function _openid_select_service

Select a service element.

The procedure is described in OpenID Authentication 2.0, section 7.3.2.

A new entry is added to the returned array with the key 'version' and the value 1 or 2 specifying the protocol version used by the service.

Parameters

$services: An array of service arrays as returned by openid_discovery().

Return value

The selected service array, or NULL if no valid services were found.

File

drupal/core/modules/openid/openid.inc, line 199

OpenID utility functions.

Code

function _openid_select_service(array $services) {

  // Extensible Resource Identifier (XRI) Resolution Version 2.0, section 4.3.3:
  // Find the service with the highest priority (lowest integer value). If there
  // is a tie, select a random one, not just the first in the XML document.
  shuffle($services);
  $selected_service = NULL;
  $selected_type_priority = FALSE;

  // Search for an OP Identifier Element.
  foreach ($services as $service) {
    if (!empty($service['uri'])) {
      $type_priority = FALSE;
      if (in_array('http://specs.openid.net/auth/2.0/server', $service['types'])) {
        $service['version'] = 2;
        $type_priority = 1;
      }
      elseif (in_array('http://specs.openid.net/auth/2.0/signon', $service['types'])) {
        $service['version'] = 2;
        $type_priority = 2;
      }
      elseif (in_array(OPENID_NS_1_0, $service['types']) || in_array(OPENID_NS_1_1, $service['types'])) {
        $service['version'] = 1;
        $type_priority = 3;
      }
      if ($type_priority && (!$selected_service || $type_priority < $selected_type_priority || $type_priority == $selected_type_priority && $service['priority'] < $selected_service['priority'])) {
        $selected_service = $service;
        $selected_type_priority = $type_priority;
      }
    }
  }
  if ($selected_service) {

    // Unset SimpleXMLElement instances that cannot be saved in $_SESSION.
    unset($selected_service['xrd']);
    unset($selected_service['service']);
  }
  return $selected_service;
}