roundcube-easy-unsubscribe/easy_unsubscribe.php

<?php

class easy_unsubscribe extends rcube_plugin {

	public $task = 'mail';
	private $message_headers_done = false;
	private $unsubscribe_img;

	function init() {
        ini_set('display_errors', '1');
        ini_set('display_startup_errors', '1');
        error_reporting(E_ALL);

		$rcmail = rcmail::get_instance();
		$layout = $rcmail->config->get('layout');

		$this->add_hook('message_headers_output', array($this, 'message_headers'));
		$this->add_hook('storage_init', array($this, 'storage_init'));
		
		$this->include_stylesheet('easy_unsubscribe.css');
		$this->include_script('easy_unsubscribe.js');

		$this->add_texts('localization/');

		$rcmail->output->add_label('easy_unsubscribe.confirm');
	}
	
	public function storage_init($p) {
        $p['fetch_body'] = true;
		$p['fetch_headers'] = trim($p['fetch_headers'] . ' ' . strtoupper('List-Unsubscribe'));
		return $p;

	}

    public function decodeMimeHeader($header)  {
        $elements = imap_mime_header_decode($header);

        return array_reduce($elements, function ($carry, $element) {
            return $carry . $element->text;
        }, '');
    }

    public function extractUnsubscribeUrls($content) {
        $pattern = '/https?:\/\/[^\s"\'<>]+\/[^\s"\'<>]*unsubscribe[^\s"\'<>]*/i';
        preg_match_all($pattern, $content, $matches);
        return $matches[0];
    }


    public function message_headers($p) {
        if($this->message_headers_done === false) {

			$this->message_headers_done = true;
			if(!isset($p['headers']->others['list-unsubscribe'])) return $p;

            $urls = [];

            $rcmail = rcmail::get_instance();
            $body = $rcmail->storage->get_body($p['uid']);

            $urls = array_merge($urls, $this->extractUnsubscribeUrls($body));

            $ListUnsubscribe = $this->decodeMimeHeader($p['headers']->others['list-unsubscribe']);
			if (preg_match_all('/<(.+)>/mU', $ListUnsubscribe, $items, PREG_PATTERN_ORDER)) {
				foreach ( $items[1] as $uri ) {
                    $urls[] = $uri;
				}
			}

            $urls = array_unique($urls);

            foreach ($urls as $uri) {
                if (str_contains($uri, 'mailto')) continue;
                if (!str_contains($uri, '?')) continue;

                $this->unsubscribe_img .= '<a class="easy_unsubscribe_link" title="'.$uri.'" data-href="'. htmlentities($uri) .'" target="_blank" onclick="easy_unsubscribe_click(this);"><img src="plugins/easy_unsubscribe/icon.png" alt="' . $this->gettext('unsubscribe') . '" /></a>';
            }

		}

		if(isset($p['output']['subject'])) {
			$p['output']['subject']['value'] = $p['output']['subject']['value'] . $this->unsubscribe_img;
			$p['output']['subject']['html'] = 1;
		}

		return $p;

	}

}