无法使用通过电子邮件/密码的Firebase简单登录来执行完成阻止

Question

So I'm new to using Firebase, and iOS app development, and am trying to set up Simple Login following this guide.

For some reason though the completion block code never gets executed and a bool that i'm using to see if the user creation went okay is always NO. I tried to step through my code using the Debugger and when it got to the completion block it basically just jumped to the end of the method, very odd behavior. Here is my code:

BOOL goodFirebaseCall = false;

- (void)createUser:(NSString*)userName andPasswordis:(NSString*)password {

  goodFirebaseCall = [self createFirebaseUser:userName andPasswordis:password];

  if(goodFirebaseCall==true) //goodFirebaseCall is always NO
  {
      NSLog(@"Logged in, now adding the user to Firebase.");
      // Create a reference to a Firebase location
      Firebase* fUsers = [[Firebase alloc]    initWithUrl:@"https://xxxx.firebaseio.com/users"];

      Firebase* fNewUser = [fUsers childByAppendingPath:userName]; //childByAutoId];
      [fNewUser setValue:@{@"name":userName}];
   }
   else
   {
       NSLog(@"Error, something went wrong with user creation");
   }
}

-(BOOL)createFirebaseUser:(NSString*)email andPasswordis:(NSString*)password
{
   goodFirebaseCall = false;
   Firebase* myRef = [[Firebase alloc] initWithUrl:@"https://xxxx.firebaseio.com/"];
   FirebaseSimpleLogin* authClient = [[FirebaseSimpleLogin alloc] initWithRef:myRef];
   [authClient createUserWithEmail:@"email@domain.com" password:@"very secret"
             andCompletionBlock:^(NSError* error, FAUser* user) {
                 if (error != nil) {
                     // There was an error creating the account
                     NSLog(@"%@", error);
                 } else {
                     // We created a new user account
                     goodFirebaseCall = true;
                     NSLog(@"User Created!");
                 }
             }];
    return goodFirebaseCall;
}

Any help on this problem would be greatly appreciated! I've been scratching my head as to why the completion block would never get called.

Thanks, NuttGuy

Answer 1

It looks like you're trying to use createUserWithEmail:password synchronously, but completion blocks are actually executed asynchronously. This allows Firebase to operate in the background and not hang your UI. This means that code you want run after the createUser call should be inside the completion block. You could also use the completion block to call into another method that completes any extra user creation you want.

You can structure your code like this:

- (void)createUser:(NSString *)userName 
         withEmail:(NSString *)email 
       andPassword:(NSString *)password {

    [self createFirebaseUser:userName withEmail:email andPassword:password];
}


- (void)createFirebaseUser:userName 
                 withEmail:(NSString *)email 
               andPassword:(NSString *)password {

    Firebase* myRef = [[Firebase alloc] initWithUrl:@"https://xxxx.firebaseio.com/"];
    FirebaseSimpleLogin* authClient = [[FirebaseSimpleLogin alloc] initWithRef:myRef];
    [authClient createUserWithEmail:email password:password
        andCompletionBlock:^(NSError* error, FAUser* user) {
            if (error != nil) {
                // There was an error creating the account
                 NSLog(@"%@", error);
                [self completeCreateUser:userName 
                        withFirebaseUser:user ifFirebaseSucceeds:NO];
            } else {
                 NSLog(@"User Created! %@", user);
                [self completeCreateUser:userName 
                        withFirebaseUser:user ifFirebaseSucceeds:YES];
            }
    }];
}

- (void)completeCreateUser:(NSString *)userName 
          withFirebaseUser:(FAUser *)user 
        ifFirebaseSucceeds:(BOOL)goodFirebaseCall {
    if (goodFirebaseCall) {
        NSLog(@"User created, but not logged in, now adding the user to Firebase.");
        // Create a reference to a Firebase location
        Firebase* fUsers = [[Firebase alloc] initWithUrl:@"https://xxxx.firebaseio.com/users"];

        Firebase* fNewUser = [fUsers childByAppendingPath:user.uid]; //childByAutoId];
       [fNewUser setValue:@{@"name":userName}];
    } else {
        NSLog(@"Error, something went wrong with user creation");
    }
}

So you see that it's the same if-statement surrounding goodFirebaseCall , but instead of waiting for the BOOL to be returned, you call another method from the completion block and pass it the BOOL you want "returned."

I tried to keep the code the same so that you could see where the segments moved, but you could put all of the code in the third method inside of the completion block if you wanted to. The one thing I did modify was to use user.uid as the path appended to the Firebase users reference since that will always be accessible in your security rules and on FAUser objects, which you'll get from logging in and such.

Also, createUserWithEmail:password will not log in your user. You will have to make another call to loginWithEmail:andPassword:withCompletionBlock: either inside the createUserWithEmail:password completion block, or in the third method.