How to add WordPress password reset link in HTML email?

Question

I'm trying to replace the WP core password reset email with an Html email. Overall it works great, the emails are well formatted and sent correctly. However, implementing a dynamic reset of the link doesn't work (as does the username, but that's not even the most important thing)

I used the following code in my template's functions.php:

add_filter( 'wp_mail_content_type','prefix_set_content_type' );
function prefix_set_content_type() {
        return "text/html";
}

add_filter( 'retrieve_password_message', 'replace_retrieve_password_message', 10, 2 );
function replace_retrieve_password_message( $message, $key, $user_login, $user_data ) {

        $message = '<html...>A lot of html content (basically formatted emails)</html>'

Doing so will result in a fatal error because the function expects 4 parameters but only receives 2 (said in the bug report email). When I omit $user_data and $key, the error disappears, but I still don't know how to implement dynamic linking...

When I try to include this link in Html, it only sends half of the link (probably due to the '""'):

' . network_site_url( "wp-login.php?action=rp&key=$key&login=" . rawurlencode( $user_login ), ' login' ) . '

Does anyone have any ideas on how to resolve this issue? Thanks.

Answer 1

Put 4 at the end of the line instead of 2.

add_filter('retrieve_password_message', 'replace_retrieve_password_message',10,4);

You must tell add_filter() and add_action() how many arguments the hook function requires.