How to force Chrome to NOT open SaveAs Dialog when downloading a URL?

Question

Chrome Build: the newest, 33+

A Chrome Extension extracts certain urls from currently viewed site and then downloads a subset of them (quite often hundreds of files).

Expected Behavior:

Files are downloaded into the default Download-Folder without questioning where and under which filename they have to be saved.

Problem:

If a user has enabled the option "Ask where to save each file before downloading" in Chrome->Settings->Advanced Settings->Downloads then when trying to download, for example, 100 files simultaniously, Chrome tries to open 100 SaveAs Dialogs and crashes.

What I tried:

• to use chrome.downloads.download(object options, function callback) method with an option saveAs: false

• using the following code to trigger a download through an emulated mousevent:

  function saveAs(Url,filename){
    var blob=new Blob([''], {type:'application/octet-stream'}); 
    var url = webkitURL.createObjectURL(blob);
    var a = document.createElementNS('http://www.w3.org/1999/xhtml','a');
    a.href = Url;
    a.download = filename; 
    var e = document.createEvent('MouseEvents');
    e.initMouseEvent('click', false, false, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null);
    a.dispatchEvent(e);
    webkitURL.revokeObjectURL(url);
  }
  

Answer 1

It is impossible when "Ask where to save each file before downloading" Enabled (as of 70.0.3538.77). The corresponding Chromium bug is:

Bug 417112: chrome.downloads.download ignore saveAs

Moreover setting filename in chrome.downloads.downloads() also doesn't work.

Bug 758094: Extension can not rename downloaded file