How to validate fields server side during user creation with Firebase Auth? - ios

I'm trying to use Firebase Auth to create a new user, but I want to validate some fields (pattern matching) using Firestore Security Rules before creating a new account. How can I do that?
In the completion handler for the createUser(withEmail: , password:) function, I am performing some writes to Firestore on successful account creation.
I am facing a problem where sometimes the writes to Firestore may not be successful due to Firestore Secuity Rules (Pattern matching). In this case the write fails but the new user account is still created (since writes are being attempted in completion handler).
// Create User Method - Firebase Auth & Swift
Auth.auth().createUser(withEmail: self.emailTextField.text!, password: self.passwordTextField.text!) { (result, error) in
if error != nil {
print(error?.localizedDescription)
} else {
let userName = [
userName:self.userNameTextField.text!
]
// Writing field Data to Firestore
Firestore.firestore().collection("users").document(self.userNameTextField.text!).setData(userName) {(err) in
if err != nil {
// Rather than throwing a fatalError, how can I ensure new account creation is cancelled so that feedback can be given on the issue with entered field data?
fatalError()
}
I want to ensure a user account is not created in case writes to Firestore are unsuccessful due to a conflict with Firestore Security Rules.

Firebase Authentication doesn't have any security rules. There's currently no way to check if incoming account properties are valid before a user gets created. Security rules only apply to data read and written directly to Cloud Firestore (or Realtime Database, or Cloud Storage) from a mobile or web client.
The only thing you could do is use a Cloud Functions auth trigger to check the account properties after it was created, then delete or deactivate the account if something is wrong.

Related

Security rules of realtime database doesn't work

I have a firebase realtime database as below:
The key for each user is the uid of the authenticated user.
Following the security rules tutorial, I created a simple security rule for authenticated users who have the correct User UID to access the users information.
Part of the Javascript code to access the realtime database is:
fireusers = firebase.database().ref('/users');
this.fireusers.orderByChild('identifier').equalTo(this.email).once("value").then((snapshot) => {
var temp = snapshot.val();
for (var tempkey in temp) {
this.globalvar.userName = temp[tempkey].name
this.globalvar.userCompany = temp[tempkey].company
}
})
But the access is denied, and the error log is:
ERROR Error: Uncaught (in promise): Error: permission_denied at /users: Client doesn't have permission to access the desired data.
Error: permission_denied at /users: Client doesn't have permission to access the desired data.
Can you please help for solving this problem?
Your code (that you didn't share) is trying to read the /users node. Your rules don't grant anyone access to that node, so the read gets rejected.
It is important to realize that Firebase security rules don't filter data, but instead merely check whether the code is trying to access any more data than it is allowed. And in your case it does, so it gets rejected.
To read the data, try to only read the path for the current user's UID: /users/$uid.
Also see: Restricting child/field access with security rules

AWS Cognito check and get users

I'm building an iOS App that is using Amazon MobileHub. Currently it's associated with Cognito and the sign up and sign in flow works great.
What I'm trying to achieve is for one user to be able to add another user as a friend so to speak. To make that possible, I need to check if a user with a specific username exists and if it does, get some attributes such as the name of that target user.
I've tried to use the get user > get details function but it gives me an error Authentication delegate not set.
Here's the code I used:
var pool: AWSCognitoIdentityUserPool?
let user = pool?.getUser(usernameField.text!)
self.pool = AWSCognitoIdentityUserPool.init(forKey: AWSCognitoUserPoolsSignInProviderKey)
user?.getDetails().continueWith { (task: AWSTask<AWSCognitoIdentityUserGetDetailsResponse>) -> Any? in
if let error = task.error as NSError? {
print("ERROR: " + error.localizedDescription)
return ""
}
print(task.result)
return ""
}
An approach I thought of was to store the username and the attributes I want to access to DynamoDB and then access it there but that will just create double unnecessary entries.
The issue you'll run into is that user attributes aren't publicly visible. Only the user who has signed in can call GetUser. If it's a back end process, you could do this via the AdminGetUser operation, but this looks client side so I wouldn't recommend that. The only real way around this would be to do what you suggested at the bottom of your post, ultimately.

