I try to include the Dilbert Daily Cartoon on a DokuWiki page. Very simple, let's take SimplePie (included with DokuWiki), the URL and on we go.

Very funny. On the demo page of SimplePie everything looks good. But at home? Nothing, “no feed found”. So, let's download the actual version (which includes this demo page), install it locally and – “no feed found”. After some searching on SimplePie's web site I found out that Feedburner does not like SimplePie, so that I have to fake the user agent string…

OK, let's go on. After some hints from Andi Gohr via the mailing list I managed to get it running with the following code:

<?php
/**
 * dilbert plugin: shows the daily cartoon from dilbert.com
 **/
/**
 * @license    GPL 2 (http://www.gnu.org/licenses/gpl.html)
 * @author     Werner Flamme \<w.flamme@web.de>
 * @date       2009-02-02
 */
 
if(!defined('DOKU_INC'))
    die();
if(!defined('DOKU_PLUGIN'))
    define('DOKU_PLUGIN', DOKU_INC . 'lib/plugins/');
require_once(DOKU_PLUGIN . 'syntax.php');
 
/**
 * All DokuWiki plugins to extend the parser/rendering mechanism
 * need to inherit from this class
 **/
class syntax_plugin_dilbert extends DokuWiki_Syntax_Plugin {
 
    /**
     * return some info
     * @return array (hash) with some info about the plugin
     **/
    function getInfo()
    {
        return array(
            'author' => 'Werner Flamme',
            'email'  => 'w.flamme@web.de',
            'date'   => '2009-02-02',
            'name'   => 'Dilbert Daily Cartoon Plugin',
            'desc'   => 'Shows the daily cartoon from dilbert.com ' .
                        'as shown on http://feedproxy.google.com/~r/DilbertDailyStrip/<...>',
            'url'    => 'http://www.wernerflamme.name/doku.php?id=comp:dilbert'
        );
    } // function getInfo
 
    /**
     * What kind of syntax are we?
     * @return string containing the syntax type
     **/
    function getType()
    {
        return 'substition';
    } // function getType
 
    /**
     * What kind of plugin are we?
     * @return string containing the kind of the plugin
     **/
    function getPType()
    {
        return 'block';
    } // function getPType
 
    /**
     * Where to sort in?
     * @return integer number giving the sort sequence number
     **/
    function getSort()
    {
        return 200;
    } // function getSort
 
    /**
     * Connect pattern to lexer
     **/
    function connectTo($mode)
    {
        $this->Lexer->addSpecialPattern('{~dilbert~}', $mode, 'plugin_dilbert');
    } // function connectTo
 
    /**
     * Handle the match
     **/
    function handle($match, $state, $pos) 
    {
        return array();
    } // function handle
 
    /**
     * Create output
     * @param $mode       current mode of DokuWiki 
     *                    (see http://wiki.splitbrain.org/plugin:tutorial)
     * @param $renderer   DokuWiki's rendering object
     * @param $data       (not looked at)
     * @return true, if rendering happens, false in all other cases
     **/
    function render($mode, &$renderer, $data)
    {
        if ($mode == 'xhtml') {
            // we need the SimplePie library
            require_once(DOKU_INC . 'inc/FeedParser.php');
            // where to look for the feed:
            //$url = 'http://feeds.feedburner.com/DilbertDailyStrip?format=xml';
            $url = 'http://feedproxy.google.com/DilbertDailyStrip';
            // create SimplePie feed parsing object
            $feed = new FeedParser();
            // next line is mandatory, since feedburner dislikes simplepie
            $feed->set_useragent('Mozilla/4.5 (as DokuWiki plugin)');
            // point feed to URL
            $feed->set_feed_url($url);
            // get data
            $feed->init();
            // ...and mangle^Wmanage it :-)
            $feed->handle_content_type();
            // we only want the cartoon that was published during last 24 hours
            $yesterday = time() - (24 * 60 * 60);
            // loop at the items in the feed
            foreach ($feed->get_items() as $item) {
                // if the item has been published during the last 24 hours...
                if ($item->get_date('U') > $yesterday) {
                    $feedDescription = hsc($item->get_description());
                    $image           = $this->_returnImage($feedDescription);
                    $imageurl        = $this->_scrapeImage($image);
                    $src             = $imageurl;
                    $title           = 'Dilbert Daily Cartoon';
                    $align           = null;
                    $width           = null;
                    $height          = null;
                    $cache           = false;
                    $renderer->externalmedia($src, $title, $align, $width, $height, $cache);
                } // if ($item->get_date('U') > $yesterday)
            } // foreach ($feed->get_items() as $item)
            return true;
        } // if ($mode == 'xhtml')
        return false;
    } // function render
 
    /**
     * taken from esteban on http://simplepie.org/support/viewtopic.php?id=643
     * Last edited by esteban (23 April 2007 03:06:30)
     *
     * Get an image
     * @return (string) content of image tag in the feed
     **/
    function _returnImage($text)
    {
        $text = html_entity_decode($text, ENT_QUOTES, 'UTF-8');
        $pattern = "/<img[^>]+\>/i";
        preg_match($pattern, $text, $matches);
        $text = $matches[0];
        return urldecode($text);
    } // function _returnImage
 
    /**
     * taken from esteban on http://simplepie.org/support/viewtopic.php?id=643
     * Last edited by esteban (23 April 2007 03:06:30)
     *
     * Filter out image url only
     * @return (string) URL of the picture
    **/
    function _scrapeImage($text) 
    {
        $pattern = '/src=[\'"]?([^\'" >]+)[\'" >]/';
        preg_match($pattern, $text, $link);
        $link = $link[1];
        return hsc($link);
    } // function _scrapeImage
 
} // class syntax_plugin_dilbert
 
//Setup VIM: ex: et ts=4 enc=utf-8 :

The function hsc() is a wrapper around htmlspecialchars() defined in inc/common.php.