Fetch User Data
The Facebook SDK for iOS includes convenience methods to access the Graph API User object. It also supports strongly-typed access to common User properties.
The FBRequestConnection class method startForMeWithCompletionHandler: can be used to initiate a Graph API call for user data. This is essentially a call to the /me Graph API endpoint. The permissions in the access_token that are sent with the API call control the returned data (ex: if no access token is provided, only public info will be returned). See the User doc for more details on User properties and permissions.
If the API call returns successfully, the startForMeWithCompletionHandler: completion handler gets result data that conforms to the FBGraphUser protocol. This provides typed access to the following fields: id, name, first_name, middle_name, last_name, link, username, birthday and location. You have access to other user properties with NSDictionary and NSArray methods on the result data.
This doc outlines how to use the SDK to request user data and retrieve user details for fields available via typed access and non-typed access.
This document walks through the following:
- Prerequisites
- Sample Overview
- Step 1: Set Up the UI
- Step 2: Ask for Permissions
- Step 3: Fetch User Data
- Troubleshooting
- Additional Info
Prerequisites
Before you begin, make sure you set up Facebook Login. This ensures you have the prerequisites and your app is ready for additional Facebook integration.
Sample Overview
The completed sample lets users log in with Facebook and view a sample set of their data, including their name, birthday, current city and languages. This data illustrates the following combinations:
- Data that needs permissions other than basic permission
- Data that is strongly typed through the
FBGraphUserprotocol - Data that is not strongly typed through the
FBGraphUserprotocol
The sample builds on top of Facebook Login, adding a non-editable text area that displays the returned user data:
Step 1: Set Up the UI
In this step, you'll add the text view that displays the user data.
Open the main nib file and add the text view:
- Add a
Text Viewobject to the view. Stretch it across the screen and as far down as you can. - In the Attributes Inspector, clear the text.
- Hide the text view initially. You only want to display it after the user authenticates.
- Ensure the text field is not editable, as you're only using it to display data. Deselect the behavior's
Editablecheckbox. - Add an outlet to your view controller's implementation file so it's private. Name the outlet ''userInfoTextView''.
When you've completed this step, your implementation file should have one new outlet.
If you followed the Facebook Login doc, you should have a sessionStateChanged: method defined in your view controller implementation file that controls the logged-in and logged-out UI. Modify this method to only show the text view when the user is authenticated:
- (void)sessionStateChanged:(NSNotification*)notification {
if (FBSession.activeSession.isOpen) {
[self.authButton setTitle:@"Logout" forState:UIControlStateNormal];
self.userInfoTextView.hidden = NO;
} else {
[self.authButton setTitle:@"Login" forState:UIControlStateNormal];
self.userInfoTextView.hidden = YES;
}
}
Step 2: Ask for Permissions
In this step, you'll configure your app to ask for permissions to display the sample set of user data. You'll ask for user_location to get the user's current city, user_birthday to get their birthday, and user_likes to get their languages. The other user data you'll display are available publicly or with basic permissions.
If you followed the Facebook Login doc, you should have a openSessionWithAllowLoginUI: method defined in your app delegate implementation file. Open the app delegate implementation file and modify the FBSession initialization section to request additional permissions:
- (BOOL)openSessionWithAllowLoginUI:(BOOL)allowLoginUI {
NSArray *permissions = [[NSArray alloc] initWithObjects:
@"user_location",
@"user_birthday",
@"user_likes",
nil];
return [FBSession openActiveSessionWithReadPermissions:permissions
allowLoginUI:allowLoginUI
completionHandler:^(FBSession *session,
FBSessionState state,
NSError *error) {
[self sessionStateChanged:session
state:state
error:error];
}];
}
Step 3: Fetch User Data
In this step, you'll fetch the user info when the user authenticates. Again, the user data you can access depends on the permissions a user has granted your app along with the data a user has chosen to share with apps. To get an idea of the data you can access, here's an example Graph API raw response for the permissions in the previous step:
{
bio = "Love sports of all kinds.";
birthday = "01/01/1980";
"favorite_athletes" = (
{
id = 20242388857;
name = "Usain Bolt";
}
);
"first_name" = Chris;
hometown = {
id = 106033362761104;
name = "Campbell, California";
};
id = 100003086810435;
languages = (
{
id = 108106272550772;
name = French;
},
{
id = 312525296370;
name = Spanish;
}
);
"last_name" = Colm;
link = "http://www.facebook.com/chris.colm";
locale = "en_US";
location = {
id = 104048449631599;
name = "Menlo Park, California";
};
"middle_name" = Abe;
name = "Chris Abe Colm";
timezone = "-7";
"updated_time" = "2012-08-09T03:33:32+0000";
username = "chris.colm";
verified = 1;
}
Some of the data in this response can be accessed as strongly typed properties of the properties of the FBGraphUser protocol - example: name and birthday. Other properties can be accessed by selecting a key from the appropriate NSDictionary - example: locale and languages. This step shows you how to access the user's name, birthday, languages, location and locale.
Modify the sessionStateChanged: method to do this:
...
if (FBSession.activeSession.isOpen) {
[self.authButton setTitle:@"Logout" forState:UIControlStateNormal];
self.userInfoTextView.hidden = NO;
[FBRequestConnection
startForMeWithCompletionHandler:^(FBRequestConnection *connection,
id<FBGraphUser> user,
NSError *error) {
if (!error) {
NSString *userInfo = @"";
// Example: typed access (name)
// - no special permissions required
userInfo = [userInfo
stringByAppendingString:
[NSString stringWithFormat:@"Name: %@\n\n",
user.name]];
// Example: typed access, (birthday)
// - requires user_birthday permission
userInfo = [userInfo
stringByAppendingString:
[NSString stringWithFormat:@"Birthday: %@\n\n",
user.birthday]];
// Example: partially typed access, to location field,
// name key (location)
// - requires user_location permission
userInfo = [userInfo
stringByAppendingString:
[NSString stringWithFormat:@"Location: %@\n\n",
[user.location objectForKey:@"name"]]];
// Example: access via key (locale)
// - no special permissions required
userInfo = [userInfo
stringByAppendingString:
[NSString stringWithFormat:@"Locale: %@\n\n",
[user objectForKey:@"locale"]]];
// Example: access via key for array (languages)
// - requires user_likes permission
if ([user objectForKey:@"languages"]) {
NSArray *languages = [user objectForKey:@"languages"];
NSMutableArray *languageNames = [[NSMutableArray alloc] init];
for (int i = 0; i < [languages count]; i++) {
[languageNames addObject:[[languages
objectAtIndex:i]
objectForKey:@"name"]];
}
userInfo = [userInfo
stringByAppendingString:
[NSString stringWithFormat:@"Languages: %@\n\n",
languageNames]];
}
// Display the user info
self.userInfoTextView.text = userInfo;
}
}];
Build and run the project to make sure it runs without errors. Tap the ''Login'' button to log in with Facebook.
During the authentication step, you should see a dialog asking for the permissions you requested. Once authenticated, you should see the sample set of user data. Try displaying other user properties and become familiar with the required permissions.
Troubleshooting
If you have any issues fetching user data, enable HTTP request logging by adding this code before requesting user data:
[FBSettings setLoggingBehavior:[NSSet setWithObjects:
FBLoggingBehaviorFBRequests, nil]];
This will log details about HTTP requests and response to the output pane in Xcode.
Additional Info
Scrumptious: sample included in the SDK that shows an example of getting user info.- Handling Facebook API Errors: Graph API topic on error handling
- User: Graph API User documentation.
Updated about 4 months ago