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<?php

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

/**

 * Abstract class providing common methods for XML_Feed_Parser feeds.

 *

 * 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: Type.php,v 1.2 2007-07-25 15:05:34 jp_milcent Exp $

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

 */

/**

 * This abstract class provides some general methods that are likely to be

 * implemented exactly the same way for all feed types.

 *

 * @package XML_Feed_Parser

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

 * @version Release: 1.0.2

 */

abstract class XML_Feed_Parser_Type

{

    /**

     * Where we store our DOM object for this feed

     * @var DOMDocument

     */

    public $model;

    /**

     * For iteration we'll want a count of the number of entries

     * @var int

     */

    public $numberEntries;

    /**

     * Where we store our entry objects once instantiated

     * @var array

     */

    public $entries = array();

    /**

     * Proxy to allow use of element names as method names

     *

     * We are not going to provide methods for every entry type so this

     * function will allow for a lot of mapping. We rely pretty heavily

     * on this to handle our mappings between other feed types and atom.

     *

     * @param   string  $call - the method attempted

     * @param   array   $arguments - arguments to that method

     * @return  mixed

     */

    function __call($call, $arguments = array())

    {

        if (! is_array($arguments)) {

            $arguments = array();

        }

        if (isset($this->compatMap[$call])) {

            $tempMap = $this->compatMap;

            $tempcall = array_pop($tempMap[$call]);

            if (! empty($tempMap)) {

                $arguments = array_merge($arguments, $tempMap[$call]);

            }

            $call = $tempcall;

        }

        /* To be helpful, we allow a case-insensitive search for this method */

        if (! isset($this->map[$call])) {

            foreach (array_keys($this->map) as $key) {

                if (strtoupper($key) == strtoupper($call)) {

                    $call = $key;

                    break;

                }

            }

        }

        if (empty($this->map[$call])) {

            return false;

        }

        $method = 'get' . $this->map[$call][0];

        if ($method == 'getLink') {

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

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

            $params = isset($arguments[2]) ? $arguments[2] : array();

            return $this->getLink($offset, $attribute, $params);

        }

        if (method_exists($this, $method)) {

            return $this->$method($call, $arguments);

        }

        return false;

    }

    /**

     * Proxy to allow use of element names as attribute names

     *

     * For many elements variable-style access will be desirable. This function

     * provides for that.

     *

     * @param   string  $value - the variable required

     * @return  mixed

     */

    function __get($value)

    {

        return $this->__call($value, array());

    }

    /**

     * Utility function to help us resolve xml:base values

     *

     * We have other methods which will traverse the DOM and work out the different

     * xml:base declarations we need to be aware of. We then need to combine them.

     * If a declaration starts with a protocol then we restart the string. If it

     * starts with a / then we add on to the domain name. Otherwise we simply tag

     * it on to the end.

     *

     * @param   string  $base - the base to add the link to

     * @param   string  $link

     */

    function combineBases($base, $link)

    {

        if (preg_match('/^[A-Za-z]+:\/\//', $link)) {

            return $link;

        } else if (preg_match('/^\//', $link)) {

            /* Extract domain and suffix link to that */

            preg_match('/^([A-Za-z]+:\/\/.*)?\/*/', $base, $results);

            $firstLayer = $results[0];

            return $firstLayer . "/" . $link;

        } else if (preg_match('/^\.\.\//', $base)) {

            /* Step up link to find place to be */

            preg_match('/^((\.\.\/)+)(.*)$/', $link, $bases);

            $suffix = $bases[3];

            $count = preg_match_all('/\.\.\//', $bases[1], $steps);

            $url = explode("/", $base);

            for ($i = 0; $i <= $count; $i++) {

                array_pop($url);

            }

            return implode("/", $url) . "/" . $suffix;

        } else if (preg_match('/^(?!\/$)/', $base)) {

            $base = preg_replace('/(.*\/).*$/', '$1', $base)  ;

            return $base . $link;

        } else {

            /* Just stick it on the end */

            return $base . $link;

        }

    }

    /**

     * Determine whether we need to apply our xml:base rules

     *

     * Gets us the xml:base data and then processes that with regard

     * to our current link.

     *

     * @param   string

     * @param   DOMElement

     * @return  string

     */

    function addBase($link, $element)

    {

        if (preg_match('/^[A-Za-z]+:\/\//', $link)) {

            return $link;

        }

        return $this->combineBases($element->baseURI, $link);

    }

    /**

     * Get an entry by its position in the feed, 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

     * @return  XML_Feed_Parser_RSS1Element

     */

    function getEntryByOffset($offset)

    {

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

            $entries = $this->model->getElementsByTagName($this->itemElement);

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

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

                $this->entries[$offset] = new $this->itemClass(

                    $entries->item($offset), $this, $xmlBase);

                if ($id = $this->entries[$offset]->id) {

                    $id_mappings = $this->idMappings;

                    $id_mappings[$id] = $this->entries[$offset];

                    $this->idMappings = $id_mappings;

                }

            } else {

                throw new XML_Feed_Parser_Exception('No entries found');

            }

        }

        return $this->entries[$offset];

    }

    /**

     * Return a date in seconds since epoch.

     *

     * Get a date construct. We use PHP's strtotime to return it as a unix datetime, which

     * is the number of seconds since 1970-01-01 00:00:00.

     *

     * @link    http://php.net/strtotime

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

     * @param    array     $arguments    Included for compatibility with our __call usage

     * @return    int|false datetime

     */

    protected function getDate($method, $arguments)

    {

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

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

            return false;

        }

        return strtotime($time->item(0)->nodeValue);

    }

    /**

     * Get a text construct.

