Creating a recording in Swift - swift

Question

I'm beginning to teach myself Swift by creating an app that lets users record voice memos. Many of the previous questions on this topic seem to use an outdated version of Swift, so I thought I'd ask the community for their help.
The problem seems to lie either in my playAudio() function or in my viewDidLoad() function where I set up the recording URL (or both). Please let me know if I can provide additional information.
#IBAction func playAudio(sender: AnyObject) throws {
if audioRecorder?.recording == false {
stopButton.enabled = true
recordButton.enabled = false
let path = NSBundle.mainBundle().pathForResource("audioFile", ofType: "m4a")
let fileURL = try NSURL(fileURLWithPath: path!)
audioPlayer = try AVAudioPlayer(contentsOfURL: fileURL, fileTypeHint: nil)
audioPlayer.prepareToPlay()
audioPlayer.delegate = self
print("here you go!")
}
}
override func viewDidLoad() {
super.viewDidLoad()
playButton.enabled = false
stopButton.enabled = false
do {
let dirPaths =
NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
let baseURL = NSURL(string: dirPaths[0])
let soundFileURL = NSURL(string:"sound.caf", relativeToURL: baseURL)
let absoluteURL = soundFileURL!.absoluteURL
let recordSettings = [AVEncoderAudioQualityKey: AVAudioQuality.Min.rawValue, AVEncoderBitRateKey: 16, AVNumberOfChannelsKey: 2, AVSampleRateKey: 44100.0]
var error: NSError?
let audioSession = AVAudioSession.sharedInstance()
try audioSession.setCategory(AVAudioSessionCategoryPlayAndRecord, withOptions: [])
if let err = error {
print("audioSession error: \(err.localizedDescription)")
}
try audioRecorder = AVAudioRecorder(URL: absoluteURL, settings: recordSettings as! [NSObject : AnyObject] as! [String: AnyObject])
print(audioRecorder!.url)
if let err = error {
print("audioSession error: \(err.localizedDescription)")
} else {
audioRecorder?.prepareToRecord()
}
} catch {
print("catching error!")
}