<?php

/**
 * @file
 * Hooks provided by the XML-RPC module.
 */

/**
 * Register XML-RPC callbacks.
 *
 * This hook lets a module register callback functions to be called when
 * particular XML-RPC methods are invoked by a client.
 *
 * @return
 *   An array which maps XML-RPC methods to Drupal functions. Each array
 *   element is either a pair of method => function or an array with four
 *   entries:
 *   - The XML-RPC method name (for example, module.function).
 *   - The Drupal callback function (for example, module_function).
 *   - The method signature is an array of XML-RPC types. The first element
 *     of this array is the type of return value and then you should write a
 *     list of the types of the parameters. XML-RPC types are the following
 *     (See the types at http://www.xmlrpc.com/spec):
 *       - "boolean": 0 (false) or 1 (true).
 *       - "double": a floating point number (for example, -12.214).
 *       - "int": a integer number (for example,  -12).
 *       - "array": an array without keys (for example, array(1, 2, 3)).
 *       - "struct": an associative array or an object (for example,
 *          array('one' => 1, 'two' => 2)).
 *       - "date": when you return a date, then you may either return a
 *          timestamp (time(), mktime() etc.) or an ISO8601 timestamp. When
 *          date is specified as an input parameter, then you get an object,
 *          which is described in the function xmlrpc_date
 *       - "base64": a string containing binary data, automatically
 *          encoded/decoded automatically.
 *       - "string": anything else, typically a string.
 *   - A descriptive help string, enclosed in a t() function for translation
 *     purposes.
 *   Both forms are shown in the example.
 */
function hook_xmlrpc() {
  return array(
    'drupal.login' => 'drupal_login',
    array(
      'drupal.site.ping',
      'drupal_directory_ping',
      array('boolean', 'string', 'string', 'string', 'string', 'string'),
      t('Handling ping request'))
  );
}

/**
 * Alters the definition of XML-RPC methods before they are called.
 *
 * This hook allows modules to modify the callback definition of declared
 * XML-RPC methods, right before they are invoked by a client. Methods may be
 * added, or existing methods may be altered.
 *
 * Note that hook_xmlrpc() supports two distinct and incompatible formats to
 * define a callback, so care must be taken when altering other methods.
 *
 * @param $methods
 *   An asssociative array of method callback definitions, as returned from
 *   hook_xmlrpc() implementations.
 *
 * @see hook_xmlrpc()
 * @see xmlrpc_server()
 */
function hook_xmlrpc_alter(&$methods) {
  // Directly change a simple method.
  $methods['drupal.login'] = 'mymodule_login';

  // Alter complex definitions.
  foreach ($methods as $key => &$method) {
    // Skip simple method definitions.
    if (!is_int($key)) {
      continue;
    }
    // Perform the wanted manipulation.
    if ($method[0] == 'drupal.site.ping') {
      $method[1] = 'mymodule_directory_ping';
    }
  }
}