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<?php

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

/**

 * Atom feed class for XML_Feed_Parser

 *

 * 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 2.1

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

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

*/

/**

 * This is the class that determines how we manage Atom 1.0 feeds

 *

 * How we deal with constructs:

 *  date - return as unix datetime for use with the 'date' function unless specified otherwise

 *  text - return as is. optional parameter will give access to attributes

 *  person - defaults to name, but parameter based access

 *

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

 * @version    Release: 1.0.2

 * @package XML_Feed_Parser

 */

class XML_Feed_Parser_Atom extends XML_Feed_Parser_Type

{

    /**

     * The URI of the RelaxNG schema used to (optionally) validate the feed

     * @var string

     */

    private $relax = 'atom.rnc';

    /**

     * We're likely to use XPath, so let's keep it global

     * @var DOMXPath

     */

    public $xpath;

    /**

     * When performing XPath queries we will use this prefix

     * @var string

     */

    private $xpathPrefix = '//';

    /**

     * The feed type we are parsing

     * @var string

     */

    public $version = 'Atom 1.0';

    /**

     * The class used to represent individual items

     * @var string

     */

    protected $itemClass = 'XML_Feed_Parser_AtomElement';

    /**

     * The element containing entries

     * @var string

     */

    protected $itemElement = 'entry';

    /**

     * Here we map those elements we're not going to handle individually

     * to the constructs they are. The optional second parameter in the array

     * tells the parser whether to 'fall back' (not apt. at the feed level) or

     * fail if the element is missing. If the parameter is not set, the function

     * will simply return false and leave it to the client to decide what to do.

     * @var array

     */

    protected $map = array(

        'author' => array('Person'),

        'contributor' => array('Person'),

        'icon' => array('Text'),

        'logo' => array('Text'),

        'id' => array('Text', 'fail'),

        'rights' => array('Text'),

        'subtitle' => array('Text'),

        'title' => array('Text', 'fail'),

        'updated' => array('Date', 'fail'),

        'link' => array('Link'),

        'generator' => array('Text'),

        'category' => array('Category'));

    /**

     * Here we provide a few mappings for those very special circumstances in

     * which it makes sense to map back to the RSS2 spec. Key is RSS2 version

     * value is an array consisting of the equivalent in atom and any attributes

     * needed to make the mapping.

     * @var array

     */

    protected $compatMap = array(

        'guid' => array('id'),

        'links' => array('link'),

        'tags' => array('category'),

        'contributors' => array('contributor'));

    /**

     * Our constructor does nothing more than its parent.

     *

     * @param    DOMDocument    $xml    A DOM object representing the feed

     * @param    bool (optional) $string    Whether or not to validate this feed

     */

    function __construct(DOMDocument $model, $strict = false)

    {

        $this->model = $model;

        if ($strict) {

            if (! $this->model->relaxNGValidateSource($this->relax)) {

                throw new XML_Feed_Parser_Exception('Failed required validation');

            }

        }

        $this->xpath = new DOMXPath($this->model);

        $this->xpath->registerNamespace('atom', 'http://www.w3.org/2005/Atom');

        $this->numberEntries = $this->count('entry');

    }

    /**

     * Implement retrieval of an entry based on its ID for atom feeds.

     *

     * This function uses XPath to get the entry based on its ID. If DOMXPath::evaluate

     * is available, we also use that to store a reference to the entry in the array

     * used by getEntryByOffset so that method does not have to seek out the entry

     * if it's requested that way.

     *

     * @param    string    $id    any valid Atom ID.

     * @return    XML_Feed_Parser_AtomElement

     */

    function getEntryById($id)

    {

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

            return $this->entries[$this->idMappings[$id]];

        }

        $entries = $this->xpath->query("//atom:entry[atom:id='$id']");

        if ($entries->length > 0) {

            $xmlBase = $entries->item(0)->baseURI;

            $entry = new $this->itemElement($entries->item(0), $this, $xmlBase);

            if (in_array('evaluate', get_class_methods($this->xpath))) {

                $offset = $this->xpath->evaluate("count(preceding-sibling::atom:entry)", $entries->item(0));

                $this->entries[$offset] = $entry;

            }

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

            return $entry;

        }

    }

    /**

     * Retrieves data from a person construct.

     *

     * Get a person construct. We default to the 'name' element but allow

     * access to any of the elements.

     *

     * @param    string    $method    The name of the person construct we want

     * @param    array     $arguments    An array which we hope gives a 'param'

     * @return    string|false

     */

    protected function getPerson($method, $arguments)

    {

        $offset = empty($arguments[0]) ? 0 : $arguments[0];

        $parameter = empty($arguments[1]['param']) ? 'name' : $arguments[1]['param'];

        $section = $this->model->getElementsByTagName($method);

        if ($parameter == 'url') {

            $parameter = 'uri';

        }

        if ($section->length <= $offset) {

            return false;

        }

        $param = $section->item($offset)->getElementsByTagName($parameter);

        if ($param->length == 0) {

            return false;

        }

        return $param->item(0)->nodeValue;

    }

    /**

     * Retrieves an element's content where that content is a text construct.

