Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
<?php
/**
* Plugin Name: LH Multipart Email
* Plugin URI: https://lhero.org/portfolio/lh-multipart-email/
* Description: Makes all html emails Html and plain text multipart emails
* Version: 1.10
* Author: Peter Shaw
* Author URI: https://shawfactor.com/
* Text Domain: lh_multipart_email
*
* This gist fixes a problem with sending multiple html mails in one go.
* See comments below.
*/
if ( ! class_exists( 'LH_multipart_email_plugin' ) ) {
/**
* Class LH_multipart_email_plugin
*
* @see: http://wordpress.stackexchange.com/a/191974
* @see: http://stackoverflow.com/a/2564472
*/
class LH_multipart_email_plugin {
public function phpmailer_init( $phpmailer ) {
if ( ( $phpmailer->ContentType == 'text/html' ) && empty( $phpmailer->AltBody ) ) {
if ( ! class_exists( 'Html2Text\Html2Text' ) && ! class_exists( 'Html2Text\Html2TextException' ) ) {
require_once( "includes/Html2Text.php" );
require_once( "includes/Html2TextException.php" );
}
$phpmailer->AltBody = Html2Text\Html2Text::convert( $phpmailer->Body );
}
}
/**
* When multiple mails are sent in a single GET/POST,
* WordPress will reuse the global $phpmailer object.
* Before usage it'll clear any properties it fills itself, but
* since we're adding an AltBody WordPress has no knowledge of,
* it's never cleared when the $phpmailer object is reused.
*
* This results in any 2nd or later mails sent right after the first
* to keep the AltBody that was set on the first mail, effectively
* reusing it.
*
* To prevent this, we're making use of the 'wp_mail' filter, which
* is applied by WordPress early on; well before WP checks if it needs
* to initialize the $phpmailer object.
*
* Using this filter we don't touch the $atts being passed,
* but if the $phpmailer global is a valid PHPMailer object at this
* point in time, it means WordPress is trying to send more
* than one mail or another plugin has already initialized it.
*
* If it's already initialized and an AltBody exists, we need to
* clear it or destroy the $phpmailer object, forcing WordPress
* to reinitialize it.
*
* @param array $wp_mail_atts
*
* @return array
*/
public function force_phpmailer_reinit_for_multiple_mails( $wp_mail_atts ) {
global $phpmailer;
if ( $phpmailer instanceof PHPMailer && $phpmailer->alternativeExists() ) {
// AltBody property is set, so WordPress must already have used this
// $phpmailer object just now to send another mail
$this->reinitialize_phpmailer();
}
return $wp_mail_atts;
}
protected function reinitialize_phpmailer() {
global $phpmailer;
// Clear the AltBody property, or, if filter returns true,
// allow the object to be destroyed instead.
if ( apply_filters( 'lh-multipart-email_destroy-phpmailer', false ) ) {
$phpmailer = null; // destroy object
// Support for WP Mail SMTP ( https://wordpress.org/plugins/wp-mail-smtp/ )
if ( defined( 'WPMS_PLUGIN_VER' ) && class_exists( '\WPMailSMTP\MailCatcher' ) ) {
$phpmailer = new \WPMailSMTP\MailCatcher();
}
} else {
$phpmailer->AltBody = '';
}
// In case other code needs access to the $phpmailer object after we're done with it
do_action( 'lh-multipart-email_phpmailer_reinitialized' );
}
public function __construct() {
add_filter( 'wp_mail', array( $this, "force_phpmailer_reinit_for_multiple_mails" ), -1, 1 );
add_action( 'phpmailer_init', array( $this, "phpmailer_init" ), 1000, 1 );
}
}
$lh_multipart_email_instance = new LH_multipart_email_plugin();
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.