iOS - AWS Cognito - Check if user already exists

I want to allow a user to enter their email address/password in a field. Upon continuing, I want to run a check to see if that user already exists. If they do, log them in and continue with app, if they do not, move to account creation flow where they will be instructed to add name, phone number, etc.
I cannot for the life of me find documentation on how to log a user in using AWS Cognito. I should be able to pass email/pass in a call and get a response back that says User Exists/User does not exist or whatever! Am I missing something here?
Any help would be greatly appreciated. I've scoured the documentation..this is my last resort.
In the current SDK, calling getUser on your AWSCognitoIdentityUserPool just constructs the in-memory user object. To make the call over the network, you need to call the getSession method on the constructed user. Here's a Swift 3 method I wrote to check whether an email is available:
/// Check whether an email address is available.
///
/// - Parameters:
/// - email: Check whether this email is available.
/// - completion: Called on completion with parameter true if email is available, and false otherwise.
func checkEmail(_ email: String, completion: #escaping (Bool) -> Void) {
let proposedUser = CognitoIdentityUserPoolManager.shared.pool.getUser(email)
UIApplication.shared.isNetworkActivityIndicatorVisible = true
proposedUser.getSession(email, password: "deadbeef", validationData: nil).continueWith(executor: AWSExecutor.mainThread(), block: { (awsTask) in
UIApplication.shared.isNetworkActivityIndicatorVisible = false
if let error = awsTask.error as? NSError {
// Error implies login failed. Check reason for failure
let exceptionString = error.userInfo["__type"] as! String
if let exception = AWSConstants.ExceptionString(rawValue: exceptionString) {
switch exception {
case .notAuthorizedException, .resourceConflictException:
// Account with this email does exist.
completion(false)
default:
// Some other exception (e.g., UserNotFoundException). Allow user to proceed.
completion(true)
}
} else {
// Some error we did not recognize. Optimistically allow user to proceed.
completion(true)
}
} else {
// No error implies login worked (edge case where proposed email
// is linked with an account which has password 'deadbeef').
completion(false)
}
return nil
})
}
For reference, my ExceptionString enum looks like this:
public enum ExceptionString: String {
/// Thrown during sign-up when email is already taken.
case aliasExistsException = "AliasExistsException"
/// Thrown when a user is not authorized to access the requested resource.
case notAuthorizedException = "NotAuthorizedException"
/// Thrown when the requested resource (for example, a dataset or record) does not exist.
case resourceNotFoundException = "ResourceNotFoundException"
/// Thrown when a user tries to use a login which is already linked to another account.
case resourceConflictException = "ResourceConflictException"
/// Thrown for missing or bad input parameter(s).
case invalidParameterException = "InvalidParameterException"
/// Thrown during sign-up when username is taken.
case usernameExistsException = "UsernameExistsException"
/// Thrown when user has not confirmed his email address.
case userNotConfirmedException = "UserNotConfirmedException"
/// Thrown when specified user does not exist.
case userNotFoundException = "UserNotFoundException"
}
Some clarification is in order. Cognito has several parts. The part that does "Authentication" (which is what you are talking about) is called "Cognito User Pools". Not to be confused with Cognito Federated Identity Pools.
With User Pools you can create usernames and password combinations with attributes, and these can be used to authenticate and deliver a persistent, cross device, Cognito Federated identity identityId to a user (across multiple devices).
Once logged in, the Federated Identity Pool is hooked to roles which can get your "Authorized" to use AWS services (like Dynamo DB etc).
It can be tricky to get all these parts working together and AWS has an online site called "Mobile Hub" that will build code for you and download an xcode project. This process configures the Federated Identity Pool and the User Pool correctly, and connects them all up to a set of example code.
Connecting the credentials provider to the user pool to the identity pool is a bit counterintuitive, but the AWSIdentityManager in the aws-mobilehub-helper-ios on github manages all that for you. So I would recommend starting with mobile hub on the console.
Cognito is a somewhat confusing system, here is a link to a brief powerpoint that hits the highlights of how it works (for people that can't understand the AWS docs (like me)).
With that said, "how to check if a user already exists?"
The most reasonable approach is to create the user (via signup), and get a reject if the name is in use, and suggest that your user try a different username. With respect to the email being in use, you will get that reject upon confirmation (signup sends confirmation id's by email and/or via text). This can be overridden to reclaim the email address, or you can do a test beforehand to see if the email is in use by attempting to log in and looking at the failure code.
you can fetch the user as the other answer suggests, however if you have established in user pools an alias for login (like email) you will find this problematic, because this just tells you if someone has the user name, not if someone is already using the email address, and you will get a reject later at confirmation time.
ListUsers is now a nice way to check for existing usernames.
https://docs.aws.amazon.com/cognito-user-identity-pools/latest/APIReference/API_ListUsers.html
You can also look for existing emails, phone numbers, and other default attributes.
Here is a simple .NET example:
Dim userRequest = New ListUsersRequest With {
.UserPoolId = "poolId",
.Filter = "username = bob#email.com"
}
Dim response = amazonCognitoIdentityProviderClient.ListUsers(userRequest)
Debug.WriteLine(response.Users.Count)