     *

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

     * @param    array     $arguments    Included for compatibility with our __call usage

     * @return    string

     */

    protected function getText($method, $arguments = array())

    {

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

        if ($tags->length > 0) {

            $value = $tags->item(0)->nodeValue;

            return $value;

        }

        return false;

    }

    /**

     * Apply various rules to retrieve category data.

     *

     * There is no single way of declaring a category in RSS1/1.1 as there is in RSS2

     * and  Atom. Instead the usual approach is to use the dublin core namespace to

     * declare  categories. For example delicious use both:

     * <dc:subject>PEAR</dc:subject> and: <taxo:topics><rdf:Bag>

     * <rdf:li resource="http://del.icio.us/tag/PEAR" /></rdf:Bag></taxo:topics>

     * to declare a categorisation of 'PEAR'.

     *

     * We need to be sensitive to this where possible.

     *

     * @param    string    $call    for compatibility with our overloading

     * @param   array $arguments - arg 0 is the offset, arg 1 is whether to return as array

     * @return  string|array|false

     */

    protected function getCategory($call, $arguments)

    {

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

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

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

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

            return false;

        }

        if ($array) {

            $list = array();

            foreach ($categories as $category) {

                array_push($list, $category->nodeValue);

            }

            return $list;

        }

        return $categories->item($offset)->nodeValue;

    }

    /**

     * Count occurrences of an element

     *

     * This function will tell us how many times the element $type

     * appears at this level of the feed.

     *

     * @param    string    $type    the element we want to get a count of

     * @return    int

     */

    protected function count($type)

    {

        if ($tags = $this->model->getElementsByTagName($type)) {

            return $tags->length;

        }

        return 0;

    }

    /**

     * Part of our xml:base processing code

     *

     * We need a couple of methods to access XHTML content stored in feeds.

     * This is because we dereference all xml:base references before returning

     * the element. This method handles the attributes.

     *

     * @param   DOMElement $node    The DOM node we are iterating over

     * @return  string

     */

    function processXHTMLAttributes($node) {

        $return = '';

        foreach ($node->attributes as $attribute) {

            if ($attribute->name == 'src' or $attribute->name == 'href') {

                $attribute->value = $this->addBase($attribute->value, $attribute);

            }

            if ($attribute->name == 'base') {

                continue;

            }

            $return .= $attribute->name . '="' . $attribute->value .'" ';

        }

        if (! empty($return)) {

            return ' ' . trim($return);

        }

        return '';

    }

    /**

     * Part of our xml:base processing code

     *

     * We need a couple of methods to access XHTML content stored in feeds.

     * This is because we dereference all xml:base references before returning

     * the element. This method recurs through the tree descending from the node

     * and builds our string

     *

     * @param   DOMElement $node    The DOM node we are processing

     * @return   string

     */

    function traverseNode($node)

    {

        $content = '';

        /* Add the opening of this node to the content */

        if ($node instanceof DOMElement) {

            $content .= '<' . $node->tagName .

                $this->processXHTMLAttributes($node) . '>';

        }

        /* Process children */

        if ($node->hasChildNodes()) {

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

                $content .= $this->traverseNode($child);

            }

        }

        if ($node instanceof DOMText) {

            $content .= htmlentities($node->nodeValue);

        }

        /* Add the closing of this node to the content */

        if ($node instanceof DOMElement) {

            $content .= '</' . $node->tagName . '>';

        }

        return $content;

    }

    /**

     * Get content from RSS feeds (atom has its own implementation)

     *

     * The official way to include full content in an RSS1 entry is to use

     * the content module's element 'encoded', and RSS2 feeds often duplicate that.

     * Often, however, the 'description' element is used instead. We will offer that

     * as a fallback. Atom uses its own approach and overrides this method.

     *

     * @return  string|false

     */

    protected function getContent()

    {

        $options = array('encoded', 'description');

        foreach ($options as $element) {

            $test = $this->model->getElementsByTagName($element);

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

                continue;

            }

            if ($test->item(0)->hasChildNodes()) {

                $value = '';

                foreach ($test->item(0)->childNodes as $child) {

                    if ($child instanceof DOMText) {

                        $value .= $child->nodeValue;

                    } else {

                        $simple = simplexml_import_dom($child);

                        $value .= $simple->asXML();

                    }

                }

                return $value;

            } else if ($test->length > 0) {

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

            }

        }

        return false;

    }

    /**

     * Checks if this element has a particular child element.

     *

     * @param   String

     * @param   Integer

     * @return  bool

     **/

    function hasKey($name, $offset = 0)

    {

        $search = $this->model->getElementsByTagName($name);

        return $search->length > $offset;

    }

    /**

     * Return an XML serialization of the feed, should it be required. Most

     * users however, will already have a serialization that they used when

     * instantiating the object.

     *

     * @return    string    XML serialization of element

     */

    function __toString()

    {

        $simple = simplexml_import_dom($this->model);

        return $simple->asXML();

    }

    /**

     * Get directory holding RNG schemas. Method is based on that

     * found in Contact_AddressBook.

     *

     * @return string PEAR data directory.

     * @access public

     * @static

     */

    static function getSchemaDir()

    {

        require_once 'PEAR/Config.php';

        $config = new PEAR_Config;

        return $config->get('data_dir') . '/XML_Feed_Parser/schemas';

    }

}

?>