Wordpress API to authorize a user - wordpress

Question

Is there some API in Wordpress to 'authorize' a user? Let's say I want to implement something like:
if (1 == 1) {
user_authenticate('userXY');
}
The method user_authenticate would initialize the session and send the necessary cookies to the user.
Thank you!

Answer 1

There are a number of built-in WordPress functions that you may find helpful for what you're trying to do. I'm guessing the most helpful would be the wp_set_auth_cookie function (See: https://developer.wordpress.org/reference/functions/wp_set_auth_cookie/).
You may want to try something like:
wp_clear_auth_cookie();
$user = get_user_by('login', $username);
$user_id = $user->ID;
wp_set_auth_cookie($user_id);
wp_set_current_user($user_id);
or something to that effect.
Here are some other user/cookie/session functions available to you:
In the wp-includes/pluggable.php file
wp_validate_auth_cookie - Validates authentication cookie.
wp_generate_auth_cookie - Generates authentication cookie contents.
wp_parse_auth_cookie - Parses a cookie into its components.
wp_set_auth_cookie - Sets the authentication cookies based on user ID.
wp_clear_auth_cookie - Removes all of the cookies associated with authentication.
wp_get_current_user - Retrieve the current user object.
wp_set_current_user - Changes the current user by ID or name.
In the wp-includes/user.php file
wp_get_session_token - Retrieve the current session token from the logged_in cookie.
wp_get_all_sessions - Retrieve a list of sessions for the current user.
wp_destroy_current_session - Remove the current session token from the database.
wp_destroy_other_sessions - Remove all but the current session token for the current user for the database.
wp_destroy_all_sessions - Remove all session tokens for the current user from the database.
There is also a great plugin (only one file long) that does this sort of thing called User Switching (See: https://wordpress.org/plugins/user-switching/). You may also find some very helpful code from poking around that file.