Twitter Integration

I previously wrote about Facebook Connect. However, Facebook is not the only social network out there. Twitter is another popular network.

The implementation process is similar to Facebook Connect. I will list the steps:

1. Register your app with Twitter.
2. Download and copy MGTwitterEngine into your source code.
3. Create an MGTwitterEngineDelegate and an MGTwitterEngine object.
4. Create your own login page for Twitter.
5. Pass the user’s credentials to MGTwitterEngine.
6. Authenticate the user’s credentials.
7. Start tweeting!

To start, you will need to register your app with Twitter. This can be done at http://dev.twitter.com/. This is also where you will find all of the API documentation and other information. Unlike Facebook, only one user can be a developer for a particular app. So, you may want to create a Twitter account specific to your app or company to handle the development of your Twitter features.

Another point to note is that after June 30, 2010 your app will have to use OAuth (or xAuth) for authentication. I won’t go into the details here. Consult the Twitter documentation for details.

Now you can start implementing Twitter into your app. Unfortunately, Twitter doesn’t have a convenient Xcode project to use. This will require using some third-party software. I used MGTwitterEngine. It is produced by @mattgemmell. His code can be found at http://mattgemmell.com/.

MGTwitterEngine revolves around the use of the MGTwitterEngine object. This isn’t nearly as advanced as Facebook Connect. You will have to handle the login dialog and automatic re-login on your own. A user’s credentials can be securely stored in the iPhone’s keychain. Details on the keychain can be found in the iPhone API.

Logging in takes several steps. You will first need to create an MGTwitterEngineDelegate before creating an MGTwitterEngine object. Once you have prompted the user for their user name and password, this can be passed on to MGTwitterEngine by the following method:
[twitterEngine setUsername:(NSString *)name password:(NSString *)password];
However, this does not authenticate the user name and password. It simply stores them in the MGTwitterEngine. Verification can be received by calling:
[twitterEngine checkUserCredentials];
This will make a call to the API to verify the user’s credentials. This method does not wait for the verification to return. Instead, one of two MGTwitterEngineDelegate methods will be called when the verification returns. These two delegate methods are:
- (void) requestSucceeded:(NSString *)requestIdentifier
- (void) requestFailed:(NSString *)requestIdentifier withError:(NSError *)error
Since these calls occur asynchronously, you will need to handle this accordingly. Some options include blocks, GCD, and/or how ever else you want to handle it.

From here you are ready to start using Twitter from your app. MGTwitterEngine provides several methods for doing various actions. One you will likely use is
[twitterEngine sendUpdate:@“Hello World!”];
This will send a tweet as you would expect. Remember to keep tweets to 140 characters.

Your now ready to make Twitter a part of your apps. Happy Tweeting!