wp-includes/SimplePie/Source.php

<?php
/**
 * SimplePie
 *
 * A PHP-Based RSS and Atom Feed Framework.
 * Takes the hard work out of managing a complete RSS/Atom solution.
 *
 * Copyright (c) 2004-2016, Ryan Parman, Sam Sneddon, Ryan McCue, and contributors
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are
 * permitted provided that the following conditions are met:
 *
 * 	* Redistributions of source code must retain the above copyright notice, this list of
 * 	  conditions and the following disclaimer.
 *
 * 	* Redistributions in binary form must reproduce the above copyright notice, this list
 * 	  of conditions and the following disclaimer in the documentation and/or other materials
 * 	  provided with the distribution.
 *
 * 	* Neither the name of the SimplePie Team nor the names of its contributors may be used
 * 	  to endorse or promote products derived from this software without specific prior
 * 	  written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS
 * AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * @package SimplePie
 * @copyright 2004-2016 Ryan Parman, Sam Sneddon, Ryan McCue
 * @author Ryan Parman
 * @author Sam Sneddon
 * @author Ryan McCue
 * @link http://simplepie.org/ SimplePie
 * @license http://www.opensource.org/licenses/bsd-license.php BSD License
 */

/**
 * Handles `<atom:source>`
 *
 * Used by {@see SimplePie_Item::get_source()}
 *
 * This class can be overloaded with {@see SimplePie::set_source_class()}
 *
 * @package SimplePie
 * @subpackage API
 */
class SimplePie_Source
{
	var $item;
	var $data = array();
	protected $registry;

	public function __construct($item, $data)
	{
		$this->item = $item;
		$this->data = $data;
	}

	public function set_registry(SimplePie_Registry $registry)
	{
		$this->registry = $registry;
	}

	public function __toString()
	{
		return md5(serialize($this->data));
	}

	public function get_source_tags($namespace, $tag)
	{
		if (isset($this->data['child'][$namespace][$tag]))
		{
			return $this->data['child'][$namespace][$tag];
		}

		return null;
	}

	public function get_base($element = array())
	{
		return $this->item->get_base($element);
	}

	public function sanitize($data, $type, $base = '')
	{
		return $this->item->sanitize($data, $type, $base);
	}

	public function get_item()
	{
		return $this->item;
	}

	public function get_title()
	{
		if ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_ATOM_10, 'title'))
		{
			return $this->sanitize($return[0]['data'], $this->registry->call('Misc', 'atom_10_construct_type', array($return[0]['attribs'])), $this->get_base($return[0]));
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_ATOM_03, 'title'))
		{
			return $this->sanitize($return[0]['data'], $this->registry->call('Misc', 'atom_03_construct_type', array($return[0]['attribs'])), $this->get_base($return[0]));
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_RSS_10, 'title'))
		{
			return $this->sanitize($return[0]['data'], SIMPLEPIE_CONSTRUCT_MAYBE_HTML, $this->get_base($return[0]));
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_RSS_090, 'title'))
		{
			return $this->sanitize($return[0]['data'], SIMPLEPIE_CONSTRUCT_MAYBE_HTML, $this->get_base($return[0]));
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_RSS_20, 'title'))
		{
			return $this->sanitize($return[0]['data'], SIMPLEPIE_CONSTRUCT_MAYBE_HTML, $this->get_base($return[0]));
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_DC_11, 'title'))
		{
			return $this->sanitize($return[0]['data'], SIMPLEPIE_CONSTRUCT_TEXT);
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_DC_10, 'title'))
		{
			return $this->sanitize($return[0]['data'], SIMPLEPIE_CONSTRUCT_TEXT);
		}

		return null;
	}

	public function get_category($key = 0)
	{
		$categories = $this->get_categories();
		if (isset($categories[$key]))
		{
			return $categories[$key];
		}

		return null;
	}

	public function get_categories()
	{
		$categories = array();

