<?php

/*
 * get_steam_button
 * Returns a "Sign in through steam" button that will take you to the steam website to login, and then load the callback page.
 * Note that although it says openid in a lot of places, it's not following the openid spec and won't work with most if not all openid libraries
 * This assumes that you have a page at /steam_openid to take the callback
 */

function get_steam_button() {
      return '<a id="openid_link" href="https://steamcommunity.com/openid/login?openid.ns=http://specs.openid.net/auth/2.0&openid.mode=checkid_setup&openid.return_to=' . $base_url . $base_path . 'steam_openid/;&openid.realm=' . $base_url . '&openid.identity=http://specs.openid.net/auth/2.0/identifier_select&openid.claimed_id=http://specs.openid.net/auth/2.0/identifier_select">
  <img src="http://steamcommunity.com/public/images/signinthroughsteam/sits_small.png" />
  </a>',
    );
  }
}


/*
 * steam_openid
 * This is an example callback for the steam_openid page
 */

function steam_openid() {
  if(!isset($_GET['openid_assoc_handle']))
      return "Error attempting to validate your steam account, please try again.";

  $params = array(
      'openid.assoc_handle' => $_GET['openid_assoc_handle'],
      'openid.signed'           => $_GET['openid_signed'],
      'openid.sig'          => $_GET['openid_sig'],
      'openid.ns'               => 'http://specs.openid.net/auth/2.0',
  );

  $signed = explode(',', $_GET['openid_signed']);
  foreach($signed as $item)
  {
      $val = $_GET['openid_' . str_replace('.', '_', $item)];
      $params['openid.' . $item] = get_magic_quotes_gpc() ? stripslashes($val) : $val;
  }

  $params['openid.mode'] = 'check_authentication';

  $data =  http_build_query($params);
  $context = stream_context_create(array(
      'http' => array(
          'method'  => 'POST',
          'header'  =>
              "Accept-language: en\r\n".
              "Content-type: application/x-www-form-urlencoded\r\n" .
              "Content-Length: " . strlen($data) . "\r\n",
          'content' => $data,
      ),
  ));

  $result = file_get_contents("https://steamcommunity.com/openid/login", false, $context);

  preg_match("#^http://steamcommunity.com/openid/id/([0-9]{17,25})#", $_GET['openid_claimed_id'], $matches);
  $steamid64 = is_numeric($matches[1]) ? $matches[1] : 0;

  if (preg_match("#is_valid\s*:\s*true#i", $result) != 1) {
    global $base_url;
    global $base_path;
    header("Location: https://steamcommunity.com/openid/login?openid.ns=http://specs.openid.net/auth/2.0&openid.mode=checkid_setup&openid.return_to=' . $base_url . $base_path . 'steam_openid/&openid.realm=' . $base_url . '&openid.identity=http://specs.openid.net/auth/2.0/identifier_select&openid.claimed_id=http://specs.openid.net/auth/2.0/identifier_select");
      return "Error attempting to validate your steam account, please try again.";
  }
  // If you make it past the above link, you've got a validated steam account. $steamid64 is like a $user->id for steam accounts, so it's the main thing you'll want to store.
  return "You have successfully linked your steam account.";
}

/*
 * Load steam XML
 * Call this function with the steamid64 obtained from steam_openid to load the XML feed for that user. This contains name, avatar, and lots of other information
 */

function steam_load_xml($steamid64) {
  $url = "http://steamcommunity.com/profiles/" . $steamid64 . "/?xml=1";
  $context = stream_context_create(array('http' => array('timeout' => 5)));
  if($fp = @fopen($url, 'r', FALSE, $context))
  {
    $xml = stream_get_contents($fp);
    fclose($fp);
    $xml = new SimpleXMLElement($xml);
    return $xml;
  }
  return FALSE;
}