Open FBSession with existing token data in iOS

Question

I have a backend service that will register me in my application and return the extended facebook token from the previous login, possibly from another device (therefore, no credentials are cached on this device). I want to use this token to start a Facebook session. I am using something like:

FBSession* session = [[FBSession alloc] initWithPermissions:@[@"publish_actions"]]; FBAccessTokenData* tokenData = [FBAccessTokenData createTokenFromString:token permissions:@[@"publish_actions"] expirationDate:nil loginType:FBSessionLoginTypeTestUser refreshDate:nil]; [session openFromAccessTokenData:tokenData completionHandler:nil]; 

I pass 'nil' here for clarity, in my code I handle the completion and output the returned session object, which appears to be in the Open state without errors. When I try to use a session, I get an error message:

 Error Domain=com.facebook.sdk Code=5 "The operation couldn't be completed. (com.facebook.sdk error 5.)" UserInfo=0xb8b1680 {com.facebook.sdk:HTTPStatusCode=403, com.facebook.sdk:ParsedJSONResponseKey={ body = { error = { code = 200; message = "(#200) The user hasn't authorized the application to perform this action"; type = OAuthException; }; }; code = 403; }, com.facebook.sdk:ErrorSessionKey=<FBSession: 0xa2b62a0, state: FBSessionStateOpen, loginHandler: 0xa29e9b0, appID: 131721883664256, urlSchemeSuffix: , tokenCachingStrategy:<FBSessionTokenCachingStrategy: 0xa273f60>, expirationDate: 4001-01-01 00:00:00 +0000, refreshDate: 2013-07-26 16:21:10 +0000, attemptedRefreshDate: 0001-12-30 00:00:00 +0000, permissions:( email, "publish_actions" )>} 

Any suggestions...?

Answer 1

I found a solution: (if you have an existing token)

The first subclass of the FBSessionTokenCachingStrategy class is MySessionTokenCachingStrategy and overrides the method below:

 - (FBAccessTokenData *)fetchFBAccessTokenData { NSMutableDictionary *tokenInformationDictionary = [NSMutableDictionary new]; // Expiration date tokenInformationDictionary[@"com.facebook.sdk:TokenInformationExpirationDateKey"] = [NSDate dateWithTimeIntervalSinceNow: 3600]; // Refresh date tokenInformationDictionary[@"com.facebook.sdk:TokenInformationRefreshDateKey"] = [NSDate date]; // Token key tokenInformationDictionary[@"com.facebook.sdk:TokenInformationTokenKey"] = self.token; // Permissions tokenInformationDictionary[@"com.facebook.sdk:TokenInformationPermissionsKey"] = self.permissions; // Login key tokenInformationDictionary[@"com.facebook.sdk:TokenInformationLoginTypeLoginKey"] = @0; return [FBAccessTokenData createTokenFromDictionary: tokenInformationDictionary]; } 

Then use the class above to create

 MySessionTokenCachingStrategy* tokenCachingStrategy = [[MySessionTokenCachingStrategy alloc] initWithToken:token andPermissions:@[@"read_stream"]]; FBSession *session = [[FBSession alloc] initWithAppID: nil permissions: @[@"read_stream"]] urlSchemeSuffix: nil tokenCacheStrategy: tokenCachingStrategy]; if (session.state == FBSessionStateCreatedTokenLoaded) { // Set the active session [FBSession setActiveSession: session]; // Open the session, but do not use iOS6 system acount login // if the caching strategy does not store info locally on the // device, otherwise you could use: // FBSessionLoginBehaviorUseSystemAccountIfPresent [session openWithBehavior: FBSessionLoginBehaviorWithFallbackToWebView completionHandler: ^(FBSession *session, FBSessionState state, NSError *error) { if (!error) { if (session.isOpen) { successBlock(); } } else { failureBlock([error description]); } }]; } 

Answer 2

Is this due to the fact that you first need reading rights, and only then can you ask someone else?

Answer 3

You are executing [[FBSession alloc] initWithPermissions:@[@"publish_actions"]] , which means your session will request and "have" permissions for publish_actions , but look at the token from your error:

 com.facebook.sdk:ErrorSessionKey=<FBSession: 0xa2b62a0, state: FBSessionStateOpen, loginHandler: 0xa29e9b0, appID: 131721883664256, urlSchemeSuffix: , tokenCachingStrategy:<FBSessionTokenCachingStrategy: 0xa273f60>, expirationDate: 4001-01-01 00:00:00 +0000, refreshDate: 2013-07-26 16:21:10 +0000, attemptedRefreshDate: 0001-12-30 00:00:00 +0000, permissions:( email, "publish_actions" ) 

Your token already has email permissions. Do you think it could be a problem?

Try creating an instance using [[FBSession alloc] initWithPermissions:@[@"publish_actions", @"email"]] and see if you have problems.