Drupal services endpoint returns 404 : Could not find resource retrieve - web-services

Question

I followed this tutorial :
http://pingv.com/blog/an-introduction-drupal-7-restful-services
and seems everyone have the same problem as mine in the comments.
I made a rest service with drupal services module :
Server = REST
path = api/mohtadoon
mohtadoon_api.module file
<?php
/**
* Implements of hook_services_resources().
*/
function mohtadoon_api_services_resources() {
$api = array(
'mohtadoon' => array(
'operations' => array(
'retrieve' => array(
'help' => 'Retrieves mohtadoon data',
'callback' => 'mohtadoon_api_stories_retrieve',
'file' => array('file' => 'inc', 'module' => 'mohtadoon_api','name' => 'resources/mohtadoon_api'),
'access arguments' => array('access content'),
),
),
),
);
return $api;
}
mohtadoon_api.inc file in resources/mohtadoon_api path
<?php
function mohtadoon_api_stories_retrieve() {
return mohtadoon_api_find_stories();
}
function mohtadoon_api_find_stories() {
// Compose query
$query = db_select('node', 'n');
$query->join('node_revision', 'v', '(n.nid = v.nid) AND (n.vid = v.vid)');
$query->join('users', 'u', 'n.uid = u.uid');
$query->join('field_data_body', 'b', '((b.entity_type = \'node\') AND (b.entity_id = n.nid) AND (b.revision_id = n.vid))');
$query->fields('v', array('timestamp', 'title'));
$query->addField('u', 'name', 'author');
$query->addField('b', 'body_value', 'content');
$query->condition('n.type', 'stories', '=');
$items = $query->execute()->fetchAll();
return $items;
}
?>
when I access the path
http://localhost/mohtadoon01/?q=api/mohtadoon/retrieve
where mohtadoon01 is project path AND ?q= because
the request result is 404 Not found: Could not find resource retrieve.
why is this happens && how to debug something like this ... I didn't deal with drupal before and want to make only one get web service.

Answer 1

You likely need to url encode your string:
http://localhost/mohtadoon01/?q=api%2Fmohtadoon%2Fretrieve
Can't promise this will work though, depending on your drupal configuration.
Slashes are allowed in query string, as per RFC: http://ietf.org/rfc/rfc3986.txt, however many services out of the box do not: you may need to enable AllowEncodedSlashes.

Answer 2

I encountered exactly the same thing using Services 7.x-3.7. To understand the issue, I looked through the following file:
services/servers/rest_server/includes/RESTServer.inc
Given the definition of your service, the code exercised by GET requests for your resource should be:
protected function resolveController($resource, &$operation) {
...
if ( $request_method == 'GET'
&& $canon_path_count >= 1
&& isset($resource['operations']['retrieve'])
&& $this->checkNumberOfArguments($canon_path_count, $resource['operations']['retrieve'])
&& !empty($canonical_path_array[0])
) {
$operation_type = 'operations';
$operation = 'retrieve';
}
...
}
If we now take a look at the code for $this->checkNumberOfArguments():
// We can see from the snippet above that $args_number = $canon_path_count and hence that
// $args_number is always greater than 0
protected function checkNumberOfArguments($args_number, $resource_operation, $required_args = 0) {
$not_required_args = 0;
if (isset($resource_operation['args'])) {
foreach ($resource_operation['args'] as $argument) {
if (isset($argument['source']) && is_array($argument['source']) && isset($argument['source']['path'])) {
if (!empty($argument['optional'])) {
$not_required_args++;
}
else {
$required_args++;
}
}
}
}
// This is where we fall down; Since the service definition does not include any args,
// both $required_args and $not_required_args will equal zero when we get here. Not a problem
// for the first condition (1 >= 0), but clearly the second condition (1 <= 0 + 0) will evaluate
// to false and hence the argument count will not be accepted. As a result, the services module
// does not accept this controller and reports this as '404 not found'
return $args_number >= $required_args && $args_number <= $required_args + $not_required_args;
}
Try adding an argument to your service definition like this:
<?php
/**
* Implements of hook_services_resources().
*/
function mohtadoon_api_services_resources() {
$api = array(
'mohtadoon' => array(
'operations' => array(
'retrieve' => array(
'help' => 'Retrieves mohtadoon data',
'callback' => 'mohtadoon_api_stories_retrieve',
'file' => array('file' => 'inc', 'module' => 'mohtadoon_api','name' => 'resources/mohtadoon_api'),
'access arguments' => array('access content'),
'arg' => array(
array(
'name' => 'entity',
'type' => 'string',
'description' => 'Entity to operate on',
'source' => array('path' => '0'),
'optional' => TRUE,
'default' => '0',
),
),
),
),
),
);
return $api;
}
EDIT:
I think what is confusing people reading the blog post that you linked to (and I was one of those!) is that the URL given as the accessor for the service includes as its final parameter the name of the method that it was intended to invoke ('retrieve'). You could replace 'retrieve' with pretty much anything and the service should still respond (e.g. '/api/blog/pink-rabbit' or, in your case, 'api/mohtadoon/pink-rabbit'). The web service definitions themselves do not indicate what value of parameters can be passed to the endpoint. What counts is what HTTP method is used to access the service and how many parameters are passed to the endpoint (zero or more). Some types of operation require at least a certain number of parameters (e.g. 'retrieve' operations require at least one parameter to identify the specific thing that you want to retrieve).