		foreach ((array) $this->get_source_tags(SIMPLEPIE_NAMESPACE_ATOM_10, 'category') as $category)
		{
			$term = null;
			$scheme = null;
			$label = null;
			if (isset($category['attribs']['']['term']))
			{
				$term = $this->sanitize($category['attribs']['']['term'], SIMPLEPIE_CONSTRUCT_TEXT);
			}
			if (isset($category['attribs']['']['scheme']))
			{
				$scheme = $this->sanitize($category['attribs']['']['scheme'], SIMPLEPIE_CONSTRUCT_TEXT);
			}
			if (isset($category['attribs']['']['label']))
			{
				$label = $this->sanitize($category['attribs']['']['label'], SIMPLEPIE_CONSTRUCT_TEXT);
			}
			$categories[] = $this->registry->create('Category', array($term, $scheme, $label));
		}
		foreach ((array) $this->get_source_tags(SIMPLEPIE_NAMESPACE_RSS_20, 'category') as $category)
		{
			// This is really the label, but keep this as the term also for BC.
			// Label will also work on retrieving because that falls back to term.
			$term = $this->sanitize($category['data'], SIMPLEPIE_CONSTRUCT_TEXT);
			if (isset($category['attribs']['']['domain']))
			{
				$scheme = $this->sanitize($category['attribs']['']['domain'], SIMPLEPIE_CONSTRUCT_TEXT);
			}
			else
			{
				$scheme = null;
			}
			$categories[] = $this->registry->create('Category', array($term, $scheme, null));
		}
		foreach ((array) $this->get_source_tags(SIMPLEPIE_NAMESPACE_DC_11, 'subject') as $category)
		{
			$categories[] = $this->registry->create('Category', array($this->sanitize($category['data'], SIMPLEPIE_CONSTRUCT_TEXT), null, null));
		}
		foreach ((array) $this->get_source_tags(SIMPLEPIE_NAMESPACE_DC_10, 'subject') as $category)
		{
			$categories[] = $this->registry->create('Category', array($this->sanitize($category['data'], SIMPLEPIE_CONSTRUCT_TEXT), null, null));
		}

		if (!empty($categories))
		{
			return array_unique($categories);
		}

		return null;
	}

	public function get_author($key = 0)
	{
		$authors = $this->get_authors();
		if (isset($authors[$key]))
		{
			return $authors[$key];
		}

		return null;
	}

	public function get_authors()
	{
		$authors = array();
		foreach ((array) $this->get_source_tags(SIMPLEPIE_NAMESPACE_ATOM_10, 'author') as $author)
		{
			$name = null;
			$uri = null;
			$email = null;
			if (isset($author['child'][SIMPLEPIE_NAMESPACE_ATOM_10]['name'][0]['data']))
			{
				$name = $this->sanitize($author['child'][SIMPLEPIE_NAMESPACE_ATOM_10]['name'][0]['data'], SIMPLEPIE_CONSTRUCT_TEXT);
			}
			if (isset($author['child'][SIMPLEPIE_NAMESPACE_ATOM_10]['uri'][0]['data']))
			{
				$uri = $this->sanitize($author['child'][SIMPLEPIE_NAMESPACE_ATOM_10]['uri'][0]['data'], SIMPLEPIE_CONSTRUCT_IRI, $this->get_base($author['child'][SIMPLEPIE_NAMESPACE_ATOM_10]['uri'][0]));
			}
			if (isset($author['child'][SIMPLEPIE_NAMESPACE_ATOM_10]['email'][0]['data']))
			{
				$email = $this->sanitize($author['child'][SIMPLEPIE_NAMESPACE_ATOM_10]['email'][0]['data'], SIMPLEPIE_CONSTRUCT_TEXT);
			}
			if ($name !== null || $email !== null || $uri !== null)
			{
				$authors[] = $this->registry->create('Author', array($name, $uri, $email));
			}
		}
		if ($author = $this->get_source_tags(SIMPLEPIE_NAMESPACE_ATOM_03, 'author'))
		{
			$name = null;
			$url = null;
			$email = null;
			if (isset($author[0]['child'][SIMPLEPIE_NAMESPACE_ATOM_03]['name'][0]['data']))
			{
				$name = $this->sanitize($author[0]['child'][SIMPLEPIE_NAMESPACE_ATOM_03]['name'][0]['data'], SIMPLEPIE_CONSTRUCT_TEXT);
			}
			if (isset($author[0]['child'][SIMPLEPIE_NAMESPACE_ATOM_03]['url'][0]['data']))
			{
				$url = $this->sanitize($author[0]['child'][SIMPLEPIE_NAMESPACE_ATOM_03]['url'][0]['data'], SIMPLEPIE_CONSTRUCT_IRI, $this->get_base($author[0]['child'][SIMPLEPIE_NAMESPACE_ATOM_03]['url'][0]));
			}
			if (isset($author[0]['child'][SIMPLEPIE_NAMESPACE_ATOM_03]['email'][0]['data']))
			{
				$email = $this->sanitize($author[0]['child'][SIMPLEPIE_NAMESPACE_ATOM_03]['email'][0]['data'], SIMPLEPIE_CONSTRUCT_TEXT);
			}
			if ($name !== null || $email !== null || $url !== null)
			{
				$authors[] = $this->registry->create('Author', array($name, $url, $email));
			}
		}
		foreach ((array) $this->get_source_tags(SIMPLEPIE_NAMESPACE_DC_11, 'creator') as $author)
		{
			$authors[] = $this->registry->create('Author', array($this->sanitize($author['data'], SIMPLEPIE_CONSTRUCT_TEXT), null, null));
		}
		foreach ((array) $this->get_source_tags(SIMPLEPIE_NAMESPACE_DC_10, 'creator') as $author)
		{
			$authors[] = $this->registry->create('Author', array($this->sanitize($author['data'], SIMPLEPIE_CONSTRUCT_TEXT), null, null));
		}
		foreach ((array) $this->get_source_tags(SIMPLEPIE_NAMESPACE_ITUNES, 'author') as $author)
		{
			$authors[] = $this->registry->create('Author', array($this->sanitize($author['data'], SIMPLEPIE_CONSTRUCT_TEXT), null, null));
		}

