Execute a custom function on 'user register' or 'login'

Question

I am new to Drupal. I want to execute my custom function every time when user registers or logins to my site. How can I do this?

Answer 1

You can do this using the following hooks in your module.

1. hook_user_login
2. hook_user_register (In D7 we had user_insert hook.)

Examples:

User Login Hook:

function mymodule_user_login($account){

   //your code here
}

User Register Hook:

function mymodule_user_insert(Drupal\Core\Entity\EntityInterface $entity){

   //your code here

}

Answer 2

You can also use rule module for user login/register.