I am validating urls from NSSavePanel using the delegate's panel(_:validate) method, throwing error in case of invalid url. In such case the NSSavePanel presents an alert, which I want to customize (meaning present some human readable description) depending on the error thrown, keeping the save panel window open and then letting you choose another path.
LocalizedError works just fine when not using App Sandbox but in a sandboxed app the getter for error description is never called and the message in the alert is generic "Operation couldn't be completed. (#yourErrorType)", which I guess is somehow caused by the different inheritance chain for sandboxed NSSavePanels.
I am struggling figuring a way around this - is it possible to customize the alert somehow while still keeping the app sandboxed?
Addendum: Permissions for User Selected File => r/w. Running the following example produces different alerts with/without sandbox.
func runSavePanel()
{
let panel = NSSavePanel()
let delegate = SavePanelDelegate()
panel.delegate = delegate
_ = panel.runModal()
}
class SavePanelDelegate: NSObject, NSOpenSavePanelDelegate {
func panel(_ sender: Any, validate url: URL) throws {
throw CustomError.whatever
}
}
enum CustomError: LocalizedError {
case whatever
var errorDescription: String? {
get {
return "my description"
}
}
}
So, after a bit of further digging I can tell the solution of the riddle finally although I can only guess the reasons why it was made tricky by Apple. Apparently NSError exclusively needs to be used. The customization has to be done in userInfo, say
let userInfo = [NSLocalizedDescriptionKey: "yourLocalizedDescription", NSLocalizedRecoverySuggestionErrorKey: "yourSuggestion"]
throw NSError(domain: "whatever", code: 0, userInfo: userInfo)
etc. By the way subclassing NSError doesn't work, the Sandbox will just happily ignore you :)
Related
I've an intent parameter set as dynamic from the intent definition.
Let's say that the server where I get information for this option is currently down.
It is not clear how to present to users the fact that the options at the moment cannot be retrieved. The completion field where we should return the options also accepts an Error.
I've filled it with a subclass of Error and I've also implemented the LocalizedError protocol for this class... but when I encounter the error from the shortcut App, Apple is just presenting a pop up message that returns a terrible message not localized (but that includes the right Error name).
Here is the code that I'm using...
func provideCarModelOptions(for intent: CarIntent, with completion: #escaping ([String]?, Error?) -> Void) {
if(somethingGoesWrongWithServers()){
completion([],CarError.ServerDown)
}else{
completion(ReturnListOfModels(), nil)
}
}
And this is how I've implementend the CarError enum
public enum CarError:Error{
case serverDown
case generic
}
extension CarError : LocalizedError{
public var errorDescription: String? {
switch self {
case .serverDown:
return "Server is down"
case .generic:
return "SomethingGoesWrong"
}
}
}
Am I doing anything wrong or Apple is not handling the Errors the right way?
This worked for me to provide localized description:
completion(nil, INIntentError.init(_nsError: NSError(domain: "com.Domain.error", code: 0, userInfo: [NSLocalizedDescriptionKey: "Error Message"])))
i'm developping app using spotify-iOS-SDK, i have succesfully connect my app to Spotify and the audio is playing, but the problem is: When i close my PlaySongViewController, my app will be crash
"An instance of SPAudioStreamingController is already in use."
unless i stop my spotifyPlayer with this code after i logout
var spotifyPlayer: SPTAudioStreamingController?
#IBAction func closeView(_ sender: UIButton) {
print("close view")
self.dismiss(animated: true, completion: nil)
self.spotifyPlayer?.logout()
invalidateTimers()
}
func audioStreamingDidLogout(_ audioStreaming: SPTAudioStreamingController!) {
print("after logout")
try! self.spotifyPlayer?.stop()
}
The problem is continue if i close my ViewController directly before this code is working properly
self.spotifyPlayer = SPTAudioStreamingController.sharedInstance()
self.spotifyPlayer!.playbackDelegate = self
self.spotifyPlayer!.delegate = self
try! spotifyPlayer?.start(withClientId: auth.clientID)
self.spotifyPlayer!.login(withAccessToken: authSession.accessToken)
When i pick another song to open my PlaySongViewController again, it will be crashed with
"An instance of SPAudioStreamingController is already in use."
