d = "string" === typeof a ? b[a] : a,e=c ? [arguments[0]].concat(c) : arguments;
        return d.apply(b||d, e);
    };
}

function fAddVars(json, url, c) {
    var _array = [], _sep = "&", f = function(json, c) {
        var e = url ? /[]$/.test(url) ? url : url + "[" + c + "]" : c;
        "undefined" != e && "undefined" != c
        && _array.push("object" === typeof json
            ? fAddVars(json, e, !0)
            : "[object Function]" === Object.prototype.toString.call(json)
                ? encodeURIComponent(e) + "=" + encodeURIComponent(json())
                : encodeURIComponent(e) + "=" + encodeURIComponent(json))
    };
    if (!c && url)
        _sep = /?/.test(url) ? /?$/.test(url) ? "" : "&" : "?",
            _array.push(url),
            _array.push(fAddVars(json));
    else if ("[object Array]" === Object.prototype.toString.call(json)
        && "undefined" != typeof json)
        for (var g = 0, c = json.length; g < c; ++g)
            f(json[g], g);
    else if ("undefined" != typeof json && null !== json && "object" === typeof json)
        for (g in json)
            f(json[g], g);
    else
        _array.push(encodeURIComponent(url) + "=" + encodeURIComponent(json));
    return _array.join(_sep).replace(/^&/, "").replace(/%20/g, "+")
}

function fGetRandom() {
    return (new Date).getTime().toString().substring(8);
}

function fMergeJson(base, extend) {
    var result = {};
    for (var attr in base)
        result[attr] = base[attr];
    for (var attr in extend)
        result[attr] = extend[attr];
    return result;
}

module.exports = UploadFile;

2、file 文件格式：

   ① 通过fs.stat获取文件信息；
   ② 通过fs.open获取fd；
代码如下：

fs.stat(vf.path,function(err,stats){
    fs.open(vf.path,'r',function(err,fd){
        let lu = new LoadUtil(debug,{size:stats.size,name:util.getImageName(vf.path),fd:fd},backIp.ip+vf.tk,backIp.ip+vf.url,
            {id:vf.id},
        function(pro){
            send({type:"progress",data:{id:vf.id,progress:Math.round(pro/stats.size*100)}});
        },function(){
            send({type:"loaded",data:{id:vf.id}});
        });
        lu.upload();
    });
});