Mailing-Hooks.php

<?php
/**
 * CiviCRM Mailing_Hooks class.
 *
 * @since 0.1
 */

namespace CiviCRM_WP_REST\Civi;

class Mailing_Hooks {

	/**
	 * Mailing Url endpoint.
	 *
	 * @since 0.1
	 * @var string
	 */
	public $url_endpoint;

	/**
	 * Mailing Open endpoint.
	 *
	 * @since 0.1
	 * @var string
	 */
	public $open_endpoint;

	/**
	 * The parsed WordPress REST url.
	 *
	 * @since 1.0
	 * @var array
	 */
	public $parsed_rest_url;

	/**
	 * Constructor.
	 *
	 * @since 0.1
	 */
	public function __construct() {

		$this->url_endpoint = rest_url( 'civicrm/v3/url' );

		$this->open_endpoint = rest_url( 'civicrm/v3/open' );

		$this->parsed_rest_url = parse_url( rest_url() );

	}

	/**
	 * Register hooks.
	 *
	 * @since 0.1
	 */
	public function register_hooks() {

		add_filter( 'civicrm_alterMailParams', [ $this, 'do_mailing_urls' ], 10, 2 );

		add_filter( 'civicrm_alterExternUrl', [ $this, 'alter_mailing_extern_urls' ], 10, 6 );

	}

	/**
	 * Replaces the open, and click
	 * tracking URLs for a mailing (CiviMail)
	 * with thier REST counterparts.
	 *
	 * @uses 'civicrm_alterExternUrl' filter
	 *
	 * @param \GuzzleHttp\Psr7\Uri $url
	 * @param string|null $path
	 * @param string|null $query
	 * @param string|null $fragment
	 * @param bool|null $absolute
	 * @param bool|null $isSSL
	 */
	public function alter_mailing_extern_urls( &$url, $path, $query, $fragment, $absolute, $isSSL ) {

		if ( $path == 'extern/url' ) {
			$url = $url
				->withHost( $this->parsed_rest_url['host'] )
				->withPath( "{$this->parsed_rest_url['path']}civicrm/v3/url" );
		}

		if ( $path == 'extern/open' ) {
			$url = $url
				->withHost( $this->parsed_rest_url['host'] )
				->withPath( "{$this->parsed_rest_url['path']}civicrm/v3/open" );
		}

	}

	/**
	 * Filters the mailing html and replaces calls to 'extern/url.php' and
	 * 'extern/open.php' with their REST counterparts 'civicrm/v3/url' and 'civicrm/v3/open'.
	 *
	 * @uses 'civicrm_alterMailParams'
	 *
	 * @since 0.1
	 * @param array &$params Mail params
	 * @param string $context The Context
	 * @return array $params The filtered Mail params
	 */
	public function do_mailing_urls( &$params, $context ) {

		if ( in_array( $context, [ 'civimail', 'flexmailer' ] ) ) {

			$params['html'] = $this->is_mail_tracking_url_alterable( $params['html'] )
				? $this->replace_html_mailing_tracking_urls( $params['html'] )
				: $params['html'];

			$params['text'] = $this->is_mail_tracking_url_alterable( $params['text'] )
				? $this->replace_text_mailing_tracking_urls( $params['text'] )
				: $params['text'];

		}

		return $params;

	}

	/**
	 * Replace html mailing tracking urls.
	 *
	 * @since 0.1
	 * @param string $contnet The mailing content
	 * @return string $content The mailing content
	 */
	public function replace_html_mailing_tracking_urls( string $content ) {

		$doc = \phpQuery::newDocument( $content );

		foreach ( $doc[ '[href*="civicrm/extern/url.php"], [src*="civicrm/extern/open.php"]' ] as $element ) {

			$href = pq( $element )->attr( 'href' );
			$src = pq( $element )->attr( 'src' );

			// replace extern/url
			if ( strpos( $href, 'civicrm/extern/url.php' ) )	{

				$query_string = strstr( $href, '?' );
				pq( $element )->attr( 'href', $this->url_endpoint . $query_string );

			}

			// replace extern/open
			if ( strpos( $src, 'civicrm/extern/open.php' ) ) {

				$query_string = strstr( $src, '?' );
				pq( $element )->attr( 'src', $this->open_endpoint . $query_string );

			}

			unset( $href, $src, $query_string );

		}

		return $doc->html();

	}

	/**
	 * Replace text mailing tracking urls.
	 *
	 * @since 0.1
	 * @param string $contnet The mailing content
	 * @return string $content The mailing content
	 */
	public function replace_text_mailing_tracking_urls( string $content ) {

		// replace extern url
		$content = preg_replace( '/http.*civicrm\/extern\/url\.php/i', $this->url_endpoint, $content );

		// replace open url
		$content = preg_replace( '/http.*civicrm\/extern\/open\.php/i', $this->open_endpoint, $content );

		return $content;

	}

	/**
	 * Checks whether for a given mail
	 * content (text or html) the tracking URLs
	 * are alterable/need to be altered.
	 *
	 * @since 0.1
	 * @param string $content The mail content (text or  html)
	 * @return bool $is_alterable
	 */
	public function is_mail_tracking_url_alterable( string $content ) {

		return strpos( $content, 'civicrm/extern/url.php' ) || strpos( $content, 'civicrm/extern/open.php' );

	}

}