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         $manager->addDependency(__FILE__);
  24
  25         // grab the document's links to RSS feeds
  26         // we require that the link have a href, a title and a type
  27         // as well as an rss:for attribute specifying where to grab data
  28         $links = $this->query('//html:link[@rss:for]');
  29
  30         foreach ($links as $link) {
  31             $this->generateRSS($dom, $link, $page);
  32         }
  33
  34     }
  35
  36     /**
  37      * Generates the RSS feed for a specific link in a document
  38      * @param $link <link> DOMElement we're generating feed for
  39      * @param $page Page we're generating for
  40      */
  41     protected function generateRSS($dom, $link, $page) {
  42
  43         // retrieve web-path of the page
  44         $path = $page->getWebPath();
  45         $xc = XHTMLCompiler::getInstance();
  46
  47         // generate RSS template
  48         $rss = new XHTMLCompiler_RSSFeed(
  49             $link->getAttribute('title'),
  50             $path,
  51             $this->confiscateAttr($link, $this->ns, 'description'),
  52             $lang = $dom->documentElement->getAttribute('xml:lang')
  53         );
  54
  55         // retrieve data source
  56         $id = $this->confiscateAttr($link, $this->ns, 'for');
  57         $data_source = $dom->getElementById($id);
  58
  59         // parse data source, add news items
  60         foreach ($data_source->childNodes as $src_item) {
  61             if (! $src_item instanceof DOMElement) continue;
  62             if ($src_item->getAttribute('class') !== 'item') continue;
  63
  64             $title = $date = $body = '';
  65             foreach ($src_item->childNodes as $element) {
  66                 if (! $element instanceof DOMElement) continue;
  67                 $var = $element->getAttribute('class');
  68                 if ($var == 'date') {
  69                     if (($node = $element->childNodes->item(0)) instanceof DOMElement) {
  70                         // If we are using human readable dates but
  71                         // non-parseable machine dates, an abbr
  72                         // element should be inside the element with class="date"
  73                         // with a class atNNN where NNN is the Unix timestamp
  74                         // of publishing.
  75                         $datetime = new DateTime('@' . substr($node->getAttribute('class'), 2));
  76                         $date = $datetime->format('r');
  77                     } else {
  78                         $date = $element->textContent;
  79                     }
  80                 } elseif ($var == 'permalink') {
  81                     $permalink = $element->childNodes->item(0)->getAttribute('href');
  82                 } elseif ($var == 'title' || $var == 'body') {
  83                     $$var = $element->textContent;
  84                 }
  85             }
  86
  87             if (isset($permalink)) {
  88                 // assume that the permalink is an absolute path
  89                 if ($permalink[0] !== '/') {
  90                     trigger_error("Permalink for '$title' is not absolute");
  91                     continue;
  92                 }
  93                 $article_link = 'http://' . $xc->getConf('web_domain') . $permalink;
  94             } else {
  95                 // determine the article link, based off anchors
  96                 $item_id = $src_item->getAttribute('id');
  97                 if (!$item_id) {
  98                     trigger_error("News item '$title' has no ID");
  99                     continue;
 100                 }
 101                 $article_link = $path . '#' . $item_id;
 102             }
 103             $rss->addItem($article_link, $title, $date, $body);
 104
 105         }
 106
 107         // save the feed
 108         $rss->save(
 109             $page->normalizePath(
 110                 $link->getAttribute('href')
 111             )
 112         );
 113
 114     }
 115
 116 }