How do I configure custom URL handlers on OS X?

Question

I've been reading a lot online about custom URL handlers / custom protocol handlers such as:

• Launching External Applications using Custom Protocols under OSX
• OS X URL handler to open links to local files

I get that you can tell the system that a particular program is able to handle a certain scheme / protocol with the Info.plist file:

<key>CFBundleURLTypes</key>
<array>
    <dict>
        <key>CFBundleURLName</key>
        <string>Local File</string>
        <key>CFBundleURLSchemes</key>
        <array>
            <string>local</string>
        </array>
    </dict>
</array>
<key>NSUIElement</key>
<true/>

But if there are multiple applications that are capable of opening the same URL handler, such as mailto: how do you specify which one you want the system to use?

There were some references to utilities like the More Internet preference pane which no longer seems to be available from the author's site. I did find it online by Googling but it seems a bit shaky - like it was written for an older OSX - perhaps Tiger.

I haven't been able to find information on how to set the URL handler for protocols and custom protocols. I'm assuming there is a plist file somewhere that I can edit - or maybe there is a newer, better utility that works well with Mountain Lion?

Answer 1

The file you seek is ~/Library/Preferences/com.apple.LaunchServices/com.apple.launchservices.secure.plist.

It holds an array called LSHandlers, and the Dictionary children that define an LSHandlerURLScheme can be modified accordingly with the LSHandlerRole.

Rather than manually editing this file, you can also use RCDefaultApp, which gives you a nice Preference Pane. It is said not to be working for macOS 10.12 and up, but I can confirm it runs under macOS 10.14.

An alternative is SwiftDefaultApps.

For example, here's SVN and SSH:

… and in RCDefaultApp:

Answer 2

Update Jul 2017: RCDefaultApp and lstool no longer work on macOS 10.12 or later. We'll have to find a new solution.

Edit Mar 2018
I found SwiftDefaultApps but can't test as I'm not on High Sierra yet.

---

Furthering the previous answer, if you would like to do this on the command line you can use the lstool command, which is the core of RCDefaultApp, found under RCDefaultApp.prefPane/Contents/Resources/lstool.

Its usage is straightforward:

[~]$lstool --help
Usage:

lstool read [<lsscheme> [<type>]]
lstool [-n] write <lsscheme> <type> <app>
lstool [-n] setoption <lsscheme> <type> login|ignorecreator YES|NO
lstool [-n] register {<app>}
lstool [-n] unregister {<path> | <app>}
lstool apps

-n means do not make changes
<lsscheme> is one of: internet, media, url, extension, uti, mime, ostype
<app> is the path to an application or a name to be looked up

Answer 3

Listing current LaunchServices URL handler settings on Apple OS X 10.10 (Yosemite):

defaults read com.apple.LaunchServices/com.apple.launchservices.secure

Answer 4

I actually wrote an application simplifying registration of custom URL protocols, if anyone is interested. It is called LinCastor (http://onflapp.wordpress.com/lincastor/). Handlers can be defined as AppleScript or shell script (which can perl, python or what ever).

Answer 5

Open the file with XCode works quite easy.

Using the build in command plutil as described in the answer on https://discussions.apple.com/thread/5815759 to convert between format xml1 or binary1 works similar.

plutil -convert xml1 /file-i-wish

nano /file-i-wish & save file 

plutil -convert binary1 /file-i-wish

No need for 'alien' tools :-)

Answer 6

You can also use duti:

echo $'com.apple.mail mailto\ncom.googlecode.iterm2 x-man-page'>~/.duti;duti ~/.duti

Answer 7

I just tried the old More Internet, under El Capitan.

It is funky and the only way it works is via using the up and down arrow keys to select the protocol, and a drag/drop of the APP icon into the window to make a change.

I switched the default from Safari to Chrome, and the change stuck, so it works still.

Answer 8

Another way to list current LaunchServices URL handler settings with Xcode on Apple OS X 10.10+ (Yosemite):

open -a Xcode ~/Library/Preferences/com.apple.LaunchServices/com.apple.launchservices.secure.plist