-more REST

3 files changed, 315 insertions, 93 deletions

diff --git a/src/identity/plugin_rest_identity.c b/src/identity/plugin_rest_identity.c
index 75c65466c..d62e56db2 100644
--- a/src/identity/plugin_rest_identity.c
+++ b/src/identity/plugin_rest_identity.c
@@ -45,6 +45,8 @@
 
 #define GNUNET_REST_JSONAPI_IDENTITY_KEY "key"
 
+#define GNUNET_REST_JSONAPI_IDENTITY_SUBSYSTEM "subsystem"
+
 /**
  * @brief struct returned by the initialization function of the plugin
  */
@@ -236,16 +238,16 @@ get_ego_for_subsys (void *cls,
                     const char *name)
 {
   struct RequestHandle *handle = cls;
+  struct JsonApiObject *json_object;
+  struct JsonApiResource *json_resource;
   struct EgoEntry *ego_entry;
   struct MHD_Response *resp;
+  json_t *key_json;
   char *result_str;
   char *keystring;
-  json_t *ego_json;
-  json_t *root_json;
-
-  root_json = json_object ();
 
-  //Return all egos
+  json_object = GNUNET_REST_jsonapi_object_new ();
+  
   for (ego_entry = handle->ego_head;
        NULL != ego_entry;
        ego_entry = ego_entry->next)
@@ -254,26 +256,25 @@ get_ego_for_subsys (void *cls,
       continue;
     if (NULL == name)
       continue;
-    ego_json = json_object ();
+    json_resource = GNUNET_REST_jsonapi_resource_new (GNUNET_REST_JSONAPI_IDENTITY_EGO, ego_entry->identifier);
     keystring = GNUNET_CRYPTO_ecdsa_public_key_to_string (&ego_entry->pk);
-    json_object_set_new (ego_json, "id", json_string (ego_entry->identifier));
-    json_object_set_new (ego_json, "type", json_string (GNUNET_REST_JSONAPI_IDENTITY_EGO));
-    json_object_set_new (ego_json, "key", json_string (keystring));
+    key_json = json_string (keystring);
+    GNUNET_REST_jsonapi_resource_add_attr (json_resource, GNUNET_REST_JSONAPI_IDENTITY_KEY, key_json);
+    json_decref (key_json);
     GNUNET_free (keystring);
+    GNUNET_REST_jsonapi_object_resource_add (json_object, json_resource);
     break;
   }
-  if (NULL == ego_json)
+  if (0 == GNUNET_REST_jsonapi_object_resource_count (json_object))
   {
-    json_decref (root_json);
+    GNUNET_REST_jsonapi_object_delete (json_object);
     GNUNET_SCHEDULER_add_now (&do_error, handle);
     return;
   }
-  json_object_set (root_json, GNUNET_REST_JSONAPI_KEY_DATA, ego_json);
-  result_str = json_dumps (root_json, JSON_COMPACT);
+  GNUNET_REST_jsonapi_data_serialize (json_object, &result_str);
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Result %s\n", result_str);
-  json_decref (ego_json);
-  json_decref (root_json);
   resp = GNUNET_REST_create_json_response (result_str);
+  GNUNET_REST_jsonapi_object_delete (json_object);
   handle->proc (handle->proc_cls, resp, MHD_HTTP_OK);
   GNUNET_free (result_str);
   cleanup_handle (handle);
@@ -297,7 +298,7 @@ ego_info_response (struct RestConnectionDataHandle *con,
   struct EgoEntry *ego_entry;
   struct GNUNET_HashCode key;
   struct MHD_Response *resp;
-  struct JsonApiResponse *json_response;
+  struct JsonApiObject *json_object;
   struct JsonApiResource *json_resource;
   json_t *key_str;
 
@@ -309,7 +310,6 @@ ego_info_response (struct RestConnectionDataHandle *con,
     GNUNET_break (0);
     return;
   }
-  json_response = GNUNET_REST_jsonapi_response_new ();
   if ( (strlen (EGO_NAMESPACE) == strlen (handle->url) )) {
     GNUNET_CRYPTO_hash (URL_PARAM_SUBSYS, strlen (URL_PARAM_SUBSYS), &key);
     if ( GNUNET_YES ==
@@ -330,7 +330,7 @@ ego_info_response (struct RestConnectionDataHandle *con,
       }
     }
   }
-  json_response = GNUNET_REST_jsonapi_response_new ();
+  json_object = GNUNET_REST_jsonapi_object_new ();
   egoname = &handle->url[strlen (EGO_NAMESPACE)+1];
 
   if (strlen (EGO_NAMESPACE) == strlen (handle->url))
@@ -353,13 +353,13 @@ ego_info_response (struct RestConnectionDataHandle *con,
                                            key_str);
     json_decref (key_str);
     GNUNET_free (keystring);
-    GNUNET_REST_jsonapi_response_resource_add (json_response, json_resource);
+    GNUNET_REST_jsonapi_object_resource_add (json_object, json_resource);
   }
 
