Tag Friends in Facebook Photo Upload - objective-c

Question

I'd like to be able to tag existing friends using the graph api:
Here's the code I have at the moment. The photo is being uploaded, but the photo isn't tagging the user specified in the user_id:
UIImage *testImage = [UIImage imageNamed:#"sendingTo"];
NSMutableDictionary *params = [NSMutableDictionary dictionaryWithObjectsAndKeys:kFacebookFBConnectAppID, #"app_id",
testImage, #"source",
#"1381470076", #"message_tags",
#"TEST!", #"message", nil];
[self.socialIntegration.facebook requestWithGraphPath:[NSString stringWithFormat:#"/me/photos?access_token=%#", self.socialIntegration.facebook.accessToken]
andParams:params
andHttpMethod:#"POST" andDelegate:self];
Is the message_tags attribute not the correct attribute to use?
Thanks!
EDIT
From what I see here (https://developers.facebook.com/docs/reference/api/photo/#tags), it looks like I need to make three calls in total:
Post the Photo with the code I already have
Ask Facebook to give me the ID of this photo (which i can probably get from the FBRequestDelegate)
Tag People after posting.

Answer 1

ok, figured it out.
Here's how you do it.
First, you upload the image.
UIImage *testImage = [UIImage imageNamed:#"sendingTo"];
NSMutableDictionary *params = [NSMutableDictionary dictionaryWithObjectsAndKeys:kFacebookFBConnectAppID, #"app_id",
testImage, #"source",
#"TEST!", #"message", nil];
[self.socialIntegration.facebook requestWithGraphPath:[NSString stringWithFormat:#"/me/photos?access_token=%#", self.socialIntegration.facebook.accessToken]
andParams:params
andHttpMethod:#"POST" andDelegate:self];
Next, upon successful upload, the - (void)request:(FBRequest *)request didLoad:(id)result method will return a dictionary result with 1 key id. That ID is the photoID of the photo you just uploaded, which you save into a string:
NSString *photoID = [NSString stringWithFormat:#"%#", [(NSDictionary*)result valueForKey:#"id"]];
Then make another GraphAPI request to tag your friends. In the code below I am tagging one specific friends, but to tag multiple friends use CSV string or array:
[self.socialIntegration.facebook requestWithGraphPath:[NSString stringWithFormat:#"%#/tags/%#?access_token=%#", photoID, #"1381470076", self.socialIntegration.facebook.accessToken]
andParams:nil
andHttpMethod:#"POST" andDelegate:self];