Another problem is when i try to log in with non-premium account, when i open PlaySongViewController, it will show "Spotify Premium Required" and when i close my PlaySongViewController and open another PlaySongViewController to play another song, it will be crashed again with the 'already in use' error
Can i bypass this code if i have start my spotifyPlayer?
try! spotifyPlayer?.start(withClientId: auth.clientID)
Or Are there any solutions?
Well there are two things I am seeing here:
try! spotifyPlayer?.start(withClientId: auth.clientID)
That should be a do and catch, if you look at the full signature for the start signature it states that it will throw errors. Instead make sure to catch errors when you can.
do {
try self.spotifyPlayer?.start(withClientId: auth.clientID)
} catch {
print("Failed to start with clientId")
}
It is important not force a try but instead handle errors.
You use a do-catch statement to handle errors by running a block of
code. If an error is thrown by the code in the do clause, it is
matched against the catch clauses to determine which one of them can
handle the error.
Additionally on the SPTAudioStreamingController.sharedInstance() is a property that is worth checking before the do and catch which is player?.loggedIn you can use this method to check before you attempt to call login, I've put an example of this in the singleton's login method below.
/** Returns `YES` if the receiver is logged into the Spotify service, otherwise `NO`. */
open var loggedIn: Bool { get }
Secondly you might be better off creating a singleton to handle all the logic of playing music that the View controller interfaces with so you don't end up with multiple view controllers trying to use the same spotifyPlayer and call start when it isn't necessary.
class MusicPlayer: {
static let shared = MusicPlayer()
fileprivate let player = SPTAudioStreamingController.sharedInstance()
override init() {
player?.playbackDelegate = self
player?.delegate = self
}
func login() {
if player?.loggedIn { return }
do {
try self.spotifyPlayer?.start(withClientId: auth.clientID)
} catch {
print("Failed to start with clientId")
}
}
}
and then in the view controller link to MusicPlayer.shared.
I've got a rather large body of Swift 3 code for Mac OS 10.11 and up (using Xcode 8.2.1). There are a number of processes, among them a GUI application and a background service. Both of these use a custom URLProtocol, which is implemented in a framework (imported by both application and service). The protocol sometimes may generate instances of an enum that conforms to Error, which it catches and handles appropriately (generally by using the URLProtocolClient to toss them up to the URLSession trying to make the request).
When there's no error, both the app and the service work fine.
When there is an error, the app works fine (well, as expected).
When there is an error, the service crashes.
Wandering through the debugger has shown that this crash is occurring when the Error is automatically converted into an NSError by the runtime. I added this cast explicitly in my code, and sure enough, I get the same crash, now on that line.
I saw Swift 3.1: Crash when custom error is converted to NSError to access its domain property, but it doesn't apply here:
The solution there - extending the Error to a CustomNSError (and LocalizedError for good measure) and implementing the relevant properties - didn't help.
The crash occurs after the domain has been obtained; as far as I can tell that was not a problem for me.
Possibly relevant: that was on iOS, not Mac.
Having already tried the only listed solution to that question, I'm at something of a loss. I've been debugging this for hours without getting anywhere except that it seems to happen somewhere deep in the guts of dyld.
Code:
enum CrowbarProtocolError: Error {
case FailedToCreateSocket;
case PathTooLong;
case NonSocketFile;
case SocketNotFound;
...
case UnrecognizedError(errno: Int32);
}
extension CrowbarProtocolError: LocalizedError {
public var errorDescription: String? {
return "Some localized description"
}
}
extension CrowbarProtocolError: CustomNSError {
public static var errorDomain: String {
return "Some Domain Name"
}
public var errorCode: Int {
return 204 //Should be your custom error code.
