Allow iOS app user to authenticate with Facebook only when NECESSARY - ios

Question

I have an iPhone app that allows users to record videos and I'd like them to be able to share those videos on Facebook.
However, unless the user decides to share, I don't want him/her to be redirected to Facebook. I've tried the method provided in the Facebook iOS tutorial, and it requires the user to be redirected to Facebook and authenticate as soon as the app starts up.
That's unnecessary.
What I'd like to do is have a "Share" button that allows the user to authenticate and then automatically upload a video right afterward using the POST request.
Is this possible? Has anyone achieved a similar effect?
Thanks.

Answer 1

I'm not sure which tutorial you're looking at, but it probably has you authenticate at launch just as a demo.
In your app, you can authorize you app with something like this after the video is saved
// Share button action
- (IBAction)sharePressed {
// If user is already authenticated
if ([facebook isSessionValid]) {
[self shareLinkToFacebook];
} else {
// Authenticate with just email permissions
NSArray* permissions = [NSArray arrayWithObjects:
#"email", nil];
[facebook setSessionDelegate:self];
[facebook authorize:permissions];
}
}
- (void) shareLinkToFacebook {
// Create a simple post
NSMutableDictionary *params = [[NSMutableDictionary alloc] init];
[params setValue:[video url] forKey:#"link"];
[params setValue:[video title] forKey:#"name"];
[params setValue:#"description" forKey:#"description"];
[facebook dialog:#"feed" andParams:params andDelegate:self];
}
// FBSessionDelegate
- (void) fbDidLogin {
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:[facebook accessToken] forKey:kFBAccessToken];
[defaults setObject:[facebook expirationDate] forKey:kFBExpirationDateKey];
[defaults synchronize];
[self shareLinkToFacebook];
}
You're going to have to authenticate with facebook to get an access key- there's no way around that.

Answer 2

You cannot do what you want. To publish something, you must have a valid access_token. the only way to achieve this is to follow the login procedure that you saw in the official example.

Answer 3

The answer to this question lies in creating a singleton that operates as both the FBSessionDelegate and the FBRequestDelegate, and allows you to pass one instance of Facebook around your program.
I called my singleton FacebookVideoUploader, and in my app delegate I called:
- (BOOL)application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(NSString *)sourceApplication annotation:(id)annotation {
return [[[FacebookVideoUploader sharedInstance] facebook] handleOpenURL:url];
That's it. This keeps the app delegate uncluttered and let's the singleton handle the delegate methods.
In my implementation file for my view controller that handles the video upload I put:
(IBAction)shareWithFacebook:(UIButton *)sender {
[[FacebookVideoUploader sharedInstance] postVideoToFacebook];
}
That's it. All of the delegate and session methods as well as postVideoToFacebook are handled in the FacebookVideoUploader singleton.
This allows my users to log into my app without being redirected to Facebook and lets them authenticate as soon as they decide they want to share a video.