1<?php
2
3use dokuwiki\Extension\ActionPlugin;
4use dokuwiki\Extension\EventHandler;
5
6class action_plugin_googletagmanager extends ActionPlugin
7{
8    public const GTMID = 'GTMID';
9
10    /**
11     * Register its handlers with the DokuWiki's event controller
12     */
13    public function register(EventHandler $controller)
14    {
15        $controller->register_hook('TPL_METAHEADER_OUTPUT', 'BEFORE', $this, 'addHeaders');
16    }
17
18    public function addHeaders(&$event, $param)
19    {
20        $GTMID = $this->getConf(self::GTMID);
21        if (!$GTMID) return;
22
23        $is_AW_tag = substr($GTMID, 0, 3) == 'AW-';
24
25        if ($is_AW_tag) {
26            $script1 = "https://www.googletagmanager.com/gtag/js?id={$GTMID}";
27            $script2 = <<<EOT
28                window.dataLayer = window.dataLayer || []; function gtag(){dataLayer.push(arguments);}
29                gtag('js', new Date()); gtag('config', '{$GTMID}');";
30                EOT;
31
32            $event->data['script'][] = ['src' => $script1];
33            $event->data['script'][] = ['type' => 'text/javascript', '_data' => $script2];
34        } else {
35            $iframe = <<<EOT
36                <iframe src="https://www.googletagmanager.com/ns.html?id={$GTMID}"
37                height="0" width="0" style="display:none;visibility:hidden"></iframe>
38                EOT;
39
40            $script = <<<EOT
41                (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
42                new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
43                j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
44                'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
45                })(window,document,'script','dataLayer','{$GTMID}');
46                EOT;
47
48            $event->data['noscript'][] = ['_data' => $iframe];
49            $event->data['script'][] = ['type' => 'text/javascript', '_data' => $script];
50        }
51    }
52}
53