Ip\Internal\Content\Filter::ipHead PHP Method

    public static function ipHead($head, $info)
    {
        $relativePath = ipRequest()->getRelativePath();
        $canonicalUrl = null;
        //detect if we need to add canonical meta tag because we are on the home page
        if (ipContent()->getCurrentPage() && ipContent()->getCurrentPage()->getId() == ipContent()->getDefaultPageId() && ipRequest()->getRelativePath() != '') {
            //if current page is the default page of current language and relative path is not empty
            $languages = ipContent()->getLanguages();
            $firstLanguage = $languages[0];
            if (ipContent()->getCurrentLanguage()->getId() == $firstLanguage->getId()) {
                //if current language is the first language, set canonical to the base URL.
                $canonicalUrl = ipConfig()->baseUrl();
            } elseif (ipRequest()->getRoutePath() != '') {
                //if current URL is not equal to the language URL, set canonical as language URL
                $canonicalUrl = ipContent()->getcurrentLanguage()->getLink();
            }
        }
        //detect if we need to add canonical tag because of missing trailing slash
        if (!$canonicalUrl) {
            //if canonicalUrl is not set yet
            if (ipGetOption('Config.trailingSlash', 1) && ipContent()->getCurrentPage()) {
                if (substr($relativePath, -1) != '/') {
                    $canonicalUrl = ipConfig()->baseUrl() . $relativePath . '/';
                }
            } else {
                if (substr($relativePath, -1) == '/') {
                    $canonicalUrl = ipConfig()->baseUrl() . substr($relativePath, 0, -1);
                }
            }
        }
        if ($canonicalUrl) {
            $append = '    <link rel="canonical" href="' . escAttr($canonicalUrl) . '" />' . "\n";
            $head .= $append;
        }
        return $head;
    }