		if (!empty($authors))
		{
			return array_unique($authors);
		}

		return null;
	}

	public function get_contributor($key = 0)
	{
		$contributors = $this->get_contributors();
		if (isset($contributors[$key]))
		{
			return $contributors[$key];
		}

		return null;
	}

	public function get_contributors()
	{
		$contributors = array();
		foreach ((array) $this->get_source_tags(SIMPLEPIE_NAMESPACE_ATOM_10, 'contributor') as $contributor)
		{
			$name = null;
			$uri = null;
			$email = null;
			if (isset($contributor['child'][SIMPLEPIE_NAMESPACE_ATOM_10]['name'][0]['data']))
			{
				$name = $this->sanitize($contributor['child'][SIMPLEPIE_NAMESPACE_ATOM_10]['name'][0]['data'], SIMPLEPIE_CONSTRUCT_TEXT);
			}
			if (isset($contributor['child'][SIMPLEPIE_NAMESPACE_ATOM_10]['uri'][0]['data']))
			{
				$uri = $this->sanitize($contributor['child'][SIMPLEPIE_NAMESPACE_ATOM_10]['uri'][0]['data'], SIMPLEPIE_CONSTRUCT_IRI, $this->get_base($contributor['child'][SIMPLEPIE_NAMESPACE_ATOM_10]['uri'][0]));
			}
			if (isset($contributor['child'][SIMPLEPIE_NAMESPACE_ATOM_10]['email'][0]['data']))
			{
				$email = $this->sanitize($contributor['child'][SIMPLEPIE_NAMESPACE_ATOM_10]['email'][0]['data'], SIMPLEPIE_CONSTRUCT_TEXT);
			}
			if ($name !== null || $email !== null || $uri !== null)
			{
				$contributors[] = $this->registry->create('Author', array($name, $uri, $email));
			}
		}
		foreach ((array) $this->get_source_tags(SIMPLEPIE_NAMESPACE_ATOM_03, 'contributor') as $contributor)
		{
			$name = null;
			$url = null;
			$email = null;
			if (isset($contributor['child'][SIMPLEPIE_NAMESPACE_ATOM_03]['name'][0]['data']))
			{
				$name = $this->sanitize($contributor['child'][SIMPLEPIE_NAMESPACE_ATOM_03]['name'][0]['data'], SIMPLEPIE_CONSTRUCT_TEXT);
			}
			if (isset($contributor['child'][SIMPLEPIE_NAMESPACE_ATOM_03]['url'][0]['data']))
			{
				$url = $this->sanitize($contributor['child'][SIMPLEPIE_NAMESPACE_ATOM_03]['url'][0]['data'], SIMPLEPIE_CONSTRUCT_IRI, $this->get_base($contributor['child'][SIMPLEPIE_NAMESPACE_ATOM_03]['url'][0]));
			}
			if (isset($contributor['child'][SIMPLEPIE_NAMESPACE_ATOM_03]['email'][0]['data']))
			{
				$email = $this->sanitize($contributor['child'][SIMPLEPIE_NAMESPACE_ATOM_03]['email'][0]['data'], SIMPLEPIE_CONSTRUCT_TEXT);
			}
			if ($name !== null || $email !== null || $url !== null)
			{
				$contributors[] = $this->registry->create('Author', array($name, $url, $email));
			}
		}

