I'm trying to create a persistent login mechanism in Wordpress (I can't find a plugin, but if there is one, let me know!).
But I'm struggling to find a hook (add_action or add_filter) that runs when the user is initially authenticated by wordpress when logging in.
Does anyone know of an appropriate way to execute code only once when a user logs into wordpress?
wp_login action is available.
The wp_login action hook is triggered when a user logs in by the wp_signon() function. It is the very last action taken in the function, immediately following the wp_set_auth_cookie() call.
Check this official documentation.
I know it's been a while, but I've since created a plugin to remember users and keep them logged into WordPress (unless they choose to logout).
Just incase anyone else has a similar question.
The plugin is here: https://wordpress.org/plugins/wp-persistent-login/
It does use wp_login at its core, as suggested in the other answer.