-  GNUNET_REST_jsonapi_data_serialize (json_response, &result_str);
-
+  GNUNET_REST_jsonapi_data_serialize (json_object, &result_str);
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Result %s\n", result_str);
   resp = GNUNET_REST_create_json_response (result_str);
+  GNUNET_REST_jsonapi_object_delete (json_object);
   handle->proc (handle->proc_cls, resp, MHD_HTTP_OK);
   GNUNET_free (result_str);
   cleanup_handle (handle);
@@ -421,16 +421,14 @@ ego_create_cont (struct RestConnectionDataHandle *con,
                  const char *url,
                  void *cls)
 {
-  const char* egoname;
   struct RequestHandle *handle = cls;
-  char term_data[handle->data_size+1];
   struct EgoEntry *ego_entry;
   struct MHD_Response *resp;
-  json_t *root_json;
-  json_t *data_json;
-  json_t *type_json;
+  struct JsonApiObject *json_obj;
+  struct JsonApiResource *json_res;
   json_t *egoname_json;
-  json_error_t error;
+  char term_data[handle->data_size+1];
+  const char* egoname;
 
   if (strlen (API_NAMESPACE) != strlen (handle->url))
   {
@@ -442,43 +440,39 @@ ego_create_cont (struct RestConnectionDataHandle *con,
     GNUNET_SCHEDULER_add_now (&do_error, handle);
     return;
   }
-
   term_data[handle->data_size] = '\0';
   memcpy (term_data, handle->data, handle->data_size);
-  root_json = json_loads (term_data, 0, &error);
+  json_obj = GNUNET_REST_jsonapi_object_parse (term_data);
 
-  if ((NULL == root_json) || !json_is_object (root_json))
+  if (NULL == json_obj)
   {
     GNUNET_SCHEDULER_add_now (&do_error, handle);
     return;
   }
-  data_json = json_object_get (root_json, GNUNET_REST_JSONAPI_KEY_DATA);
-  if ((NULL == data_json) || !json_is_object (data_json))
+  if (1 != GNUNET_REST_jsonapi_object_resource_count (json_obj))
   {
+    GNUNET_REST_jsonapi_object_delete (json_obj);
     GNUNET_SCHEDULER_add_now (&do_error, handle);
     return;
   }
-  type_json = json_object_get (data_json, "type");
-  if (!json_is_string (type_json) ||
-      (0 != strcmp (GNUNET_REST_JSONAPI_IDENTITY_EGO, json_string_value (type_json))))
+
+  json_res = GNUNET_REST_jsonapi_object_get_resource (json_obj, 0);
+  if (GNUNET_NO == GNUNET_REST_jsonapi_resource_check_type (json_res, GNUNET_REST_JSONAPI_IDENTITY_EGO))
   {
-    json_decref (data_json);
-    json_decref (root_json);
+    GNUNET_REST_jsonapi_object_delete (json_obj);
     resp = GNUNET_REST_create_json_response (NULL);
     handle->proc (handle->proc_cls, resp, MHD_HTTP_CONFLICT);
     cleanup_handle (handle);
     return;
   }
-  json_decref (type_json);
-  egoname_json = json_object_get (data_json, "id");
+  
+  egoname_json = GNUNET_REST_jsonapi_resource_read_attr (json_res, GNUNET_REST_JSONAPI_KEY_ID);
   if (!json_is_string (egoname_json))
   {
-    json_decref (data_json);
-    json_decref (root_json);
+    GNUNET_REST_jsonapi_object_delete (json_obj); 
     GNUNET_SCHEDULER_add_now (&do_error, handle);
     return;
   }
-
   egoname = json_string_value (egoname_json);
   for (ego_entry = handle->ego_head;
        NULL != ego_entry;
@@ -487,8 +481,7 @@ ego_create_cont (struct RestConnectionDataHandle *con,
     if (0 == strcasecmp (egoname, ego_entry->identifier))
     {
       json_decref (egoname_json);
-      json_decref (data_json);
-      json_decref (root_json);
+      GNUNET_REST_jsonapi_object_delete (json_obj);
       resp = GNUNET_REST_create_json_response (NULL);
       handle->proc (handle->proc_cls, resp, MHD_HTTP_CONFLICT);
       cleanup_handle (handle);
@@ -497,8 +490,7 @@ ego_create_cont (struct RestConnectionDataHandle *con,
   }
   GNUNET_asprintf (&handle->name, "%s", egoname);
   json_decref (egoname_json);
-  json_decref (data_json);
-  json_decref (root_json);
+  GNUNET_REST_jsonapi_object_delete (json_obj);
   handle->op = GNUNET_IDENTITY_create (handle->identity_handle,
                                        handle->name,
                                        &create_finished,
@@ -510,6 +502,8 @@ subsys_set_cont (struct RestConnectionDataHandle *con,
                  const char *url,
                  void *cls)
 {
+  struct JsonApiObject *json_obj;
+  struct JsonApiResource *json_res;
   const char *egoname;
   const char *subsys;
   struct RequestHandle *handle = cls;
@@ -517,13 +511,8 @@ subsys_set_cont (struct RestConnectionDataHandle *con,
   struct EgoEntry *ego_entry;
   struct MHD_Response *resp;
   int ego_exists = GNUNET_NO;
-  json_t *root_json;
-  json_t *data_json;
-  json_t *type_json;
-  json_t *id_json;
   json_t *subsys_json;
-  json_error_t error;
-
+  
   if (strlen (API_NAMESPACE) > strlen (handle->url))
   {
     GNUNET_SCHEDULER_add_now (&do_error, handle);
@@ -557,54 +546,47 @@ subsys_set_cont (struct RestConnectionDataHandle *con,
 
