Don't upload API Keys to Git

If you have a public repository you might want to hide your Google Sign-In Client ID.

Instead of hardcoding API keys into Info.plist or AppDelegate, they can be hidden in many ways, so they are not available in your repo.

Open the xcconfig files of your project.

MyVocabulary/Pods/Target\ Support\ Files/Pods-MyVocabulary/Pods-MyVocabulary.release.xcconfig
MyVocabulary/Pods/Target\ Support\ Files/Pods-MyVocabulary/Pods-MyVocabulary.debug.xcconfig

Append REVERSED_CLIENT_ID and CLIENT_ID at the end of both files (the name of the variables can be modified).

GOOGLE_SIGN_IN_REVERSED_CLIENT_ID=com.googleusercontent.apps.xxxxxxxxxxxxx
GOOGLE_SIGN_IN_CLIENT_ID=xxxxxxxxxxxxx.apps.googleusercontent.com

You don’t want to upload these changes to your repo, so before doing git add of those files, you must indicate that changes in those files must not be taken into consideration.

git update-index --assume-unchanged MyVocabulary/Pods/Target\ Support\ Files/Pods-MyVocabulary/Pods-MyVocabulary.debug.xcconfig
git update-index --assume-unchanged MyVocabulary/Pods/Target\ Support\ Files/Pods-MyVocabulary/Pods-MyVocabulary.release.xcconfig

Note: If later you want to make changes into xcconfig files and upload them into your repo, remember to revert this.

git update-index --no-assume-unchanged <file>

Now, the variables can be used in the Info.plist doing $(GOOGLE_SIGN_IN_CLIENT_ID) and $(GOOGLE_SIGN_IN_REVERSED_CLIENT_ID). Please, when adding the new URLTypes, give them an unique identifier.

We are almost there… Remember that the client ID was needed in the AppDelegate to be set into GIDSignIn.sharedInstance().clientID? I made an extension of Bundle that obtains URLType’s URL Schemes giving its identifier (see the previous step).

extension Bundle {
    static func urlScheme(urlTypeId: String) -> String? {
        (((main.infoDictionary?["CFBundleURLTypes"] as? [[String: Any]])?
            .first(where: { $0["CFBundleURLName"] as? String == urlTypeId}))?["CFBundleURLSchemes"] as? [String])?.first
    }
}

Instead of hardcoding the API key in the AppDelegate…

GIDSignIn.sharedInstance().clientID = Bundle.urlScheme(urlTypeId: "GOOGLE_SIGN_IN_CLIENT_ID")