在傳統(tǒng)的HTTP應(yīng)用上傳文件想要同時(shí)上傳多個(gè)文件并查看上傳進(jìn)度是一件很麻煩的事情,當(dāng)然現(xiàn)在也有一些基于SWF的文件上傳組件提供這種的便利性.到了HTML5下對(duì)文件的讀取和上傳的控制方面就非常靈活,HTML5提供一系列的AIP進(jìn)行文件讀取,包括計(jì)取文件某一塊的內(nèi)容也非常方便,結(jié)合Websocket進(jìn)行文件的傳輸就變得更加方便和靈活.下面通過(guò)使用HTML5結(jié)合websocet簡(jiǎn)單地實(shí)現(xiàn)多文件同時(shí)上傳應(yīng)用.
實(shí)現(xiàn)功能
大概預(yù)覽一下需要做的功能:
主要功能是用戶可以直接把文件夾的文件直接拖放到網(wǎng)頁(yè)中,并進(jìn)行上傳,在上傳的過(guò)程中顯示上傳進(jìn)度信息.
FileInfo類(lèi)封裝
為了方便讀取文件信息,在原有File的基礎(chǔ)封裝了一個(gè)簡(jiǎn)單文件信息讀取的對(duì)象類(lèi).
function FileInfo(file, pagesize) {
this.Size = file.size;
this.File = file;
this.FileType = file.type;
this.FileName = file.name;
this.PageSize = pagesize;
this.PageIndex = 0;
this.Pages = 0;
this.UploadError = null;
this.UploadProcess = null;
this.DataBuffer = null;
this.UploadBytes = 0;
this.ID = Math.floor(Math.random() * 0x10000).toString(16);
this.LoadCallBack = null;
if (Math.floor(this.Size % this.PageSize) > 0) {
this.Pages = Math.floor((this.Size / this.PageSize)) + 1;
}
else {
this.Pages = Math.floor(this.Size / this.PageSize);
}
}
FileInfo.prototype.Reset = function () {
this.PageIndex = 0;
this.UploadBytes = 0;
}
FileInfo.prototype.toBase64String = function () {
var binary = ''
var bytes = new Uint8Array(this.DataBuffer)
var len = bytes.byteLength;
for (var i = 0; i < len; i++) {
binary += String.fromCharCode(bytes[i])
}
return window.btoa(binary);
}
FileInfo.prototype.OnLoadData = function (evt) {
var obj = evt.target["tag"];
if (evt.target.readyState == FileReader.DONE) {
obj.DataBuffer = evt.target.result;
if (obj.LoadCallBack != null)
obj.LoadCallBack(obj);
}
else {
if (obj.UploadError != null)
obj.UploadError(fi, evt.target.error);
}
}
FileInfo.prototype.Load = function (completed) {
this.LoadCallBack = completed;
if (this.filereader == null || this.filereader == undefined)
this.filereader = new FileReader();
var reader = this.filereader;
reader["tag"] = this;
reader.onloadend = this.OnLoadData;
var count = this.Size - this.PageIndex * this.PageSize;
if (count > this.PageSize)
count = this.PageSize;
this.UploadBytes += count;
var blob = this.File.slice(this.PageIndex * this.PageSize, this.PageIndex * this.PageSize + count);
reader.readAsArrayBuffer(blob);
};
FileInfo.prototype.OnUploadData = function (file) {
var channel = file._channel;
var url = file._url;
channel.Send({ url: url, parameters: { FileID: file.ID, PageIndex: file.PageIndex, Pages: file.Pages, Base64Data: file.toBase64String()} }, function (result) {
if (result.status == null || result.status == undefined) {
file.PageIndex++;
if (file.UploadProcess != null)
file.UploadProcess(file);
if (file.PageIndex < file.Pages) {
file.Load(file.OnUploadData);
}
}
else {
if (file.UploadError != null)
file.UploadError(file, data.status);
}
});
}
FileInfo.prototype.Upload = function (channel, url) {
var fi = this;
channel.Send({ url: url, parameters: { FileName: fi.FileName, Size: fi.Size, FileID: fi.ID} }, function (result) {
if (result.status == null || result.status == undefined) {
fi._channel = channel;
fi._url = result.data;
fi.Load(fi.OnUploadData);
}
else {
if (file.UploadError != null)
file.UploadError(fi, result.status);
}
});
}
類(lèi)的處理很簡(jiǎn)單,通過(guò)file初始化并指定分塊大小來(lái)實(shí)始化一些文件信息,如頁(yè)數(shù)量頁(yè)大小等.當(dāng)然最重要還封裝文件對(duì)應(yīng)的Upload方法,用于把文件塊信息打包成base64信息通過(guò)Websocket的方式發(fā)送到服務(wù)器.
文件拖放
在HTML5中接受系統(tǒng)文件拖放進(jìn)來(lái)并不需要做復(fù)雜的事情,只需要針對(duì)容器元素綁定相關(guān)事件即可.
function onDragEnter(e) {
e.stopPropagation();
e.preventDefault();
}
function onDragOver(e) {
e.stopPropagation();
e.preventDefault();
$(dropbox).addClass('rounded');
}
function onDragLeave(e) {
e.stopPropagation();
e.preventDefault();
$(dropbox).removeClass('rounded');
}
function onDrop(e) {
e.stopPropagation();
e.preventDefault();
$(dropbox).removeClass('rounded');
var readFileSize = 0;
var files = e.dataTransfer.files;
if (files.length > 0) {
onFileOpen(files);
}
}
只需要在onDrop過(guò)程中獲取相關(guān)拖放文件即可,這些可能通過(guò)一些HTML5的教程可以得到幫助。
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