     *

     * Get a text construct. When calling this method, the two arguments

     * allowed are 'offset' and 'attribute', so $parser->subtitle() would

     * return the content of the element, while $parser->subtitle(false, 'type')

     * would return the value of the type attribute.

     *

     * @todo    Clarify overlap with getContent()

     * @param    string    $method    The name of the text construct we want

     * @param    array     $arguments    An array which we hope gives a 'param'

     * @return    string

     */

    protected function getText($method, $arguments)

    {

        $offset = empty($arguments[0]) ? 0: $arguments[0];

        $attribute = empty($arguments[1]) ? false : $arguments[1];

        $tags = $this->model->getElementsByTagName($method);

        if ($tags->length <= $offset) {

            return false;

        }

        $content = $tags->item($offset);

        if (! $content->hasAttribute('type')) {

            $content->setAttribute('type', 'text');

        }

        $type = $content->getAttribute('type');

        if (! empty($attribute) and

            ! ($method == 'generator' and $attribute == 'name')) {

            if ($content->hasAttribute($attribute)) {

                return $content->getAttribute($attribute);

            } else if ($attribute == 'href' and $content->hasAttribute('uri')) {

                return $content->getAttribute('uri');

            }

            return false;

        }

        return $this->parseTextConstruct($content);

    }

    /**

     * Extract content appropriately from atom text constructs

     *

     * Because of different rules applied to the content element and other text

     * constructs, they are deployed as separate functions, but they share quite

     * a bit of processing. This method performs the core common process, which is

     * to apply the rules for different mime types in order to extract the content.

     *

     * @param   DOMNode $content    the text construct node to be parsed

     * @return String

     * @author James Stewart

     **/

    protected function parseTextConstruct(DOMNode $content)

    {

        if ($content->hasAttribute('type')) {

            $type = $content->getAttribute('type');

        } else {

            $type = 'text';

        }

        if (strpos($type, 'text/') === 0) {

            $type = 'text';

        }

        switch ($type) {

            case 'text':

                return $content->nodeValue;

                break;

            case 'html':

                return str_replace('&lt;', '<', $content->nodeValue);

                break;

            case 'xhtml':

                $container = $content->getElementsByTagName('div');

                if ($container->length == 0) {

                    return false;

                }

                $contents = $container->item(0);

                if ($contents->hasChildNodes()) {

                    /* Iterate through, applying xml:base and store the result */

                    $result = '';

                    foreach ($contents->childNodes as $node) {

                        $result .= $this->traverseNode($node);

                    }

                    return utf8_decode($result);

                }

                break;

            case preg_match('@^[a-zA-Z]+/[a-zA-Z+]*xml@i', $type) > 0:

                return $content;

                break;

            case 'application/octet-stream':

            default:

                return base64_decode(trim($content->nodeValue));

                break;

        }

        return false;

    }

    /**

     * Get a category from the entry.

     *

     * A feed or entry can have any number of categories. A category can have the

     * attributes term, scheme and label.

     *

     * @param    string    $method    The name of the text construct we want

     * @param    array     $arguments    An array which we hope gives a 'param'

     * @return    string

     */

    function getCategory($method, $arguments)

    {

        $offset = empty($arguments[0]) ? 0: $arguments[0];

        $attribute = empty($arguments[1]) ? 'term' : $arguments[1];

        $categories = $this->model->getElementsByTagName('category');

        if ($categories->length <= $offset) {

            $category = $categories->item($offset);

            if ($category->hasAttribute($attribute)) {

                return $category->getAttribute($attribute);

            }

        }

        return false;

    }

    /**

     * This element must be present at least once with rel="feed". This element may be

     * present any number of further times so long as there is no clash. If no 'rel' is

     * present and we're asked for one, we follow the example of the Universal Feed

     * Parser and presume 'alternate'.

     *

     * @param    int    $offset    the position of the link within the container

     * @param    string    $attribute    the attribute name required

     * @param    array     an array of attributes to search by

     * @return    string    the value of the attribute

     */

    function getLink($offset = 0, $attribute = 'href', $params = false)

    {

        if (is_array($params) and !empty($params)) {

            $terms = array();

            $alt_predicate = '';

            $other_predicate = '';

            foreach ($params as $key => $value) {

                if ($key == 'rel' && $value == 'alternate') {

                    $alt_predicate = '[not(@rel) or @rel="alternate"]';

                } else {

                    $terms[] = "@$key='$value'";

                }

            }

            if (!empty($terms)) {

                $other_predicate = '[' . join(' and ', $terms) . ']';

            }

            $query =  $this->xpathPrefix . 'atom:link' . $alt_predicate . $other_predicate;

            $links = $this->xpath->query($query);

        } else {

            $links = $this->model->getElementsByTagName('link');

        }

        if ($links->length > $offset) {

            if ($links->item($offset)->hasAttribute($attribute)) {

                $value = $links->item($offset)->getAttribute($attribute);

                if ($attribute == 'href') {

                    $value = $this->addBase($value, $links->item($offset));

                }

                return $value;

            } else if ($attribute == 'rel') {

                return 'alternate';

            }

        }

        return false;

    }

}

?>