Can we change the schema in services module?

Question

I am new to Drupal services; I have the below XML format, in which I need to expose nodes as services.

Can I do this using the Services module?

    <?xml version="1.0" encoding="UTF-8"?>
<ngd:mediafile xmlns:ngd="http://www.xyzy.com/ngdine"
               xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
               xsi:schemaLocation="http://www.xyzy.com/ngdine mediafile.xsd">
  <ngd:description>
    <![CDATA[This is the description]]>
  </ngd:description>
  <ngd:mediatype id="1"/>
  <ngd:internal>Aalborg city.JPG</ngd:internal>
</ngd:mediafile>

Can I change the schema?

Answer 1

If you need to expose the output that way, THeres 2 ways you can do it. You can alter the response before it gets sent as a payload, or you can write your own Response Format.

Both should do what you need, but its merely a preference.

/**
 * Triggered when the REST server request a list of supported response formats.
 *
 * @param array $formatters
 *  An associative array of formatter info arrays keyed by type extension. The
 *  formatter info specifies an array of 'mime types' that corresponds to the
 *  output format; a 'view' class that is a subclass of RESTServerView; and
 *  'view arguments' that should be passed to the view when it is created;
 *  a 'model' can also be specified which the controller then must declare
 *  support for to be able to serve data in that format.
 * @return void
 */
 function hook_rest_server_response_formatters_alter(&$formatters) {
   /*
    * Sample modifications of the formatters array. Both yaml and
    * rss are formats that already are supported, so the changes are
    * nonsensical but illustrates the proper use of this hook.
    */

    // Add a Yaml response format.
    $formatters['yaml'] = array(
      'mime types' => array('text/plain', 'application/x-yaml', 'text/yaml'),
      'view' => 'RESTServerViewBuiltIn',
      'view arguments' => array('format' => 'yaml'),
    );

    // Add a Rss response format.
    $formatters['rss'] = array(
     'model' => 'ResourceFeedModel',
     'mime types' => array('text/xml'),
     'view' => 'RssFormatView',
    );
 }

The altering of the response is, function HOOK_services_request_postprocess_alter

Answer 2

Besides retrieving content as XML, do you need any other functionality provided by the Services module? If not, it might be overkill.

One simple alternative might be to write a module that implements hook_menu() to define a menu item for a wildcard path such as node/%/xml, which then, in its page callback, outputs the XML in your specified format.

In Drupal 7, you might do this as follows:

<?php

function mymodule_menu() {
  $items['node/%nid/xml'] = array(
    'page callback' => 'mymodule_xml_view',
    'page arguments' => array(1),
  );
  return $items;
}

function mymodule_xml_view($nid) {
  drupal_set_header('Content-Type: text/xml');

  echo '<?xml version="1.0" encoding="UTF-8"?>';
  echo '<ngd:mediafile ...>';
  echo '<nid>' . $nid . '</nid>';
  // ...
  echo '</ngd:mediafile>';

  drupal_exit();
}

Then, after enabling the new module, you can retrieve XML content by simply fetching, for example, URL http://example.com/node/42/xml .