FB16362713: `NSWorkspace.shared.urlsForApplications(toOpen: .html)` is missing some apps

[sindresorhus]

• Date: 2025-01-20
• Resolution: Open
• Area: AppKit
• OS: macOS 15.2
• Type: Incorrect/Unexpected Behavior

Description

For example, the Zen Browser app (https://zen-browser.app) is able (registered to handle) to open HTML documents, but does not show up in the list. Same with Firefox. However, they do show up with LSCopyAllRoleHandlersForContentType(kUTTypeHTML, .viewer)?.takeRetainedValue() as? [String] ?? []. The former is documented as a replacement for the latter, but it seems they use different logic. I initially thought there was something wrong with my system, but I also got a report from a user on one of my apps that uses NSWorkspace.shared.urlsForApplications(toOpen: .html) that said Zen Browser was missing, so there is definitely something going on.

I have tried both in a sanboxed and unsandboxed app.

The missing apps live in /Applications, but same result if they are in ~/Applications. I have also tried turning Spotlight off and on again. And I have tried resetting lsregister. Restarting computer. Nothing helped.

The "default browser" setting in System Settings does include Zen Browser, so I have a feeling it is using the older API.

NSWorkspace.shared.urlsForApplications(toOpen: "https:") also does not return Zen Browser, even though the app registers to handle https and http schemes.

---

I have written a simple script to compare the output of these methods:

func compareHTMLHandlers() {
	// Get URLs from NSWorkspace
	let workspaceURLs = NSWorkspace.shared.urlsForApplications(toOpen: .html)
	let workspaceHandlers = Set(workspaceURLs.compactMap { url -> String? in
		Bundle(url: url)?.bundleIdentifier
	})

	// Get handlers from Launch Services
	let lsHandlers = Set(LSCopyAllRoleHandlersForContentType(kUTTypeHTML, .viewer)?.takeRetainedValue() as? [String] ?? [])

	// Find differences
	let onlyInWorkspace = workspaceHandlers.subtracting(lsHandlers)
	let onlyInLaunchServices = lsHandlers.subtracting(workspaceHandlers)

	// Print results
	print("Only in NSWorkspace:")
	for bundleID in onlyInWorkspace.sorted() {
		if let appURL = NSWorkspace.shared.urlForApplication(withBundleIdentifier: bundleID) {
			print("- \(bundleID) (\(appURL.lastPathComponent))")
		} else {
			print("- \(bundleID)")
		}
	}

	print("\nOnly in Launch Services:")
	for bundleID in onlyInLaunchServices.sorted() {
		if let appURL = NSWorkspace.shared.urlForApplication(withBundleIdentifier: bundleID) {
			print("- \(bundleID) (\(appURL.lastPathComponent))")
		} else {
			print("- \(bundleID)")
		}
	}
}

compareHTMLHandlers()