Posting message to facebook wall using iPhone SDK

UPDATE: I have posted my sample application code here. Please visit code fore more information.

Recently I was working on iPhone project that required to post message on Facebook wall.

There is already official facebook API for iOS SDK, which we can use for interacting with Facebook.

You can download Facebook API from GitHub repository using following command.
git clone git://github.com/facebook/facebook-ios-sdk.git

To use downloaded facebook API, you need to bring all facebook API source code under your project. To do this you can just drag it's src folder and drop it under your project in XCode.

Before you start coding, you need a valid facebook application id, you can get one from Developer App. And you need to add this App ID in "fbYOUR_APP_ID" format to your project's .plist file like shown in following snapshot.

Now you are ready to use Facebook iPhone SDK. Main interface class to invoke Facebook API is "Facebook". Following is code to use Facebook class to login and autorize application to use user's facebook account.

facebook = [[Facebook alloc] initWithAppId:@"YOUR_APP_ID"];
   NSArray* permissions =  [NSArray arrayWithObjects:@"read_stream", 
    @"publish_stream", nil];
   [facebook authorize:permissions delegate:self];

With read_stream we can access user's basic account information and with publish_stream we can post to user's wall and make comment.

To authorization to complete successfully we need to implement application:handleOpenURL: method from UIApplicationDelegate and forwad call to facebook API. Like shown in below code.

return [facebook handleOpenURL:url]; 

So everything goes fine then you should be able to retrieve user's account information and post to user's wall as well.

Now to post message to user's wall you can use following code.

NSMutableDictionary* params = [[NSMutableDictionary alloc] 
initWithCapacity:1]
 [params setObject:@"Testing" forKey:@"name"];
 [params setObject:@"IMAGE_URL" forKey:@"picture"];
 [params setObject:@"Description" forKey:@"description"];
 [facebook requestWithGraphPath:@"me/feed" 
        andParams:params 
    andHttpMethod:@"POST" 
      andDelegate:self];

Here "me/feed" is used to post message to logged in user's wall, if you want to post to some other user's wall using logged in user's account then use need to use "USER_ID/feed" instead.