		if (!empty($contributors))
		{
			return array_unique($contributors);
		}

		return null;
	}

	public function get_link($key = 0, $rel = 'alternate')
	{
		$links = $this->get_links($rel);
		if (isset($links[$key]))
		{
			return $links[$key];
		}

		return null;
	}

	/**
	 * Added for parity between the parent-level and the item/entry-level.
	 */
	public function get_permalink()
	{
		return $this->get_link(0);
	}

	public function get_links($rel = 'alternate')
	{
		if (!isset($this->data['links']))
		{
			$this->data['links'] = array();
			if ($links = $this->get_source_tags(SIMPLEPIE_NAMESPACE_ATOM_10, 'link'))
			{
				foreach ($links as $link)
				{
					if (isset($link['attribs']['']['href']))
					{
						$link_rel = (isset($link['attribs']['']['rel'])) ? $link['attribs']['']['rel'] : 'alternate';
						$this->data['links'][$link_rel][] = $this->sanitize($link['attribs']['']['href'], SIMPLEPIE_CONSTRUCT_IRI, $this->get_base($link));
					}
				}
			}
			if ($links = $this->get_source_tags(SIMPLEPIE_NAMESPACE_ATOM_03, 'link'))
			{
				foreach ($links as $link)
				{
					if (isset($link['attribs']['']['href']))
					{
						$link_rel = (isset($link['attribs']['']['rel'])) ? $link['attribs']['']['rel'] : 'alternate';
						$this->data['links'][$link_rel][] = $this->sanitize($link['attribs']['']['href'], SIMPLEPIE_CONSTRUCT_IRI, $this->get_base($link));

					}
				}
			}
			if ($links = $this->get_source_tags(SIMPLEPIE_NAMESPACE_RSS_10, 'link'))
			{
				$this->data['links']['alternate'][] = $this->sanitize($links[0]['data'], SIMPLEPIE_CONSTRUCT_IRI, $this->get_base($links[0]));
			}
			if ($links = $this->get_source_tags(SIMPLEPIE_NAMESPACE_RSS_090, 'link'))
			{
				$this->data['links']['alternate'][] = $this->sanitize($links[0]['data'], SIMPLEPIE_CONSTRUCT_IRI, $this->get_base($links[0]));
			}
			if ($links = $this->get_source_tags(SIMPLEPIE_NAMESPACE_RSS_20, 'link'))
			{
				$this->data['links']['alternate'][] = $this->sanitize($links[0]['data'], SIMPLEPIE_CONSTRUCT_IRI, $this->get_base($links[0]));
			}

			$keys = array_keys($this->data['links']);
			foreach ($keys as $key)
			{
				if ($this->registry->call('Misc', 'is_isegment_nz_nc', array($key)))
				{
					if (isset($this->data['links'][SIMPLEPIE_IANA_LINK_RELATIONS_REGISTRY . $key]))
					{
						$this->data['links'][SIMPLEPIE_IANA_LINK_RELATIONS_REGISTRY . $key] = array_merge($this->data['links'][$key], $this->data['links'][SIMPLEPIE_IANA_LINK_RELATIONS_REGISTRY . $key]);
						$this->data['links'][$key] =& $this->data['links'][SIMPLEPIE_IANA_LINK_RELATIONS_REGISTRY . $key];
					}
					else
					{
						$this->data['links'][SIMPLEPIE_IANA_LINK_RELATIONS_REGISTRY . $key] =& $this->data['links'][$key];
					}
				}
				elseif (substr($key, 0, 41) === SIMPLEPIE_IANA_LINK_RELATIONS_REGISTRY)
				{
					$this->data['links'][substr($key, 41)] =& $this->data['links'][$key];
				}
				$this->data['links'][$key] = array_unique($this->data['links'][$key]);
			}
		}

		if (isset($this->data['links'][$rel]))
		{
			return $this->data['links'][$rel];
		}