   term_data[handle->data_size] = '\0';
   memcpy (term_data, handle->data, handle->data_size);
-  root_json = json_loads (term_data, 0, &error);
+  json_obj = GNUNET_REST_jsonapi_object_parse (term_data);
 
-  if ((NULL == root_json) || !json_is_object (root_json))
+  if (NULL == json_obj)
   {
     GNUNET_SCHEDULER_add_now (&do_error, handle);
     return;
   }
-  data_json = json_object_get (root_json, "data");
-  if (!json_is_object (data_json))
+  if (1 != GNUNET_REST_jsonapi_object_resource_count (json_obj))
   {
-    json_decref (root_json);
+    GNUNET_REST_jsonapi_object_delete (json_obj);
     GNUNET_SCHEDULER_add_now (&do_error, handle);
     return;
   }
-  id_json = json_object_get (data_json, "id");
-  if (!json_is_string (id_json) ||
-      (0 != strcmp (egoname, json_string_value (id_json))))
+
+  json_res = GNUNET_REST_jsonapi_object_get_resource (json_obj, 0);
+  if (GNUNET_NO == GNUNET_REST_jsonapi_resource_check_id (json_res, egoname))
   {
-    json_decref (root_json);
-    json_decref (data_json);
+    GNUNET_REST_jsonapi_object_delete (json_obj);
     GNUNET_SCHEDULER_add_now (&do_error, handle);
     return;
   }
-  json_decref (id_json);
-
-  type_json = json_object_get (data_json, "type");
-  if (!json_is_string (type_json) ||
-      (0 != strcmp (GNUNET_REST_JSONAPI_IDENTITY_EGO, json_string_value (type_json))))
+  
+  if (GNUNET_NO == GNUNET_REST_jsonapi_resource_check_id (json_res, GNUNET_REST_JSONAPI_IDENTITY_EGO))
   {
-    json_decref (root_json);
-    json_decref (data_json);
+    GNUNET_REST_jsonapi_object_delete (json_obj);
     GNUNET_SCHEDULER_add_now (&do_error, handle);
     return;
   }
-  json_decref (type_json);
 
