UIApplication.sharedApplication.open() doesn't load url

Question

I'm working with Swift 3 and Xcode 8 (iOS 10.1), I'm completely new to the whole world. :)

I'm authenticating against an external app to get an access token. The use case is:

1) Load external app from my app

2) Validate the user and get the access token

3) Redirect back to my app from external app

I am able to do 1) and 2), but not 3). The external app has specified that you configure a redirect parameter, and I've done that. But alas, no cigar.

I have set up URL schemes in Info.plist for both apps. I don't get any errors in the console or debugger.

I have been googling and researching for the past 4 days and this is the solution I have come up with so far. Right now, I see the console messages, but the external app is no longer opening up.

AppDelegate

  func application(_ app: UIApplication, open url: URL, options: [UIApplicationOpenURLOptionsKey : Any] = [:]) -> Bool {
    if (url.scheme == "extapp") {
        print("working with extapp scheme")
    } else if (url.scheme == "myapp") {
        print("redirecting back to app after working with extapp")
    }
    return true
  }

ViewController

@IBAction func loginButton(_ sender: Any) {
    let id = text.text
    let currentCharacterCount = id.text?.characters.count ?? 0
    if currentCharacterCount == 0 {
        self.showAlert(text: "Please provide a id.")
    } else if currentCharacterCount < 10 {
        self.showAlert(text: "Oh! id doesn't seem to be in the correct format. Try again.")
    } else {
        if (self.firebaseData.callAuth(loggedIn: id!)) {
            OpenExtApp()
        }
    }
}

func OpenExtApp() {
    let Url = URL(string: "extapp:///?autostart=\(token)&redirect=myapp://key")
    if (UIApplication.shared.canOpenURL(Url!)) {
        UIApplication.shared.open(Url!, options: [:])
    }
}

I would really appreciate your help in any way.

Is it goes inside if block?, put break point and check once. — Nirav D, Nov 17 '16 at 12:48
@NiravD you mean, in the AppDelegate code or ViewController? — Mina, Nov 17 '16 at 12:50
Yes, it does. Is there a way to see what error/success is returned from the open method? I couldn't find anything online about this. — Mina, Nov 17 '16 at 12:57
try to type myapp://key in safari browser to ensure your app can be opened from the url schema. If it is ok, Probably the error is in ext app part. Maybe need to encode your myapp://key url so that external app can read it correctly. — Surely, Nov 17 '16 at 14:17
@Surely I can open the app from Safari. I will try encoding. Which option do I use in `addingPercentEncoding`? I have tried it before with .urlAllowHost, but it didn't help/work. — Mina, Nov 17 '16 at 14:22
@Anand that didn't work, it opened up Safari rather than the extapp. — Mina, Nov 18 '16 at 08:57

score 1 · Accepted Answer · answered Nov 18 '16 at 16:00

The problem appears to have been with the addingPercentEncodingmethod I was using to encode the redirect parameter. I didn't notice that the parameter wasn't being encoded properly. It turns out that the default filter in with AllowedCharacters doesn't encode / and :. It's a known issue with Apple. This solved the encoding problem and, in turn, the problem I was having with opening the extapp:

let characterSetTobeAllowed = (CharacterSet(charactersIn: "!*'();:@&=+$,/?%#[] ").inverted)
let redirect = parameter.addingPercentEncoding(withAllowedCharacters: characterSetTobeAllowed)

score 0 · Answer 2 · edited May 23 '17 at 12:13

0

Check this out and also make sure to add the custom schemes to your info.plist file How to handle custom url schemes in swift (XCode 8)?

edited May 23 '17 at 12:13

Community

1
1

answered Nov 17 '16 at 21:18

Ahmed

938
7
16

thanks for your answer, Ahmed. My method signature in AppDelegate is as what is specified in the link you provided. – Mina Nov 18 '16 at 08:59

UIApplication.sharedApplication.open() doesn't load url

2 Answers2