How do you convert a local (filesystem) URI to path?
It can be done with nsIIOService + newURI() + QueryInterface(Components.interfaces.nsIFileURL) + file.path but that seems like a long way.
Is there a shorter way?

Here is an example code:

var aFileURL = 'file:///C:/path-to-local-file/root.png';
var ios = Components.classes["@mozilla/network/io-service;1"]
              .getService(Components.interfaces.nsIIOService);
var url = ios.newURI(aFileURL, null, null); // url is a nsIURI

// file is a nsIFile    
var file = url.QueryInterface(Components.interfaces.nsIFileURL).file;

console.log(file.path); // "C:\path-to-local-file\root.png"

How do you convert a local (filesystem) URI to path?
It can be done with nsIIOService + newURI() + QueryInterface(Components.interfaces.nsIFileURL) + file.path but that seems like a long way.
Is there a shorter way?

Here is an example code:

var aFileURL = 'file:///C:/path-to-local-file/root.png';
var ios = Components.classes["@mozilla/network/io-service;1"]
              .getService(Components.interfaces.nsIIOService);
var url = ios.newURI(aFileURL, null, null); // url is a nsIURI

// file is a nsIFile    
var file = url.QueryInterface(Components.interfaces.nsIFileURL).file;

console.log(file.path); // "C:\path-to-local-file\root.png"

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• Can you show example of what you're starting with and what you want to end up with. Optional: Also a snippet to show how you currently do it. – Noitidart Commented Jul 18, 2014 at 5:00
• Ah cool question, you're trying to turn it into a path you can feed the DOMFile API right? – Noitidart Commented Jul 18, 2014 at 6:07
• @Noitidart I want to use it for file upload as per my other 2 questions – erosman Commented Jul 18, 2014 at 7:34

1 Answer 1

The supported way is actually what you're already doing. Write yourself a helper function if you find it too verbose. Of course, you can shorten it a bit using the various helpers.

const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
Cu.import("resource://gre/Services.jsm");

var aFileURL = 'file:///C:/path-to-local-file/root.png';
var path = Services.io.newURI(aFileURL, null, null).
           QueryInterface(Ci.nsIFileURL).file.path;

Or:

const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
Cu.import("resource://gre/modules/NetUtil.jsm");

var aFileURL = 'file:///C:/path-to-local-file/root.png';
var path = NetUtil.newURI(aFileURL).QueryInterface(Ci.nsIFileURL).file.path;