Authentication Registration Handler class for the LinkedIn

LinkedInRegHandler.cls

global class LinkedInRegHandler implements Auth.RegistrationHandler{
  
  //This method is called when the user log-in using social single sign-on credentials.
  //This method will return the user details, either you can create new user
  //or return the existing user if the match is found
  global User createUser(Id portalId, Auth.UserData data){
    if(data.email.contains('@gmail.com')){
      User u = [Select id,email,isActive from user where email =: data.email and isActive = true Limit 1];
      return u;
    }
    
    return null;
  }
    
  //This method is called, if the user logged in before with the authorization provider and then logs in again.
  global void updateUser(Id userId, Id portalId, Auth.UserData data){
    User u = new User(id=userId);
    u.email = data.email;
    u.lastName = data.lastName;
    u.firstName = data.firstName;
    update(u);
  }
}