Question

I am trying to find a way where by we can auto save a file in Firefox using JS. The way I have done till yet using FireShot on a Windows Desktop:

var element = content.document.createElement("FireShotDataElement");
element.setAttribute("Entire", EntirePage);
element.setAttribute("Action", Action);
element.setAttribute("Key", Key);
element.setAttribute("BASE64Content", "");
element.setAttribute("Data", Data);
element.setAttribute("Document", content.document);
if (typeof(CapturedFrameId) != "undefined")
  element.setAttribute("CapturedFrameId", CapturedFrameId);
content.document.documentElement.appendChild(element);
var evt = content.document.createEvent("Events");
evt.initEvent("capturePageEvt", true, false);
element.dispatchEvent(evt);

But the issue is that it opens a dialog box to confirm the local drive location details. Is there a way I can hard code the local drive storage location and auto save the file?

Answer 1

If you are creating a Firefox add-on then FileUtils and NetUtil.asyncCopy are your friends:

Components.utils.import("resource://gre/modules/FileUtils.jsm");
Components.utils.import("resource://gre/modules/NetUtil.jsm");

var TEST_DATA = "this is a test string";
var source = Components.classes["@mozilla.org/io/string-input-stream;1"].
                 createInstance(Components.interfaces.nsIStringInputStream);
source.setData(TEST_DATA, TEST_DATA.length);

var file = new FileUtils.File("c:\\foo\\bar.txt");
var sink = file.openSafeFileOutputStream(file, FileUtils.MODE_WRONLY |
                                               FileUtils.MODE_CREATE);
NetUtil.asyncCopy(source, sink);

This will asynchronously write the string this is a test string into the file c:\foo\bar.txt. Note that NetUtil.asyncCopy closes both streams automatically, you don’t need to do it. However, you might want to pass a function as third parameter to this method – it will be called when the write operation is finished.

See also: Code snippets, writing to a file