我正在尝试上传文件的一部分(使用HTML5文件API、切片和XmlHttpRequest2),并向用户报告进度。我遇到的问题是,进度事件通常几乎立即触发(即使使用5MB的块大小),'loaded'值等于块的大小。当然,在上传期间可能需要30秒,而用户没有任何反馈。如果有人可以帮忙,请看下面的代码?我几乎要抓狂了,但找不到任何遇到相同问题的人!...
var startPosition = (partNumber - 1) * PART_SIZE;
var blob;
if (typeof fileUpload.File.slice != "undefined")
{
blob = fileUpload.File.slice(startPosition, startPosition + contentLength);
}
else
{
if (typeof fileUpload.File.webkitSlice != "undefined")
blob = fileUpload.File.webkitSlice(startPosition, startPosition + contentLength);
if (typeof fileUpload.File.mozSlice != "undefined")
blob = fileUpload.File.mozSlice(startPosition, startPosition + contentLength);
}
fileUpload.PartNumber = partNumber;
var xhr = new XMLHttpRequest();
// Add event listener for progress
xhr.upload.onprogress = function (event)
{
log.debug("progress " + event.loaded);
if (event.lengthComputable)
UpdateProgress(fileUpload, event.loaded);
};
xhr.open("PUT", url, true);
xhr.setRequestHeader('authorization', result);
// Make the request an HTTP PUT
log.debug('Sending PUT request to ' + url);
xhr.send(blob);