Basic actions with FBSDK 4.x

BasicExamplesFBSDK.m

//
// Login via FBSDK
//
- (void)connectFacebookAccountWithCompletionHandler:(void (^)(NSError *))completionHandler
{
    NSArray *readPermissions = @[@"public_profile", @"user_friends", @"email", @"user_likes"];
    
    if (![FBSDKAccessToken currentAccessToken]) {
        FBSDKLoginManager *login = [[FBSDKLoginManager alloc] init];
        [login logInWithReadPermissions:readPermissions
                     fromViewController:nil // TODO: provide a VC
                                handler:^(FBSDKLoginManagerLoginResult *result, NSError *error) {
            [self fbLoginManagerLoginResult:result
                         didChangeWithError:error];
            
            if (completionHandler) {
                completionHandler(error);
            }
        }];
    }
    
    else {
        if (completionHandler) {
            completionHandler(nil);
        }
    }
}

// 
// Process FB Login response
//
- (void)fbLoginManagerLoginResult:(FBSDKLoginManagerLoginResult *)result didChangeWithError:(NSError *)error
{
    if (error) {
        CLS_LOG(@"FB auth error %@", [error detailedInfo]);
        // Notify about error
    }
    else if (result.isCancelled) {
        CLS_LOG(@"FB auth cancelled");
        [self logoutFacebook];
    }
    else {
        // check if specific permissions missing
        if (![result.grantedPermissions containsObject:@"user_likes"]) {
            CLS_LOG(@"\"user_likes\" FB permissions are missing");
        }
        
        CLS_LOG(@"login");
        // do login with your server, if needed
    }
}
//
// Logout FB
//
- (void)logoutFacebook
{
    if ([FBSDKAccessToken currentAccessToken]) {
        [[FBSDKLoginManager new] logOut];
    }
}
//
// get FB Profile
//
if ([FBSDKAccessToken currentAccessToken]) {
    FBSDKGraphRequest *request = [[FBSDKGraphRequest alloc] initWithGraphPath:@"me"
                                                                   parameters:nil];
    [request startWithCompletionHandler:^(FBSDKGraphRequestConnection *connection, id result, NSError *error) {
        if (!error) {
              NSDictionary* user = (NSDictionary *)result;
              // [user objectForKey:@"name"]
              // [user objectForKey:@"id"]
        }
    }];
}