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<?php

/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */

/**

 * Key gateway class for XML_Feed_Parser package

 *

 * PHP versions 5

 *

 * LICENSE: This source file is subject to version 3.0 of the PHP license

 * that is available through the world-wide-web at the following URI:

 * http://www.php.net/license/3_0.txt.  If you did not receive a copy of

 * the PHP License and are unable to obtain it through the web, please

 * send a note to license@php.net so we can mail you a copy immediately.

 *

 * @category   XML

 * @package    XML_Feed_Parser

 * @author     James Stewart <james@jystewart.net>

 * @copyright  2005 James Stewart <james@jystewart.net>

 * @license    http://www.gnu.org/copyleft/lesser.html  GNU LGPL

 * @version    CVS: $Id: Parser.php,v 1.2 2007-07-25 15:05:34 jp_milcent Exp $

 * @link       http://pear.php.net/package/XML_Feed_Parser/

 */

/**

 * XML_Feed_Parser_Type is an abstract class required by all of our

 * feed types. It makes sense to load it here to keep the other files

 * clean.

 */

require_once 'XML/Feed/Parser/Type.php';

/**

 * We will throw exceptions when errors occur.

 */

require_once 'XML/Feed/Parser/Exception.php';

/**

 * This is the core of the XML_Feed_Parser package. It identifies feed types

 * and abstracts access to them. It is an iterator, allowing for easy access

 * to the entire feed.

 *

 * @author  James Stewart <james@jystewart.net>

 * @version Release: 1.0.2

 * @package XML_Feed_Parser

 */

class XML_Feed_Parser implements Iterator

{

    /**

     * This is where we hold the feed object

     * @var Object

     */

    private $feed;

    /**

     * To allow for extensions, we make a public reference to the feed model

     * @var DOMDocument

     */

    public $model;

    /**

     * A map between entry ID and offset

     * @var array

     */

    protected $idMappings = array();

    /**

     * A storage space for Namespace URIs.

     * @var array

     */

    private $feedNamespaces = array(

        'rss2' => array(

            'http://backend.userland.com/rss',

            'http://backend.userland.com/rss2',

            'http://blogs.law.harvard.edu/tech/rss'));

    /**

     * Detects feed types and instantiate appropriate objects.

     *

     * Our constructor takes care of detecting feed types and instantiating

     * appropriate classes. For now we're going to treat Atom 0.3 as Atom 1.0

     * but raise a warning. I do not intend to introduce full support for

     * Atom 0.3 as it has been deprecated, but others are welcome to.

     *

     * @param    string    $feed    XML serialization of the feed

     * @param    bool    $strict    Whether or not to validate the feed

     * @param    bool    $suppressWarnings Trigger errors for deprecated feed types?

     * @param    bool    $tidy    Whether or not to try and use the tidy library on input

     */

    function __construct($feed, $strict = false, $suppressWarnings = false, $tidy = false)

    {

        $this->model = new DOMDocument;

        if (! $this->model->loadXML($feed)) {

            if (extension_loaded('tidy') && $tidy) {

                $tidy = new tidy;

                $tidy->parseString($feed,

                    array('input-xml' => true, 'output-xml' => true));

                $tidy->cleanRepair();

                if (! $this->model->loadXML((string) $tidy)) {

                    throw new XML_Feed_Parser_Exception('Invalid input: this is not ' .

                        'valid XML');

                }

            } else {

                throw new XML_Feed_Parser_Exception('Invalid input: this is not valid XML');

            }

        }

        /* detect feed type */

        $doc_element = $this->model->documentElement;

        $error = false;

        switch (true) {

            case ($doc_element->namespaceURI == 'http://www.w3.org/2005/Atom'):

                require_once 'XML/Feed/Parser/Atom.php';

                require_once 'XML/Feed/Parser/AtomElement.php';

                $class = 'XML_Feed_Parser_Atom';

                break;

            case ($doc_element->namespaceURI == 'http://purl.org/atom/ns#'):

                require_once 'XML/Feed/Parser/Atom.php';

                require_once 'XML/Feed/Parser/AtomElement.php';

                $class = 'XML_Feed_Parser_Atom';

                $error = 'Atom 0.3 deprecated, using 1.0 parser which won\'t provide ' .

                    'all options';

                break;

            case ($doc_element->namespaceURI == 'http://purl.org/rss/1.0/' ||

                ($doc_element->hasChildNodes() && $doc_element->childNodes->length > 1

                && $doc_element->childNodes->item(1)->namespaceURI ==

                'http://purl.org/rss/1.0/')):

                require_once 'XML/Feed/Parser/RSS1.php';

                require_once 'XML/Feed/Parser/RSS1Element.php';

                $class = 'XML_Feed_Parser_RSS1';

                break;

            case ($doc_element->namespaceURI == 'http://purl.org/rss/1.1/' ||

                ($doc_element->hasChildNodes() && $doc_element->childNodes->length > 1

                && $doc_element->childNodes->item(1)->namespaceURI ==

                'http://purl.org/rss/1.1/')):

                require_once 'XML/Feed/Parser/RSS11.php';

                require_once 'XML/Feed/Parser/RSS11Element.php';

                $class = 'XML_Feed_Parser_RSS11';

                break;

            case (($doc_element->hasChildNodes() && $doc_element->childNodes->length > 1

                && $doc_element->childNodes->item(1)->namespaceURI ==

                'http://my.netscape.com/rdf/simple/0.9/') ||

                $doc_element->namespaceURI == 'http://my.netscape.com/rdf/simple/0.9/'):

                require_once 'XML/Feed/Parser/RSS09.php';

                require_once 'XML/Feed/Parser/RSS09Element.php';