		return null;
	}

	public function get_description()
	{
		if ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_ATOM_10, 'subtitle'))
		{
			return $this->sanitize($return[0]['data'], $this->registry->call('Misc', 'atom_10_construct_type', array($return[0]['attribs'])), $this->get_base($return[0]));
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_ATOM_03, 'tagline'))
		{
			return $this->sanitize($return[0]['data'], $this->registry->call('Misc', 'atom_03_construct_type', array($return[0]['attribs'])), $this->get_base($return[0]));
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_RSS_10, 'description'))
		{
			return $this->sanitize($return[0]['data'], SIMPLEPIE_CONSTRUCT_MAYBE_HTML, $this->get_base($return[0]));
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_RSS_090, 'description'))
		{
			return $this->sanitize($return[0]['data'], SIMPLEPIE_CONSTRUCT_MAYBE_HTML, $this->get_base($return[0]));
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_RSS_20, 'description'))
		{
			return $this->sanitize($return[0]['data'], SIMPLEPIE_CONSTRUCT_MAYBE_HTML, $this->get_base($return[0]));
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_DC_11, 'description'))
		{
			return $this->sanitize($return[0]['data'], SIMPLEPIE_CONSTRUCT_TEXT);
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_DC_10, 'description'))
		{
			return $this->sanitize($return[0]['data'], SIMPLEPIE_CONSTRUCT_TEXT);
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_ITUNES, 'summary'))
		{
			return $this->sanitize($return[0]['data'], SIMPLEPIE_CONSTRUCT_HTML, $this->get_base($return[0]));
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_ITUNES, 'subtitle'))
		{
			return $this->sanitize($return[0]['data'], SIMPLEPIE_CONSTRUCT_HTML, $this->get_base($return[0]));
		}

		return null;
	}

	public function get_copyright()
	{
		if ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_ATOM_10, 'rights'))
		{
			return $this->sanitize($return[0]['data'], $this->registry->call('Misc', 'atom_10_construct_type', array($return[0]['attribs'])), $this->get_base($return[0]));
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_ATOM_03, 'copyright'))
		{
			return $this->sanitize($return[0]['data'], $this->registry->call('Misc', 'atom_03_construct_type', array($return[0]['attribs'])), $this->get_base($return[0]));
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_RSS_20, 'copyright'))
		{
			return $this->sanitize($return[0]['data'], SIMPLEPIE_CONSTRUCT_TEXT);
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_DC_11, 'rights'))
		{
			return $this->sanitize($return[0]['data'], SIMPLEPIE_CONSTRUCT_TEXT);
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_DC_10, 'rights'))
		{
			return $this->sanitize($return[0]['data'], SIMPLEPIE_CONSTRUCT_TEXT);
		}

		return null;
	}

	public function get_language()
	{
		if ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_RSS_20, 'language'))
		{
			return $this->sanitize($return[0]['data'], SIMPLEPIE_CONSTRUCT_TEXT);
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_DC_11, 'language'))
		{
			return $this->sanitize($return[0]['data'], SIMPLEPIE_CONSTRUCT_TEXT);
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_DC_10, 'language'))
		{
			return $this->sanitize($return[0]['data'], SIMPLEPIE_CONSTRUCT_TEXT);
		}
		elseif (isset($this->data['xml_lang']))
		{
			return $this->sanitize($this->data['xml_lang'], SIMPLEPIE_CONSTRUCT_TEXT);
		}

		return null;
	}

	public function get_latitude()
	{
		if ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_W3C_BASIC_GEO, 'lat'))
		{
			return (float) $return[0]['data'];
		}
		elseif (($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_GEORSS, 'point')) && preg_match('/^((?:-)?[0-9]+(?:\.[0-9]+)) ((?:-)?[0-9]+(?:\.[0-9]+))$/', trim($return[0]['data']), $match))
		{
			return (float) $match[1];
		}

		return null;
	}

	public function get_longitude()
	{
		if ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_W3C_BASIC_GEO, 'long'))
		{
			return (float) $return[0]['data'];
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_W3C_BASIC_GEO, 'lon'))
		{
			return (float) $return[0]['data'];
		}
		elseif (($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_GEORSS, 'point')) && preg_match('/^((?:-)?[0-9]+(?:\.[0-9]+)) ((?:-)?[0-9]+(?:\.[0-9]+))$/', trim($return[0]['data']), $match))
		{
			return (float) $match[2];
		}

		return null;
	}

	public function get_image_url()
	{
		if ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_ITUNES, 'image'))
		{
			return $this->sanitize($return[0]['attribs']['']['href'], SIMPLEPIE_CONSTRUCT_IRI);
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_ATOM_10, 'logo'))
		{
			return $this->sanitize($return[0]['data'], SIMPLEPIE_CONSTRUCT_IRI, $this->get_base($return[0]));
		}
		elseif ($return = $this->get_source_tags(SIMPLEPIE_NAMESPACE_ATOM_10, 'icon'))
		{
			return $this->sanitize($return[0]['data'], SIMPLEPIE_CONSTRUCT_IRI, $this->get_base($return[0]));
		}

		return null;
	}
}