What is deep linking?
Deep linking basically enables you to open an app from another app or a website while passing on parameters. This mechanism works with custom URL schemes which you can define in the .plist of your app.
Why deep linking?
If you have an app with lookup functionality (e.g. an app for finding song lyrics) you might want to perform a lookup without having to navigate to the designated screen and typing in the query. This can be achieved by opening the following example URL MyAppScheme://myAction=lookup&myQuery=What%20is%20the%20meaning%20of%20life in another app of the browser. In this case the app is programmed to read the ‘myAction’-parameter on startup to determine the action and the ‘myQuery’-parameter for the search query. Often, deep linking doesn’t go as planned and you might need to debug your app.
Why is debugging this difficult?
Deep linking might occur in three kinds of scenarios:
- The app hasn’t been installed yet
- The app is running in the background (or foreground for that matters)
- The app is installed but not running at all
Scenario 1 is irrelevant in this case, so we’ll skip this one. Scenario 2 should be no problem since the app is running on the device (or simulator) while in a debug session. Scenario 3 requires you not to have the app running, but you need the debug session to be able to debug. This is a problem because Xcode starts the app automatically when starting a debug session. Instead of letting Xcode start the app, you want to do it yourself using the deep link URL.
So… tell me how to do this
There is a convenient option which enables you to start a debug session by manually starting the app. To achieve this, go to the ‘Edit scheme’ screen and tick the ‘Wait for MyApp.app to be launched manually’ option on in the ‘Run’ configuration.
Whenever you run the target in Xcode, the app doesn’t automatically starts and the debug session will only start when you manually start the app.
So start kicking some bugs ass!