User Authentication

The Log in with Twitter feature enables app users to authenticate with Twitter.

Note

If you’re not using Fabric’s auto-generated Twitter credentials, ensure that “Allow this application to be used to Sign in to Twitter” is checked for your Twitter app before using this feature.

The SDK first attempts to leverage system Twitter accounts, via Accounts.framework. If that fails, it falls back to presenting an OAuth flow. After successful authentication, the SDK automatically saves the account to iOS system accounts and the TWTRSession will contain a token, secret, username, and user ID of the user. If authentication fails, the error will be non-nil.

User authentication is required for API requests that require a user context, for example: Tweeting or following other users.

Log in Button

The simplest way to authenticate a user is using TWTRLogInButton:

// Objective-C
TWTRLogInButton* logInButton =  [TWTRLogInButton
                                     buttonWithLogInCompletion:
                                     ^(TWTRSession* session, NSError* error) {
    if (session) {
         NSLog(@"signed in as %@", [session userName]);
    } else {
         NSLog(@"error: %@", [error localizedDescription]);
    }
}];
logInButton.center = self.view.center;
[self.view addSubview:logInButton];

// Swift
let logInButton = TWTRLogInButton(logInCompletion:
        { (session, error) in
            if (session != nil) {
                println("signed in as \(session.userName)");
            } else {
                println("error: \(error.localizedDescription)");
            }
})
logInButton.center = self.view.center
self.view.addSubview(logInButton)

This will render a button that looks like:

Log in Method

// Objective-C
[[Twitter sharedInstance] logInWithCompletion:^
            (TWTRSession *session, NSError *error) {
  if (session) {
      NSLog(@"signed in as %@", [session userName]);
  } else {
      NSLog(@"error: %@", [error localizedDescription]);
  }
}];

// Swift
Twitter.sharedInstance().logInWithCompletion { 
                (session, error) -> Void in
    if (session != nil) {
        println("signed in as \(session.userName)");
    } else {
        println("error: \(error.localizedDescription)");
    }
}

Guest Authentication

To use the SDK without requiring user authentication first, you will need to log in as a guest. Guest authentication is limited to API requests that do not require a user context. This means, for example, that you cannot Tweet with guest authentication. You can get a user’s timeline of public Tweets.

Guest authentication is an extension to application authentication and as such, the permission scope and rate limits are the same as application authentication. There are however two major differences:

1. rate limits will scale with the number of users of your application
2. guest auth tokens have a time expiration

To obtain a guest token for your user, you can call the following method:

// Objective-C
[[Twitter sharedInstance] logInGuestWithCompletion:^(TWTRGuestSession *guestSession, NSError *error) {
  if (guestSession) {
    // make API calls that do not require user auth
  } else {
      NSLog(@"error: %@", [error localizedDescription]);
  }
}];

// Swift
Twitter.sharedInstance().logInGuestWithCompletion { guestSession, error in
    if (guestSession != nil) {
      // make API calls that do not require user auth
    } else {
        println("error: \(error.localizedDescription)");
    }
}

We will automatically retry once on token expiration in TwitterKit. Additionally, here is a sample snippet you can use to detect a timeout and trigger a retry manually.

// Objective-C
[[[Twitter sharedInstance] APIClient] loadTweetWithID:@"20" completion:^(TWTRTweet *tweet, NSError *error) {
  if (error.domain == TWTRAPIErrorDomain && (error.code == TWTRAPIErrorCodeInvalidOrExpiredToken || error.code == TWTRAPIErrorCodeBadGuestToken)) {
    // can manually retry by calling -[Twitter logInGuestWithCompletion:]
  }
}];

// Swift
Twitter.sharedInstance().APIClient.loadTweetWithID("20") { tweet, error in
  if error.domain == TWTRAPIErrorDomain && (error.code == .InvalidOrExpiredToken || error.code == .BadGuestToken) {
    // can manually retry by calling Twitter.sharedInstance().logInGuestWithCompletion
  }
}