}
public var errorUserInfo: [String: Any] {
return ["WTF": "Swift?"];
}
}
...
open class CrowbarUrlProtocol: URLProtocol {
...
override open func startLoading() {
do {
let sockHandle = try CrowbarUrlProtocol.openSocket();
let req = try buildRequestData();
sockHandle.write(req);
NotificationCenter.default.addObserver(
self,
selector: #selector(self.readCompleted),
name: .NSFileHandleReadToEndOfFileCompletion,
object: nil);
sockHandle.readToEndOfFileInBackgroundAndNotify();
} catch let err {
Log.warn("CrowbarUrlProtocol request failed with error \(err)");
// -- In the background service, THIS LINE CRASHES! --
let err2 = err as NSError;
Log.warn("As NSError: \(err2)");
// -- Without the explicit cast, it crashes on this line --
self.client?.urlProtocol(self, didFailWithError: err);
}
}
...
}
One idea I have for solving this is just doing everything (or, as much as possible) using NSErrors, on the grounds that if there's never a need to convert an Error to an NSError, then whatever is causing this crash won't happen. No idea if it'll work but it seems worth a try...
OK, as far as I can tell this is just a bug in Swift's runtime, but I found a work-around: just use NSError for everything involving Obj-C code rather than Swift Errors (to avoid the implicit cast). Since I already was implementing CustomNSError, it was easy to just create a toNSError() function on my Error enum, and use that for the self.client?.urlProtocol(self, didFailWithError: err) lines.
enum CrowbarProtocolError: Error, CustomNSError {
case FailedToCreateSocket;
case PathTooLong;
...
public func asNSError() -> NSError {
return NSError(domain: CrowbarProtocolError.errorDomain,
code: self.errorCode,
userInfo: self.errorUserInfo);
}
}
...
open class CrowbarUrlProtocol: URLProtocol {
...
override open func startLoading() {
do {
let sockHandle = try CrowbarUrlProtocol.openSocket();
let req = try buildRequestData();
sockHandle.write(req);
NotificationCenter.default.addObserver(
self,
selector: #selector(self.readCompleted),
name: .NSFileHandleReadToEndOfFileCompletion,
object: nil);
sockHandle.readToEndOfFileInBackgroundAndNotify();
} catch let err as CrowbarProtocolError {
Log.warn("CrowbarUrlProtocol request failed with error \(err)");
self.client?.urlProtocol(self, didFailWithError: err.asNSError());
}
catch let err {
Log.warn("CrowbarUrlProtocol caught non-CrowbarProtocol Error \(err)");
// This would probably crash the service, but shouldn't ever happen
self.client?.urlProtocol(self, didFailWithError: err);
}
}
...
}
I have a variable in my NSViewController:
dynamic var roll_rate:Double = 0.0
I attach it to my NSTextField:
Model Key Path shows error, but it is working: When i changed value in field, variable changed too. But what means:
Validates Immediately and how do i show and check validation errors for field.
I tried implement method validateRoll_rate, but it didn't call when value changed.
Generic solution (work with or without bindings) One way of dealing with this is based on the response here
Basically you use the controlTextDidChange(notification:) delegate method of NSTextField and you implement your validation code in it.
override func controlTextDidChange (notification: NSNotification) {
guard let textField = notification.object as? NSTextField else { return }
// test here, replace the dummy test below with something useful
if textField.stringValue != "expected value" {
myTextFieldOutlet.backgroundColor = NSColor.red
myErrorLabelOutlet.stringValue = "Error !!!"
} else {
// everything OK, reset the background color and error label to the normal state
....
}
}
Obviously myTextFieldOutlet is an outlet linked to your text field and myErrorLabelOutlet is an outlet to a conveniently placed label used to show errors (blank if no error should be presented)
Bindings oriented solution Be sure Validates immediately is selected in Interface Builder and implement the following method in the class where the binding is made (Tuning View Controller in your example)
override func validateValue(_ ioValue: AutoreleasingUnsafeMutablePointer<AnyObject?>, forKey inKey: String) throws {
// test here, replace the dummy test below with something useful
if roll_rate > 10.0 {
throw NSError(domain: "your-domain", code: 100, userInfo: [NSLocalizedDescriptionKey: "Error, roll rate too high"])
}
}
When the error is thrown, the user will be presented with the standard sheet announcing the error and the option to cancel the change or correct it.
