WP Admin page to assist with a migration of users to Auth0 authentication and login

auth0-migration.php

/**
 * Auth0 Migration: Admin Page
 *
 * Provide a UI in the WP admin for migrating users to Auth0
 */
public function auth0_admin_page() {

	// requires admin privledges
	if ( current_user_can('manage_options') ) {

		global $wpdb;
		$wpdb->show_errors();
		?>

		<h2>Auth0 Migration</h2>
		<p>This process will reset all user passwords in <code>users</code> table for this WordPress install, sending the username, email and new password to Auth0 for a smooth transition.</p>

		<?php if ( ! empty( $_POST['emergency_accept'] ) && check_admin_referer( 'emergency_reset', 'emergency_reset' ) ) : ?>

		<p>We've begun the process of migrating all WordPress users to Auth0</p>

		<?php
		$results = $wpdb->get_results( 'SELECT ID FROM '.$wpdb->prefix.'users' );
		if ( $results ) { 
			foreach ( $results as $row ) {

				// gather user and site data
				$user_id = $row->ID;
				$user = get_userdata( $user_id );
				$current_site = get_current_site();
				$domain = ucfirst( $current_site->domain );

				// generate new password
				$password = wp_generate_password();

				// send data to Auth0 API
				// 
				// PHP API calls go here, this may be slow though
				// perhaps storing in a new DB table for importing 
				// into Auth0 database would be better?
				$args = array(
					'user' => esc_attr( $user->user_login ),
					'email' => sanitize_email( $user->user_email ),
					'password' => $password,
				);

				// set new password in WP
				wp_set_password( $password, $user_id );

				// format email message
				$message  = '<p>To keep your information safe and secure your <a href="' . wp_login_url() . '">' . $domain . '</a> password has been reset.</p>';
				$message .= '<p>You can now login with:</p>';
				$message .= '<ul>';
				$message .= '<li><strong>Username</strong>: ' . $user->user_login . '</li>';
				$message .= '<li><strong>Password</strong>: ' . $password . '</li>';
				$message .= '</ul>';
				$message .= '<p>We apologize for any inconvenience this causes,</p>';
				$message .= '<p>Thank you</p>';
				$message .= '<p>The ' . get_bloginfo('name') . 'Team</p>';

				// notify user via email
				add_filter( 'wp_mail_content_type', create_function('', 'return "text/html";' ) );
				wp_mail( $user->user_email, __( "$domain Security Update", 'rapidminer' ), $message );

				// output status
				?>
				<p>Password changed for <strong><?php echo $user->user_login; ?></strong></p>
				<?php
			}
		}
		?>

		<h2>All done</h2>

		<?php else: ?>
		
		<p>
			<form action="" method="post">';
			<?php echo wp_nonce_field('emergency_reset','emergency_reset'); ?>
			<input type="hidden" name="emergency_accept" value="yes"/><input type="submit" value="Reset all passwords"/></form>
		</p>

		<?php endif; // end POST emergency_accept
	}
	else {
		wp_die( "You don't have permission to use this password reset" );
	}
}