                $class = 'XML_Feed_Parser_RSS09';

                break;

            case ($doc_element->tagName == 'rss' and

                $doc_element->hasAttribute('version') &&

                $doc_element->getAttribute('version') == 0.91):

                $error = 'RSS 0.91 has been superceded by RSS2.0. Using RSS2.0 parser.';

                require_once 'XML/Feed/Parser/RSS2.php';

                require_once 'XML/Feed/Parser/RSS2Element.php';

                $class = 'XML_Feed_Parser_RSS2';

                break;

            case ($doc_element->tagName == 'rss' and

                $doc_element->hasAttribute('version') &&

                $doc_element->getAttribute('version') == 0.92):

                $error = 'RSS 0.92 has been superceded by RSS2.0. Using RSS2.0 parser.';

                require_once 'XML/Feed/Parser/RSS2.php';

                require_once 'XML/Feed/Parser/RSS2Element.php';

                $class = 'XML_Feed_Parser_RSS2';

                break;

            case (in_array($doc_element->namespaceURI, $this->feedNamespaces['rss2'])

                || $doc_element->tagName == 'rss'):

                if (! $doc_element->hasAttribute('version') ||

                    $doc_element->getAttribute('version') != 2) {

                    $error = 'RSS version not specified. Parsing as RSS2.0';

                }

                require_once 'XML/Feed/Parser/RSS2.php';

                require_once 'XML/Feed/Parser/RSS2Element.php';

                $class = 'XML_Feed_Parser_RSS2';

                break;

            default:

                throw new XML_Feed_Parser_Exception('Feed type unknown');

                break;

        }

        if (! $suppressWarnings && ! empty($error)) {

            trigger_error($error, E_USER_WARNING);

        }

        /* Instantiate feed object */

        $this->feed = new $class($this->model, $strict);

    }

    /**

     * Proxy to allow feed element names to be used as method names

     *

     * For top-level feed elements we will provide access using methods or

     * attributes. This function simply passes on a request to the appropriate

     * feed type object.

     *

     * @param   string  $call - the method being called

     * @param   array   $attributes

     */

    function __call($call, $attributes)

    {

        $attributes = array_pad($attributes, 5, false);

        list($a, $b, $c, $d, $e) = $attributes;

        return $this->feed->$call($a, $b, $c, $d, $e);

    }

    /**

     * Proxy to allow feed element names to be used as attribute names

     *

     * To allow variable-like access to feed-level data we use this

     * method. It simply passes along to __call() which in turn passes

     * along to the relevant object.

     *

     * @param   string  $val - the name of the variable required

     */

    function __get($val)

    {

        return $this->feed->$val;

    }

    /**

     * Provides iteration functionality.

     *

     * Of course we must be able to iterate... This function simply increases

     * our internal counter.

     */

    function next()

    {

        if (isset($this->current_item) &&

            $this->current_item <= $this->feed->numberEntries - 1) {

            ++$this->current_item;

        } else if (! isset($this->current_item)) {

            $this->current_item = 0;

        } else {

            return false;

        }

    }

    /**

     * Return XML_Feed_Type object for current element

     *

     * @return    XML_Feed_Parser_Type Object

     */

    function current()

    {

        return $this->getEntryByOffset($this->current_item);

    }

    /**

     * For iteration -- returns the key for the current stage in the array.

     *

     * @return    int

     */

    function key()

    {

        return $this->current_item;

    }

    /**

     * For iteration -- tells whether we have reached the

     * end.

     *

     * @return    bool

     */

    function valid()

    {

        return $this->current_item < $this->feed->numberEntries;

    }

    /**

     * For iteration -- resets the internal counter to the beginning.

     */

    function rewind()

    {

        $this->current_item = 0;

    }

    /**

     * Provides access to entries by ID if one is specified in the source feed.

     *

     * As well as allowing the items to be iterated over we want to allow

     * users to be able to access a specific entry. This is one of two ways of

     * doing that, the other being by offset. This method can be quite slow

     * if dealing with a large feed that hasn't yet been processed as it

     * instantiates objects for every entry until it finds the one needed.

     *

     * @param    string    $id  Valid ID for the given feed format

     * @return    XML_Feed_Parser_Type|false

     */

    function getEntryById($id)

    {

        if (isset($this->idMappings[$id])) {

            return $this->getEntryByOffset($this->idMappings[$id]);

        }

        /*

         * Since we have not yet encountered that ID, let's go through all the

         * remaining entries in order till we find it.

         * This is a fairly slow implementation, but it should work.

         */

        return $this->feed->getEntryById($id);

    }

    /**

     * Retrieve entry by numeric offset, starting from zero.

     *

     * As well as allowing the items to be iterated over we want to allow

     * users to be able to access a specific entry. This is one of two ways of

     * doing that, the other being by ID.

     *

     * @param    int    $offset The position of the entry within the feed, starting from 0

     * @return    XML_Feed_Parser_Type|false

     */

    function getEntryByOffset($offset)

    {

        if ($offset < $this->feed->numberEntries) {

            if (isset($this->feed->entries[$offset])) {

                return $this->feed->entries[$offset];

            } else {

                try {

                    $this->feed->getEntryByOffset($offset);

                } catch (Exception $e) {

                    return false;

                }

                $id = $this->feed->entries[$offset]->getID();

                $this->idMappings[$id] = $offset;

                return $this->feed->entries[$offset];

            }

        } else {

            return false;

        }

    }

    /**

     * Retrieve version details from feed type class.

     *

     * @return void

     * @author James Stewart

     */

    function version()

    {

        return $this->feed->version;

    }

    /**

     * Returns a string representation of the feed.

     *

     * @return String

     **/

    function __toString()

    {

        return $this->feed->__toString();

    }

}

?>