How to authenticate user with firebase sdk - codeigniter

Question

I am using this SDK and following this documentation. Now I am trying to create and authenticate user in firebase db. How can I do that.I am doing the project in Codeigniter and in my controller I did this:
public function register()
{
$firebase = (new Firebase\Factory())->create();
$tokenHandler = $firebase->getTokenHandler();
$uid = 'a-uid';
$claims = ['foo' => 'bar']; // optional
// Returns a Lcobucci\JWT\Token instance
$customToken = $tokenHandler->createCustomToken($uid, $claims);
echo $customToken; // "eyJ0eXAiOiJKV1..."
$idTokenString = 'eyJhbGciOiJSUzI1...';
// Returns a Lcobucci\JWT\Token instance
$idToken = $tokenHandler->verifyIdToken($idTokenString);
$uid = $idToken->getClaim('sub');
echo $uid; // 'a-uid'
}
and I call the function It gave me this error:
Type: Kreait\Firebase\Exception\ServiceAccountDiscoveryFailed
Message: Kreait\Firebase\ServiceAccount\Discovery\FromEnvironmentVariable: The environment variable "FIREBASE_CREDENTIALS" is not set. Kreait\Firebase\ServiceAccount\Discovery\FromEnvironmentVariable: The environment variable "GOOGLE_APPLICATION_CREDENTIALS" is not set. Kreait\Firebase\ServiceAccount\Discovery\FromGoogleWellKnownFile: The well known file is not readable or invalid
Filename: E:\xampp\htdocs\firebasedb\vendor\kreait\firebase-
php\src\Firebase\ServiceAccount\Discoverer.php
Line Number: 48
Can anyone help me with this issue? Any kind of help are appreciated. Thanks.
EDIT
Okay I solve this problem with default .json file path like this:
$serviceAccount = ServiceAccount::fromJsonFile(JSON_FILE_PATH.'google-service-account.json');
$firebase = (new Factory)
->withServiceAccount($serviceAccount)
->create();
Now can I register a new user from web-app? Can anyone Help please. I have been stopped in this problem since long. Helps are highly appreciated.

Answer 1

You Set JSON Key environment variables
FIREBASE_CREDENTIALS GOOGLE_APPLICATION_CREDENTIALS ?
try reading this Firebase Admin SDK for PHP Setup

Answer 2

From the documentation https://firebase-php.readthedocs.io/en/latest/authentication.html#authenticate-with-admin-privileges
There two crucial points to note.
Many use cases for verifying ID tokens on the server can be accomplished by using Security Rules for the Firebase Realtime Database and Cloud Storage. See if those solve your problem before verifying ID tokens yourself.
The ID token verification methods included in the Firebase Admin SDKs are meant to verify ID tokens that come from the client SDKs, not the custom tokens that you create with the Admin SDKs Check out https://firebase.google.com/docs/auth/users/#auth_tokens
About Users:
From https://firebase-php.readthedocs.io/en/latest/user-management.html
You have a sample
$request = \Kreait\Auth\Request\CreateUser::new()
->withUnverifiedEmail('user#example.com')
->withPhoneNumber('[phone]')
->withClearTextPassword('secretPassword')
->withDisplayName('John Doe')
->withPhotoUrl('http://www.example.com/12345678/photo.png');
$createdUser = $auth->createUser($request);
Please Note:
By default, Firebase Authentication will generate a random uid for the new user. If you instead want to specify your own uid for the new user, you can include in the properties passed to the user creation method:
$properties = [
'uid' => 'some-uid',
// other properties
];
$request = \Kreait\Auth\Request\CreateUser::new()
->withUid('some-uid')
// with other properties
;

Answer 3

I had same problem with Laravel in my case, here is the solution:
First save the .json credentials file you got from Firebase project into the root of your Laravel app on the same level as .env file.
The json file looks like you-file-firebase-adminsdk-0000-9845985498a.json
Then open the .env file and create a new environment variable and paste the json credential file name.
FIREBASE_CREDENTIALS=../you-file-firebase-adminsdk-0000-9845985498a.json