我如何知道从 URL 下载完成的时间？

Question

On my project I use something like the following function to redirect users in order to download a file在我的项目中，我使用以下 function 来重定向用户以下载文件

function promptDownload(file){
      location.href = "http://example.com/downloads/"+file;
}

As we all know, when I call this function, browser only prompts a download dialog and does not interrupt my application flow.众所周知，当我调用这个function时，浏览器只会提示一个下载对话框，并不会中断我的应用流程。 What I would like to do is to determine when this download completed or cancelled.我想做的是确定此下载何时完成或取消。

There should be something like onLoad , onFinishedLoading , onConnectionEnd or etc but I couldn't find anything.应该有类似onLoad 、 onFinishedLoading 、 onConnectionEnd等的东西，但我找不到任何东西。

Answer 1

You can't determine download progress if you download the file that way.如果您以这种方式下载文件，则无法确定下载进度。

If you download the file using XMLHttpRequest , then you can listen for load, error and progress events like this:如果您使用XMLHttpRequest下载文件，那么您可以像这样监听加载、错误和进度事件：

function log(message) {
  return function () {
    alert(message);
  };
}

function download(file, callback) {
  var request = new XMLHttpRequest();
  request.responseType = 'blob';
  request.open('GET', file);
  request.addEventListener('load', log('load ' + file));
  request.addEventListener('error', log('error ' + file));
  request.addEventListener('progress', log('progress ' + file));
  request.addEventListener('load', function () {
    callback(request.response);
  });
  request.send();
}

function save(object, mime, name) {
  var a = document.createElement('a');
  var url = URL.createObjectURL(object);
  a.href = url;
  a.download = name;
  a.click();
}

document.querySelector('#download').addEventListener('click', function () {
  download('test.pdf', function (file) {
    save(file, 'application/pdf', 'test.pdf');
  });
});

<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
  </head>
  <body>
    <button id="download">Download</button>
    <script src="script.js"></script>
  </body>
</html>

我如何知道从 URL 下载完成的时间？

问题描述

1 个解决方案

解决方案1
3 已采纳 2017-04-25 17:58:00

我如何知道从 URL 下载完成的时间？

问题描述

1 个解决方案

解决方案1 3 已采纳 2017-04-25 17:58:00

解决方案1
3 已采纳 2017-04-25 17:58:00