MicrodataPhp.php

<?php
/**
 * MicrodataPHP
 * http://github.com/linclark/MicrodataPHP
 * Copyright (c) 2011 Lin Clark
 * Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php
 *
 * Based on MicrodataJS
 * http://gitorious.org/microdatajs/microdatajs
 * Copyright (c) 2009-2011 Philip Jägenstedt
 */

namespace linclark\MicrodataPHP;

/**
 * Extracts microdata from HTML.
 *
 * Currently supported formats:
 *   - PHP object
 *   - JSON
 */
class MicrodataPhp {
  public $dom;

  /**
   * Constructs a MicrodataPhp object.
   *
   * @param array|string $config
   *   The configuration options used in setting up the MicrodataPhpDOMDocument.
   *   Options include:
   *   - url: The url of the page to fetch.
   *   - html: Alternatively, an HTML string can be used to set up the DOM.
   *
   * @throws \InvalidArgumentException
   */
  public function __construct($config) {
    // Convert a string to a config object for backwards compatibility.
    if (is_string($config)) {
      $config = array('url' => $config);
    }

    $dom = new MicrodataPhpDOMDocument();
    $dom->registerNodeClass('DOMDocument', 'linclark\MicrodataPHP\MicrodataPhpDOMDocument');
    $dom->registerNodeClass('DOMElement', 'linclark\MicrodataPHP\MicrodataPhpDOMElement');
    $dom->preserveWhiteSpace = false;

    // Prepare the DOM using either the URL or HTML string.
    if (isset($config['url'])) {
      @$dom->loadHTMLFile($config['url']);
    }
    else if (isset($config['html'])) {
      @$dom->loadHTML($config['html']);
    }
    else {
      throw new \InvalidArgumentException("Either a URL or an HTML string must be passed into the constructor.");
    }

    $this->dom = $dom;
  }

  /**
   * Retrieve microdata as a PHP object.
   *
   * @return object
   *   An object with an 'items' property, which is an array of top level
   *   microdata items as objects with the following properties:
   *   - type: An array of itemtype(s) for the item, if specified.
   *   - id: The itemid of the item, if specified.
   *   - properties: An array of itemprops. Each itemprop is keyed by the
   *     itemprop name and has its own array of values. Values can be strings
   *     or can be other items, represented as objects.
   *
   * @todo MicrodataJS allows callers to pass in a selector for limiting the
   *   parsing to one section of the document. Consider adding such
   *   functionality.
   */
  public function obj() {
    $result = new \stdClass();
    $result->items = array();
    foreach ($this->dom->getItems() as $item) {
      array_push($result->items, $this->getObject($item, array()));
    }
    return $result;
  }

  /**
   * Retrieve microdata in JSON format.
   *
   * @return string
   *   See obj().
   *
   * @todo MicrodataJS allows callers to pass in a function to format the JSON.
   * Consider adding such functionality.
   */
  public function json() {
    return json_encode($this->obj());
  }

  /**
   * Helper function.
   *
   * In MicrodataJS, this is handled using a closure. PHP 5.3 allows closures,
   * but cannot use $this within the closure. PHP 5.4 reintroduces support for
   * $this. When PHP 5.3/5.4 are more widely supported on shared hosting,
   * this function could be handled with a closure.
   */
  protected function getObject($item, $memory) {
    $result = new \stdClass();
    $result->properties = array();

    // Add itemtype.
    if ($itemtype = $item->itemType()) {
      $result->type = $itemtype;
    }
    // Add itemid. 
    if ($itemid = $item->itemid()) {
      $result->id = $itemid;
    }
    // Add properties.
    foreach ($item->properties() as $elem) {
      if ($elem->itemScope()) {
        // Cannot use in_array() for comparison when values are arrays, so
        // iterate and check for equality with each item in memory.
        foreach ($memory as $memory_item) {
          if ($memory_item === $elem) {
            $value = 'ERROR';
          }
        }
        // If the item is not in memory, there are no cycles, and thus no error.
        // Recurse into the item to build out its properties.
        if (!isset($value)) {
          $memory[] = $item;
          $value = $this->getObject($elem, $memory);
          array_pop($memory);
        }
      }
      else {
        $value = $elem->itemValue();
      }
      foreach ($elem->itemProp() as $prop) {
        $result->properties[$prop][] = $value;
      }

      $value = NULL;
    }
    return $result;
  }

}