浏览器关闭/上传取消时如何停止文件传输
本文关键字:何停止 文件 传输 取消 浏览器 | 更新日期: 2023-09-27 18:16:58
我上传一个文件异步与HTML5在MVC3。如果我有一个大文件,比如1GB大小,在上传完成50%后我取消上传或关闭浏览器,它仍然会在目标文件夹中保存一个500MB的文件。
我如何在控制器和客户端处理这个问题?
这是我的控制器动作:
[HttpPost]
public ActionResult Upload(object fileToUpload1)
{
var fileName = Request.Headers["X-File-Name"];
var fileSize = Request.Headers["X-File-Size"];
var fileType = Request.Headers["X-File-Type"];
Request.SaveAs("D:''uploadimage''" + fileName, false);
if (fileToUpload1 == null)
{
return Json(true, JsonRequestBehavior.AllowGet);
}
else { return Json(false, JsonRequestBehavior.AllowGet); }
// return Json(false, JsonRequestBehavior.AllowGet);
}
这里是Javascript:
// Uploading - for Firefox, Google Chrome and Safari
xhr = new XMLHttpRequest();
// Update progress bar
xhr.upload.addEventListener("progress", uploadProgress, false);
function uploadProgress(evt) {
if (evt.lengthComputable) {
var percentComplete = Math.round(evt.loaded * 100 / evt.total);
//assign value to prgress bar Div
var progressBar = document.getElementById("progressBar");
progressBar.max = evt.total;
progressBar.value = evt.loaded;
}
}
// File load event
xhr.upload.addEventListener("load", loadSuccess, false);
function loadSuccess(evt) {
$(fileParentDivobj).find(".ImgDiv").find("span").html("uploaded");
addfile(fileParentDivobj);
}
//handling error
xhr.addEventListener("error", uploadFailed, false);
xhr.addEventListener("abort", uploadCanceled, false);
function uploadFailed(evt) {
alert("There was an error attempting to upload the file.");
}
function uploadCanceled(evt) {
alert("The upload has been canceled by the user or the browser dropped the connection.");
}
xhr.open("POST", "@Url.Action("Upload","Home")", true);
// Set appropriate headers
xhr.setRequestHeader("Cache-Control", "no-cache");
xhr.setRequestHeader("X-Requested-With", "XMLHttpRequest");
xhr.setRequestHeader("Content-Type", "multipart/form-data");
xhr.setRequestHeader("X-File-Name", file.fileName);
xhr.setRequestHeader("X-File-Size", file.fileSize);
xhr.setRequestHeader("X-File-Type", file.type);
xhr.setRequestHeader("X-File", file);
// Send the file (doh)
xhr.send(file);
首先,这不是应该使用任何客户端脚本解决的问题,因为我不相信当浏览器关闭时您将能够发出新的请求,并且当连接因网络问题而中断时,它肯定不会工作。
所以我做了一些挖掘,我没有在asp.net中发现任何会告诉我请求连接被中断的东西。然而,我们可以检查我们收到了多少数据,我们应该收到多少数据!
public ActionResult Upload()
{
// I like to keep all application data in App_Data, feel free to change this
var dir = Server.MapPath("~/App_Data");
if (!Directory.Exists(dir))
Directory.CreateDirectory(dir);
// extract file name from request and make sure it doesn't contain anything harmful
var name = Path.GetFileName(Request.Headers["X-File-Name"]);
foreach (var c in Path.GetInvalidFileNameChars())
name.Replace(c, '-');
// construct file path
var path = Path.Combine(dir, name);
// this variable will hold how much data we have received
var written = 0;
try
{
using (var output = new FileStream(path, FileMode.Create, FileAccess.Write, FileShare.None))
{
var buffer = new byte[0x1000];
var read = 0;
// while there is something to read, write it to output and increase counter
while ((read = Request.InputStream.Read(buffer, 0, buffer.Length)) > 0)
{
output.Write(buffer, 0, read);
output.Flush();
written += read;
}
}
}
finally
{
// once finished (or when exception was thrown) check whether we have all data from the request
// and if not - delete the file
if (Request.ContentLength != written)
System.IO.File.Delete(path);
}
return Json(new { success = true });
}
测试你的客户端代码使用使用asp.net开发服务器和谷歌浏览器。
编辑:刚刚注意到Chuck Savage在之前的评论中发布了这个原则,所以要感谢他:)
专注于请求是忘记响应的原因,响应可以告诉客户端是否仍然连接(Response. isclientconnected)。
通过简单地检查是否有东西要读,您可以忽略客户端可能出现的长(多长?)网络延迟的情况。
使用Chunk和Lukas方法并合并响应。IsClientConnected属性和您选择的线程Sleep,以防没有东西可读,但客户端仍处于连接状态。这样,如果需要的话,您可以更早地退出读循环,而无需从客户机用户生成WTF。