If Continuously updates value is selected in Interface Builder the method above will be called for each keystroke in the text field, otherwise only after pressing Enter or loosing focus.
Note: For a full understanding on how updating values through bindings work, including what Validates immediately does, see the docs here.
I am building an iOS app and I just finished my login/register part ( requesting a sails.js rest Api)
At the moment I have 2 view controllers with duplicate code because i issue the rest calls on register/login button event listener of each class and there is a lot of similar code I can refactor.
What I want to do is to create a singleton called ApiManager that will contain all the calls that I need. (And the futur ones )
The problem is that with async calls I can't create a function func login(username,password) that will return data so I can store them and prepareforsegue.
What is the simple/proper way to achieve that correctly? Which means call ApiManager.myFunction and using the result wherever it's needed ( filling a tableview for data, initiating a segue for login or register with succes ) and to make this function reusable in another view controller even if it is for another usage. I am using swift.
EDIT : Here is how i did it so i hope it will help you
The function executing the rest call :
func login(#username: String, password: String, resultCallback: (finalresult: UserModel!,finalerror:String!) -> Void) {
Alamofire.request(.POST, AppConfiguration.ApiConfiguration.apiDomain+"/login", parameters: ["username": username,"password": password], encoding: .JSON)
.responseJSON { request, response, data, error in
if let anError = error
{
resultCallback(finalresult: nil,finalerror:anError.localizedDescription)
}else if(response!.statusCode == 200){
var user:UserModel = self.unserializeAuth(data!)//just processing the json using SwiftyJSON to get a easy to use object.
resultCallback(finalresult: user,finalerror:nil)
}else{
resultCallback(finalresult: nil,finalerror:"Username/Password incorrect!")
}
}.responseString{ (request, response, stringResponse, error) in
// print response as string for debugging, testing, etc.
println(stringResponse)
}
}
And this is how i call this function from my ViewController :
#IBAction func onLoginTapped(sender: AnyObject) {//When my user tap the login button
let username = loginInput.text;//taking the content of inputs
let password = passwordInput.text;
ApiManager.sharedInstance.login(username:username,password:password){
[unowned self] finalresult,finalerror in
if(finalresult !== nil){//if result is not null login is successful and we can now store the user in the singleton
ApiManager.sharedInstance.current_user=finalresult
self.performSegueWithIdentifier("showAfterLogin", sender: nil)//enter the actual app and leave the login process
}else{
self.displayAlert("Error!", message: finalerror)//it is basically launching a popup to the user telling him why it didnt work
}
}
}
Almost all of my apps end up with a Server class which is the only one that knows how to communicate with the server. It makes the call, parses the result into a Swift struct and returns it. Most of my servers return json so I use SwiftyJSON, but you can do whatever you want.
The point is, that since this is the only class that knows about server communication, if I need to change the library being used to do the communication (AFNetworking 1 vs 2 vs Parse, vs whatever) this is the only class I need to touch.
class Server {
static let instance = Server()
func loginWithUsername(username: String, password: String, resultCallback: (result: Either<User, NSError>) -> Void) {
// if login is successful call
resultCallback(result: .Left(self.user!))
// otherwise call
resultCallback(result: .Right(error))
}
}
An example of use:
let server = Server.instance
SVProgressHUD.showWithStatus("Loggin In...")
server.loginWithUsername(username, password: password) { [unowned self] result in
SVProgressHUD.dismiss()
switch result {
case .Left(let user):
self.presentUserType(user.userType)
case .Right(let error):
self.warnUserWithMessage("An error occured. \(error.localizedDescription)")
}
}
If the username/password are needed for all subsequent calls, then the server object will maintain a copy of them. If the login returns a token, then the server keeps a copy of that.
QED.
I usually have utility functions in a base class shared by my view controllers and use NSNotificationCenter for reacting to the results of the requests. It can also easily be achieved through delegation (protocol & delegate.
It is mostly about perception but I find it is easier to visualize that you can, for example, start an action on one controller and react on another because the call took this long and you were not blocking navigation in your app.