A decoupled way to propagate URL opening in an iOS app over the Responder chain

URL+UIResponder.swift

/// Conforming to this protocol allows for URL handling
protocol URLHandler {
    /// Handle a URL
    ///
    /// - Parameter url: The propagated url
    /// - Returns: The handled status
    func handleURL(_ url: URL, options: [UIApplication.OpenExternalURLOptionsKey : Any], completionHandler completion: ((Bool) -> Void)?)
}

// MARK: - Error Propagation
extension UIResponder {
    /// Propagates a URL through the responder chain.
    ///
    /// - Parameters:
    ///   - url: The URL to propagate
    ///   - options: A dictionary of options to use when opening the URL. For a list of possible keys to include in this dictionary, see URL Options.
    ///   - completion: The block to execute with the results. Provide a value for this parameter if you want to be informed of the success or failure of opening the URL.
    func propagateURL(_ url: URL,
                      options: [UIApplication.OpenExternalURLOptionsKey : Any] = [:],
                      completionHandler completion: ((Bool) -> Void)? = nil) {
        // Check if we have a next, otherwise return `false` to indicate that the operation failed
        guard next != nil else {
            completion?(false)
            return
        }
        // Check if the next responder can handle URLs
        guard let urlHandler = next as? URLHandler else {
            // If not then carry on the propagation of the URL
            next?.propagateURL(url, options: options, completionHandler: completion)
            return
        }
        
        // Ask the Next to handle the URL
        urlHandler.handleURL(url, options: options) { [weak self] (status) in
            if status == false {
                // If the next failed to handle the URL, continue the propagation of the URL
                self?.next?.propagateURL(url, options: options, completionHandler: completion)
            }
        }
    }
}