XHTMLCompiler/DOMFilter/RSSGenerator.php

   1 <?php
   2
   3 /**
   4  * Generates an RSS feed from a specially designed HTML container indicated
   5  * by rss:for.
   6  */
   7 class XHTMLCompiler_DOMFilter_RSSGenerator extends XHTMLCompiler_DOMFilter
   8 {
   9
  10     protected $name = 'RSSGenerator';
  11     protected $prefix = 'rss';
  12
  13     // new namespace defines the following attributes:
  14     // for - IDREF to an element where we are to get the RSS info from
  15
  16     public function process(DOMDocument $dom, $page, $manager) {
  17
  18         // attempt to find declarations of the namespace
  19         $nodes = $this->query(
  20             "//attribute::*[namespace-uri() = '".$this->ns."']"
  21         );
  22         if (!$nodes->length) return;
  23
  24         // grab the document's links to RSS feeds
  25         // we require that the link have a href, a title and a type
  26         // as well as an rss:for attribute specifying where to grab data
  27         $links = $this->query('//html:link[@rss:for]');
  28
  29         foreach ($links as $link) {
  30             $this->generateRSS($dom, $link, $page);
  31         }
  32
  33     }
  34
  35     /**
  36      * Generates the RSS feed for a specific link in a document
  37      * @param $link <link> DOMElement we're generating feed for
  38      * @param $page Page we're generating for
  39      */
  40     protected function generateRSS($dom, $link, $page) {
  41
  42         // retrieve web-path of the page
  43         $path = $page->getWebPath();
  44
  45         // generate RSS template
  46         $rss = new XHTMLCompiler_RSSFeed(
  47             $link->getAttribute('title'),
  48             $path,
  49             $this->confiscateAttr($link, $this->ns, 'description'),
  50             $lang = $dom->documentElement->getAttribute('xml:lang')
  51         );
  52
  53         // retrieve data source
  54         $id = $this->confiscateAttr($link, $this->ns, 'for');
  55         $data_source = $dom->getElementById($id);
  56
  57         // parse data source, add news items
  58         foreach ($data_source->childNodes as $src_item) {
  59             if (! $src_item instanceof DOMElement) continue;
  60             if ($src_item->getAttribute('class') !== 'item') continue;
  61
  62             $title = $date = $body = '';
  63             foreach ($src_item->childNodes as $element) {
  64                 if (! $element instanceof DOMElement) continue;
  65                 $var = $element->getAttribute('class');
  66                 if ($var == 'title' || $var == 'date' || $var == 'body') {
  67                     $$var = $element->textContent;
  68                 }
  69             }
  70
  71             // determine the article link, based off anchors
  72             $item_id = $src_item->getAttribute('id');
  73             if (!$item_id) {
  74                 trigger_error("News item '$title' has no ID");
  75                 continue;
  76             }
  77             $article_link = $path . '#' . $item_id;
  78
  79             $rss->addItem($article_link, $title, $date, $body);
  80
  81         }
  82
  83         // save the feed
  84         $rss->save(
  85             $page->normalizePath(
  86                 $link->getAttribute('href')
  87             )
  88         );
  89
  90     }
  91
  92 }