Error adding Firebase users Swift

By following the information on this link, I am currently working on trying to create a user using Firebase, as shown in the code below. However, it appears no user is created when the app is run. Any input is greatly appreciated. The Firebase URL was taken from my test database.
let ref = Firebase(url: "https://test-96df2.firebaseio.com")
ref.createUser("bobtony#example.com", password: "correcthorsebatterystaple",
withValueCompletionBlock: { error, result in
if error != nil {
// There was an error creating the account
print("error creating account")
} else {
let uid = result["uid"] as? String
print("Successfully created user account with uid: \(uid)")
}
})
Edit:
The propagated error is:
Error Code: AUTHENTICATION_DISABLED) Projects created at
console.firebase.google.com must use the new Firebase Authentication
SDKs available from firebase.google.com/docs/auth/
However, as shown below, the email/password authentication is enabled in the Firebase console.
You have already authorized the email registration as I can see in your screenshot. So the problem doesnt realies on AUTHENTICATION_DISABLED.
From your error message and the snippet code I can see that you have created a new project but you are trying to use the legacy firebase SDK and so you will have compatibility issues. Also, you are looking into the old firebase documentation.
First of all you will need to make sure you have configured your project as documented in new firebase start guide.
After, you can take a look at the documentation for creating a new user with the new sdk. You can find the 3.x create user call bellow.
FIRAuth.auth()?.createUserWithEmail(email, password: password) { (user, error) in
// ...
}

Restore Access Token in hybridauth

I saved the Access Token (using this method: getAccessToken ()) in my database, but now I would like to restore this value to an object.
How can I do this?
This is explained in hybridauth user manual with below code :
// get the stored hybridauth data from your storage system
$hybridauth_session_data = get_sorted_hybridauth_session( $current_user_id );
Get_sorted_hybridauth_session is your internal function to get the stored data.
It doesnt matter whether you store the data in a table in a field named 'external_token' or something, get it through a normal sql query, and then just feed it to below function :
// then call Hybrid_Auth::restoreSessionData() to get stored data
$hybridauth->restoreSessionData( $hybridauth_session_data );
// call back an instance of Twitter adapter
$twitter = $hybridauth->getAdapter( "Twitter" );
// regrab te user profile
$user_profile = $twitter->getUserProfile();
$hybridauth->restoreSessionData( $hybridauth_session_data ); will restore the serialized session object, and then it will get an adapter for whichever provider it was saved for. Its best that you also save the provider name (Twitter in this case) in the same database table with something like external_provider , and then you can get it through a sql auery and feed it to getAdapter function. That should do what you need to do.
The manual example is below :
http://hybridauth.sourceforge.net/userguide/HybridAuth_Sessions.html
=============
As an added info - what i saw in my tests was, saving session in this way does not prevent hybridauth from logging the user in, even if the user has revoked access from the app in the meantime. Ie, if user is already logged in and authorized, but, went to the app separately and revoked the access (google for example), hybridauth will still log in the user to your system. Im currently trying to find a way to make sure the user is logged to the remote system too.
Late, but I thought this would help:
The following code verifies and removes those providers from HybridAuth that the user is not truly logged into:
$providers = $this->hybridauthlib->getConnectedProviders();
foreach( $providers as $connectedWith ){
$p = $this->hybridauthlib->getAdapter( $connectedWith );
try {
$p->getUserProfile();
} catch (Exception $e) {
$p->logout();
}
}

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