Parse an executable for strings and add DistributedNotification listeners for each

notifier.swift

//
//  notifier
//
//  Created by Josh Wisenbaker on 3/12/18.
//  Copyright © 2018 Josh Wisenbaker. All rights reserved.
//
//  @see https://gitlab.com/-/snippets/1704123
//
//  @see https://medium.com/macoclock/finding-distributed-notifications-on-macos-catalina-b2a292aac5a1
//
//  Modified by BrianHenryIE to parse executables for strings and add listeners for them.

import Foundation

// https://stackoverflow.com/questions/29514738/get-terminal-output-after-a-command-swift
extension String : LocalizedError {
    public var errorDescription: String? { self }
}
// https://stackoverflow.com/questions/29514738/get-terminal-output-after-a-command-swift
extension Process {
    func run(_ executableURL: URL, arguments: [String]? = nil) throws -> String {
        self.executableURL = executableURL
        self.arguments = arguments
        
        let pipe = Pipe()
        standardOutput = pipe
        standardError = pipe
        
        try run()
        _ = Timer.scheduledTimer(withTimeInterval: 2.0, repeats: true) { timer in
            self.terminate()
        }
        // This never happens.
        waitUntilExit()
        
        let output = String(data: pipe.fileHandleForReading.readDataToEndOfFile(), encoding: .utf8)
        return output?.trimmingCharacters(in: .newlines) ?? ""
    }
}
// https://stackoverflow.com/questions/27624331/unique-values-of-array-in-swift
extension Array where Element: Equatable {
    var unique: [Element] {
        var uniqueValues: [Element] = []
        forEach { item in
            guard !uniqueValues.contains(item) else { return }
            uniqueValues.append(item)
        }
        return uniqueValues
    }
}
// https://stackoverflow.com/questions/24181699/how-to-check-if-a-file-exists-in-the-documents-directory-in-swift
extension FileManager {
    class func fileExists(filePath: String) -> Bool {
        var isDirectory = ObjCBool(false)
        return self.default.fileExists(atPath: filePath, isDirectory: &isDirectory)
    }
}

// https://gitlab.com/-/snippets/1704123
class watcher {
    init() {

    let filePath = CommandLine.arguments[1]

    if !FileManager.fileExists(filePath: filePath) {
        print("File not found: \(filePath)")
        exit(1)
    }

    let taskProcess = Process()

    print("Getting strings for \(filePath)")

    let result: String = try! taskProcess.run(
        URL(filePath: "/usr/bin/strings"),
        arguments: [
           filePath
        ]
    )

    let potentialNotificationNames = result.split(separator: "\n").map { String($0) }.unique

       potentialNotificationNames.forEach(
            { 
                print("adding listener for \($0)")
                
                DistributedNotificationCenter.default().addObserver(self,
                                                                   selector: #selector(self.logit(note:)),
                                                                   name: Notification.Name($0),
                                                                   object: nil) }
        )
    }
    
    @objc func logit(note: NSNotification) {
        print(note)
    }
}

let myWatcher = watcher()

dispatchMain()

Use:

$ swiftc notifier.swift
$ ./notifier /System/Library/CoreServices/backupd.bundle/Contents/Resources/backupd-helper
Getting strings for /System/Library/CoreServices/backupd.bundle/Contents/Resources/backupd-helper
adding listener for @fpmc
...
adding listener for B48@0:8@16@24Q32^@40
__CFNotification 0x600002748000 {name = com.apple.TimeMachine.UICleanupNeeded; object = com.apple.backupd; userInfo = {
    DestinationID = "511D3A0B-8810-4704-B45B-E2A2FFC26DAE";
}}