Markdown/MarkdownPlugin.php

<?php

if (!defined('GNUSOCIAL')) {
    exit(1);
}

require __DIR__ . '/lib/MarkdownProfileBlock.php';

class MarkdownPlugin extends Plugin
{
    const VERSION = '0.1.1';
    const NAME_SPACE = 'markdown'; // 'namespace' is a reserved keyword

    function initialize()
    {
        if (!isset($this->parser)) {
            $this->parser = 'default';
        }
    }

    // From /lib/util.php::common_render_text
    // We don't want to call it directly since we don't want to
    // run common_linkify() on the text
    function render_text($text)
    {
        $text = common_remove_unicode_formatting($text);

        $text = preg_replace('/[\x{0}-\x{8}\x{b}-\x{c}\x{e}-\x{19}]/', '', $text);

        // Link #hashtags
        $rendered = preg_replace_callback('/(^|\&quot\;|\'|\(|\[|\{|\s+)#([\pL\pN_\-\.]{1,64})/u',
                                      function ($m) { return "{$m[1]}#".common_tag_link($m[2]); }, $text);

        return $rendered;
    }

    /**
     * Replace paragraph tags with double <br>s
     *
     * Some clients (ex: AndStatus) display extra whitespace when the
     * notice is wrapped or ends with a <p> tag (GS doesn't wrap notices in <p> tags)
     */
    function fix_whitespace($rendered)
    {
        // Remove <p>s
        $rendered = str_replace('<p>', '', $rendered);

        // Replace </p>s with <br><br>
        $rendered = str_replace('</p>', '<br><br>', $rendered);

        // Remove trailing <br><br>
        return preg_replace('/<br><br>$/', '', $rendered);
    }

    /**
     * Replace double <br>s with a line-break
     *
     * The following input:
     *      Foo
     *
     *      * list
     *      * item
     *
     * Has `$notice->rendered` like this:
     *      Foo<br>
     *      <br>
     *      * list<br>
     *      * item
     *
     * Turns into this after `common_strip_html()`:
     *      Foo
     *
     *
     *      * list
     *
     *      * item
     *
     * This method takes the original `$notice->rendered` and makes it like this:
     *      Foo
     *
     *      * list
     *      * item
     */
    function br2nl ($string)
    {
        // Replace double <br>s with just one EOL
        $string = preg_replace('/(\<br(\s*)?\/?\>\n<br(\s*)?\/?\>)/i', PHP_EOL, $string);

        // Remove <br>s
        return preg_replace('/(\<br(\s*)?\/?\>)/i', '', $string);
    }

    function onChrStartRenderNotice(&$raw_content, $profile, &$render)
    {
        $isEnabled = Profile_prefs::getData($profile, MarkdownPlugin::NAME_SPACE, 'enabled', false);

        if (!$isEnabled) {
            return true;
        }

        $rendered = common_render_content($raw_content, $profile);

        $raw_content = $this->markdownify($rendered);
        $render = false;

        return true;
    }

    function markdownify($rendered_str, $notice=null)
    {
        $text = common_strip_html($this->br2nl($rendered_str), true, true);

        if ($this->parser === 'default') {
            $rendered = $this->render_text($text);

            $rendered = common_replace_urls_callback($text, 'common_linkify');

            // handle Markdown links in order not to convert doubly.
            $rendered = preg_replace('/\[([^]]+)\]\((<a [^>]+>)([^<]+)<\/a>\)/u', '\2\1</a>', $rendered);
        } else {
            $rendered = $this->render_text($text);
        }

        // Some types of notices do not have the hasParent() method,
        // but they're not notices we are interested in
        if (method_exists($notice, 'hasParent')) {
            // Link @mentions, !mentions, @#mentions
            $rendered = common_linkify_mentions($rendered, $notice->getProfile(),
                                            $notice->hasParent() ? $notice->getParent() : null);
        }

        // Prevent leading #hashtags from becoming headers by adding a backslash
        // before the "#", telling markdown to leave it alone
        $repl_rendered = preg_replace('/^#<span class="tag">/u', '\\\\\\0', $rendered);

        // Only use the replaced value from above if it returned a success
        if ($rendered !== null) {
            $rendered = $repl_rendered;
        }

        // Convert Markdown to HTML
        // TODO: Abstract the parser so we can call the same method regardless of lib
        switch($this->parser) {
            case 'gfm':
                // Composer
                require __DIR__ . '/vendor/autoload.php';

                $this->parser = new \cebe\markdown\GithubMarkdown();
                $rendered = $this->parser->parse($rendered);
                break;
            default:
                $this->parser = new \Michelf\Markdown();
                $rendered = $this->parser->defaultTransform($rendered);
        }

        return common_purify($this->fix_whitespace($rendered));
    }

    function onStartShowAccountProfileBlock($action, $profile)
    {
        $markdownProfile = new MarkdownProfileBlock($action, $profile);

        $markdownProfile->show();

        return false;
    }

    function onStartNoticeSave($notice)
    {
        // Only run this on local notices
        if ($notice->isLocal()) {
            // Get the profile of the user who posted this notice
            $profile = Profile::getKV('id', $notice->profile_id);

            // Check if they have 'Markdown' enabled in their settings
            if ($profile instanceof Profile) {
                $isEnabled = Profile_prefs::getData($profile, MarkdownPlugin::NAME_SPACE, 'enabled', false);
            } else {
                $isEnabled = false;
            }

            if (!$isEnabled) {
                return true;
            }

            $notice->rendered = $this->markdownify($notice->rendered, $notice);
        }

        return true;
    }

    function onEndShowStyles($action)
    {
        $action->cssLink($this->path('css/markdown.css'));
    }

    function onEndAccountSettingsNav($action) {
        $action->elementStart('li');
        $action->element('a', array('href' => common_local_url('markdownsettings')), 'Markdown');
        $action->elementEnd('li');

        return true;
    }

    function onRouterInitialized($m)
    {
        $m->connect(
            'settings/markdownsettings', array(
                'action' => 'markdownsettings'
            )
        );

        return true;
    }

    function onPluginVersion(array &$versions): bool
    {
        $versions[] = array('name' => 'Markdown',
                            'version' => self::VERSION,
                            'author' => 'chimo',
                            'homepage' => 'https://github.com/chimo/gs-markdown',
                            'description' =>
                            // TRANS: Plugin description.
                            _m('Use markdown syntax'));
        return true;
    }
}