1: <?php
  2: /**
  3:  * Portions Copyright 2005-2007 Zend Technologies USA Inc. (http://www.zend.com)
  4:  * Copyright 2007-2012 Horde LLC (http://www.horde.org/)
  5:  *
  6:  * @category Horde
  7:  * @package  Feed
  8:  */
  9: 
 10: /**
 11:  * Atom feed class
 12:  *
 13:  * The Horde_Feed_Atom class is a concrete subclass of the general
 14:  * Horde_Feed_Base class, tailored for representing an Atom feed. It shares all
 15:  * of the same methods with its parent. The distinction is made in the format of
 16:  * data that Horde_Feed_Atom expects, and as a further pointer for users as to
 17:  * what kind of feed object they have been passed.
 18:  *
 19:  * @category Horde
 20:  * @package  Feed
 21:  */
 22: class Horde_Feed_Atom extends Horde_Feed_Base
 23: {
 24:     /**
 25:      * The classname for individual feed elements.
 26:      *
 27:      * @var string
 28:      */
 29:     protected $_listItemClassName = 'Horde_Feed_Entry_Atom';
 30: 
 31:     /**
 32:      * The default namespace for Atom feeds.
 33:      *
 34:      * @var string
 35:      */
 36:     protected $_defaultNamespace = 'atom';
 37: 
 38:     /**
 39:      * The XML string for an "empty" Atom feed.
 40:      *
 41:      * @var string
 42:      */
 43:     protected $_emptyXml = '<?xml version="1.0" encoding="utf-8"?><feed xmlns="http://www.w3.org/2005/Atom"></feed>';
 44: 
 45:     /**
 46:      * Cache the individual feed elements so they don't need to be
 47:      * searched for on every operation.
 48:      * @return array
 49:      */
 50:     protected function _buildListItemCache()
 51:     {
 52:         $entries = array();
 53:         foreach ($this->_element->childNodes as $child) {
 54:             if ($child->localName == 'entry') {
 55:                 $entries[] = $child;
 56:             }
 57:         }
 58: 
 59:         return $entries;
 60:     }
 61: 
 62:     /**
 63:      * Easy access to <link> tags keyed by "rel" attributes.
 64:      * @TODO rationalize this with other __get/__call access
 65:      *
 66:      * If $elt->link() is called with no arguments, we will attempt to return
 67:      * the value of the <link> tag(s) like all other method-syntax attribute
 68:      * access. If an argument is passed to link(), however, then we will return
 69:      * the "href" value of the first <link> tag that has a "rel" attribute
 70:      * matching $rel:
 71:      *
 72:      * $elt->link(): returns the value of the link tag.
 73:      * $elt->link('self'): returns the href from the first <link rel="self"> in the entry.
 74:      *
 75:      * @param string $rel The "rel" attribute to look for.
 76:      * @return mixed
 77:      */
 78:     public function link($rel = null)
 79:     {
 80:         if ($rel === null) {
 81:             return parent::__call('link', null);
 82:         }
 83: 
 84:         // Index link tags by their "rel" attribute.
 85:         $links = parent::__get('link');
 86:         if (!is_array($links)) {
 87:             if ($links instanceof Horde_Xml_Element) {
 88:                 $links = array($links);
 89:             } else {
 90:                 return $links;
 91:             }
 92:         }
 93: 
 94:         foreach ($links as $link) {
 95:             if (empty($link['rel'])) {
 96:                 continue;
 97:             }
 98:             if ($rel == $link['rel']) {
 99:                 return $link['href'];
100:             }
101:         }
102: 
103:         return null;
104:     }
105: }
106: