Titanium Community Questions & Answer Archive

Question

Getting a file size from a server before downloading it

Is there a way to get the file size of say a zip file before it gets downloaded. As detailed in this post https://developer.appcelerator.com/question/26001/copying-a-file-from-a-server-to-your-harddisk, I can download the file. I would like to give my application like a status bar or something but in order to do this I need the file size. I tried using header information but I can't seem to access it until after it is done downloading.

Answer 1

This is not always supported by the webserver, but the HTTP method "HEAD" can be used for this purpose. An example on how to use it (untested, but should work):

  var xhr = Titanium.Network.createHTTPClient();
  xhr.onload = function() {
    Ti.API.info( this.getResponseHeader('Content-Length') );
  };

  xhr.open('HEAD', url);
  xhr.send();

So send a HEAD request of the download URL, if you get the Content-Length in the response headers you know the size, else you can display a more generic/animated progress indicator.

(You can try Ti.API.info( this.getResponseHeaders() ); instead for more header variables.)

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Getting a file size from a server before downloading it

1 Answer