Club Drupal

<?php

/**

 * @file

 * Provides a custom version of DOMXPath for use with feeds_xpathparser.

 */

/**

 * Wraps DOMXPath providing enhanced debugging and special namespace handling.

 */

class FeedsXPathParserDOMXPath extends DOMXPath {

  /**

   * The DOMDocument to parse.

   *

   * @var DOMDocument

   */

  protected $doc;

  /**

   * Configuration array.

   *

   * @var array

   */

  protected $config = array();

  /**

   * Modified query cache.

   *

   * @var arrray

   */

  protected $modifiedQueries = array();

  /**

   * The namespaces in the document.

   *

   * @var arrray

   */

  protected $namespaces = array();

  /**

   * The most recent error from parsing.

   *

   * @var stdClass

   */

  protected $error;

  /**

   * Constructs a FeedsXPathParserDOMXPath object.

   *

   * @param DOMDocument $doc

   *   The DOMDocument that we're operating on.

   */

  public function __construct(DOMDocument $doc) {

    $simple = simplexml_import_dom($doc);

    // An empty DOMDocument will make $simple NULL.

    if ($simple !== NULL) {

      $this->namespaces = $simple->getNamespaces(TRUE);

    }

    $this->doc = $doc;

    parent::__construct($doc);

  }

  /**

   * Sets the extended configuration.

   *

   * @param array $config

   *   The config array.

   */

  public function setConfig(array $config) {

    $this->config = $config;

  }

  /**

   * Renders our debug messages into a list.

   *

   * @param mixed $data

   *   The result of an XPath query. Either a scalar or a DOMNodeList.

   * @param string $source

   *   The source key that produced this query.

   *

   * @todo Use theme_item_list().

   */

  protected function debug($data, $source) {

    $output = "$source : <ul>";

    if ($data instanceof DOMNodeList) {

      foreach ($data as $node) {

        $output .= '<li>' . check_plain($this->doc->saveXML($node)) . '</li>';

      }

    }

    else {

      $output .= '<li>' . check_plain($data) . '</li>';

    }

    $output .= '</ul>';

    drupal_set_message($output);

  }

  /**

   * Executes an XPath query with namespace support.

   *

   * @param string $query

   *   An XPath query.

   * @param DOMNode $context

   *   The current context of the XPath query.

   * @param string $source

   *   The source key for this query.

   *

   * @return array

   *   An array containing the results of the query.

   */

  public function namespacedQuery($query, $context, $source) {

    $this->addDefaultNamespace($query);

    $results = $this->executeQuery($query, $context);

    if (in_array($source, $this->config['debug'])) {

      $this->debug($results, $source);

    }

    if (is_object($this->error) && $this->config['errors']) {

      if ($this->error->level == LIBXML_ERR_ERROR) {

        drupal_set_message(

          t('There was an error during the XPath query: %query.<br />Libxml returned the message: %message, with the error code: %code.', array(

            '%query' => $query,

            '%message' => trim($this->error->message),

            '%code' => $this->error->code,

          )),

          'error',

          FALSE);

      }

      elseif ($this->error->level == LIBXML_ERR_WARNING) {

        drupal_set_message(

          t('There was an error during the XPath query: %query.<br />Libxml returned the message: %message, with the error code: %code.', array(

            '%query' => $query,

            '%message' => trim($this->error->message),

            '%code' => $this->error->code,

          )),

          'warning',

          FALSE);

      }

    }

    // DOMXPath::evaluate() and DOMXPath::query() will return FALSE on error or

    // if the value is FALSE. We check error result and return NULL in case

    // of error.

    if (is_object($this->error) && $this->error->level == LIBXML_ERR_ERROR) {

      return NULL;

    }

    return $results;

  }

  /**

   * Normalizes XPath queries, adding the default namespace.

   *

   * @param string $query

   *   An XPath query string

   */

  protected function addDefaultNamespace(&$query) {

    foreach ($this->namespaces as $prefix => $namespace) {

      if ($prefix === '') {

        $this->registerNamespace('__default__', $namespace);

        // Replace all the elements without prefix by the default prefix.

        if (!isset($this->modifiedQueries[$query])) {

          $parser = new FeedsXPathParserQueryParser($query);

          $mod_query = $parser->getQuery();

          $this->modifiedQueries[$query] = $mod_query;

          $query = $mod_query;

        }

        else {

          $query = $this->modifiedQueries[$query];

        }

      }

      else {

        $this->registerNamespace($prefix, $namespace);

      }

    }

  }

  /**

   * Performs a XPath query.

   *

   * Here we set libxml_use_internal_errors() to TRUE because depending on the

   * libxml version, $xml->xpath() might return FALSE or an empty array() when

   * a query doesn't match.

   *

   * @param string $query

   *   The XPath query string.

   * @param DOMNode $context

   *   (optional) A context object. Defaults to NULL.

   *

   * @return mixed

   *   The result of the XPath query.

   */

  protected function executeQuery($query, DOMNode $context = NULL) {

    $use_errors = libxml_use_internal_errors(TRUE);

    // Perfom XPath query.

    // So, grrr. FALSE is returned when there is an error. However, FALSE is

    // also a valid return value from DOMXPath::evaluate(). Ex: '1 = 2'

    if ($context) {

      $results = $this->evaluate($query, $context);

    }

    else {

      $results = $this->query($query);

    }

    $this->error = libxml_get_last_error();

    libxml_clear_errors();

    libxml_use_internal_errors($use_errors);

    return $results;

  }

}