在傳統(tǒng)的HTTP應(yīng)用上傳文件想要同時上傳多個文件并查看上傳進度是一件很麻煩的事情,當然現(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進行文件讀取,包括計取文件某一塊的內(nèi)容也非常方便,結(jié)合Websocket進行文件的傳輸就變得更加方便和靈活.下面通過使用HTML5結(jié)合websocet簡單地實現(xiàn)多文件同時上傳應(yīng)用.
實現(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)頁中,并進行上傳,在上傳的過程中顯示上傳進度信息.
FileInfo類封裝
為了方便讀取文件信息,在原有File的基礎(chǔ)封裝了一個簡單文件信息讀取的對象類.
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);
}
});
}
類的處理很簡單,通過file初始化并指定分塊大小來實始化一些文件信息,如頁數(shù)量頁大小等.當然最重要還封裝文件對應(yīng)的Upload方法,用于把文件塊信息打包成base64信息通過Websocket的方式發(fā)送到服務(wù)器.
文件拖放
在HTML5中接受系統(tǒng)文件拖放進來并不需要做復(fù)雜的事情,只需要針對容器元素綁定相關(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過程中獲取相關(guān)拖放文件即可,這些可能通過一些HTML5的教程可以得到幫助。
這時候只需要針對選擇的文件構(gòu)建相關(guān)FileInfo對象,并調(diào)用上傳方法即可.
function onFileOpen(files) {
if (files.length > 0) {
for (var i = 0; i < files.length; i++) {
var info = new FileInfo(files[i], 32768);
uploads.push(info);
info.UploadProcess = onUploadProcess;
addUploadItem(info);
}
}
}
通過UploadProcess事件對上傳文件進度信息進行一個設(shè)置更新
function onUploadProcess(file) {
$('#p_' + file.ID).progressbar({ value: (file.PageIndex / file.Pages) * 100,
text: file.FileName + '[' + file.UploadBytes + '/' + file.Size + ']'
});
}
C#服務(wù)端
借助于Beetle對websocket的支持對應(yīng)服務(wù)端的實現(xiàn)就非常簡單了
/// <summary>
/// Copyright © henryfan 2012
///CreateTime: 2012/12/14 21:13:34
/// </summary>
public class Handler
{
public void UploadPackage(string FileID, int PageIndex, int Pages, string Base64Data)
{
Console.WriteLine("FileID:{2},PageIndex:{0} Pages:{1} DataLength:{3}", PageIndex, Pages, FileID,Base64Data.Length);
}
public string UploadFile(string FileID, string FileName, long Size)
{
Console.WriteLine("FileID:{2},FileName:{0} Size:{1}", FileName, Size, FileID);
return "Handler.UploadPackage";
}
}
服務(wù)端方法有兩個一個是上傳文件請求,和一個上傳文件塊接收方法.
總結(jié)
只需要以上簡單的代碼就能實現(xiàn)多文件同時上傳功能,在這采用json來處理上傳的信息,所以文件流要進行一個base64的編碼處理,由于websocket瀏覽提交的數(shù)據(jù)一般都有MASK處理再加上base64那損耗相對來說比較重,實際上websocket有提供流的數(shù)據(jù)包格式(arraybuffer);當然這種處理在操作上就沒有json來得方便簡單.
下載代碼:WebSocketUpload.rar
以上就是本文的全部內(nèi)容，希望對大家的學習有所幫助，也希望大家多多支持腳本之家。
