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I am developing a Cocoa Mac app which dynamically generates and registers itself for URL schemes. However, when the application registers itself to handle a newly generated URL scheme (e.g. myscheme1423://), I would like to prevent the application from responding to any previously registered URL schemes.

I am using LSSetDefaultHandlerForURLScheme() for the purpose of registering a URL scheme; in conjunction, the application automatically overwrites it's Info.plist to contain the new scheme. As you may know, the LSSetDefaultHandlerForURLScheme() function adds the given bundleID/scheme to a Launch Services database. However, I couldn't find an equivalent Launch Services function to remove the same bundleID/scheme pair from the database.

I know that I could simply ignore any external events which originated from a URL scheme other than the one for which the app is actively registered, but it feels to me that there should be a simple way to completely wipe out the system's knowledge of the previous scheme. If my application goes through the process of registering for a new scheme more than a few hundred times, a point will come where a significant amount of space (for a Plist, at least) is being taken up on disk by a plethora of pointless pieces of data (i.e. the old Launch Services entries).

Alex Nichol
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  • Try the answers for http://apple.stackexchange.com/questions/64124/how-can-i-modify-the-list-of-applications-under-open-with There is CleanOpenWith (Apple Script) that can be added to your installer or application to do this: https://github.com/spaquet/CleanOpenWith/releases – Jason Harrison Oct 30 '15 at 18:05

1 Answers1

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I just fired up a playground and began playing. This is utterly undocumented but it appears to work.

Try passing ("None" as CFString) for the second parameter of 

LSSetDefaultHandlerForURLScheme()
Baum mit Augen
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Gregorio Litenstein
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  • I just noticed this does not actually work. It seems in recent versions, macOS automatically removes URL Schemes if they have no valid handlers; and even though LSSetDefaultHandlerForURLScheme will always succeed if the app is valid, after a couple seconds, the handler will be removed if the app is not registered as a handler for that scheme. – Gregorio Litenstein Mar 24 '17 at 22:27