-  subsys_json = json_object_get (data_json, "subsystem");
+  subsys_json = GNUNET_REST_jsonapi_resource_read_attr (json_res, GNUNET_REST_JSONAPI_IDENTITY_SUBSYSTEM);
   if (!json_is_string (subsys_json))
   {
-    json_decref (root_json);
-    json_decref (data_json);
+    json_decref (subsys_json);
+    GNUNET_REST_jsonapi_object_delete (json_obj);
     GNUNET_SCHEDULER_add_now (&do_error, handle);
     return;
   }
   subsys = json_string_value (subsys_json);
   GNUNET_asprintf (&handle->subsys, "%s", subsys);
   json_decref (subsys_json);
-  json_decref (root_json);
+  GNUNET_REST_jsonapi_object_delete (json_obj);
   handle->op = GNUNET_IDENTITY_set (handle->identity_handle,
                                     handle->subsys,
                                     ego_entry->ego,
diff --git a/src/include/gnunet_rest_lib.h b/src/include/gnunet_rest_lib.h
index cc02f01d0..398cbfdbe 100644
--- a/src/include/gnunet_rest_lib.h
+++ b/src/include/gnunet_rest_lib.h
@@ -90,7 +90,7 @@ struct JsonApiResource;
 /**
  * Responses for JSON API
  */
-struct JsonApiResponse;
+struct JsonApiObject;
 
 /**
  * Create a JSON API resource
@@ -124,18 +124,64 @@ int
 GNUNET_REST_jsonapi_resource_add_attr (const struct JsonApiResource *resource,
                                        const char* key,
                                        json_t *json);
+/**
+ * Read a JSON API attribute
+ *
+ * @param res the JSON resource
+ * @param key the key for the attribute
+ * @return the json attr
+ */
+json_t*
+GNUNET_REST_jsonapi_resource_read_attr (const struct JsonApiResource *resource,
+                                       const char* key);
+
+
+/**
+ * Check a JSON API resource id
+ *
+ * @param res the JSON resource
+ * @param id the expected id
+ * @return GNUNET_YES if id matches
+ */
+int
+GNUNET_REST_jsonapi_resource_check_id (const struct JsonApiResource *resource,
+                                       const char* id);
+
 
 /**
+ * Check a JSON API resource type
+ *
+ * @param res the JSON resource
+ * @param type the expected type
+ * @return GNUNET_YES if id matches
+ */
+int
+GNUNET_REST_jsonapi_resource_check_type (const struct JsonApiResource *resource,
+                                         const char* type);
+
+  
+/**
  * Create a JSON API primary data
  *
  * @param type the JSON API resource type
  * @param id the JSON API resource id
  * @return a new JSON API resource or NULL on error.
  */
-struct JsonApiResponse*
-GNUNET_REST_jsonapi_response_new ();
+struct JsonApiObject*
+GNUNET_REST_jsonapi_object_new ();
+
 
 /**
+ * Create a JSON API primary data from a string
+ *
+ * @param data the string of the JSON API data
+ * @return a new JSON API resource or NULL on error.
+ */
+struct JsonApiObject*
+GNUNET_REST_jsonapi_object_parse (const char* data);
+
+  
+/**
  * Delete a JSON API primary data
  *
  * @param type the JSON API resource type
@@ -143,7 +189,7 @@ GNUNET_REST_jsonapi_response_new ();
  * @return a new JSON API resource or NULL on error.
  */
 void
-GNUNET_REST_jsonapi_response_delete (struct JsonApiResponse *resp);
+GNUNET_REST_jsonapi_object_delete (struct JsonApiObject *resp);
 
 /**
  * Add a JSON API resource to primary data
@@ -153,8 +199,27 @@ GNUNET_REST_jsonapi_response_delete (struct JsonApiResponse *resp);
  * @return the new number of resources
  */
 void
-GNUNET_REST_jsonapi_response_resource_add (struct JsonApiResponse *resp,
+GNUNET_REST_jsonapi_object_resource_add (struct JsonApiObject *resp,
                                            struct JsonApiResource *res);
+/**
+ * Get a JSON API object resource count
+ *
+ * @param resp the JSON API object
+ * @return the number of resources
+ */
+int
+GNUNET_REST_jsonapi_object_resource_count (struct JsonApiObject *resp);
+
+/**
+ * Get a JSON API object resource #num
+ *
+ * @param resp the JSON API object
+ * @param num the number of the resource
+ * @return the resource
+ */
+struct JsonApiResource*
+GNUNET_REST_jsonapi_object_get_resource (struct JsonApiObject *resp, int num);
+
 
 /**
  * Add a JSON API resource to primary data
@@ -164,7 +229,7 @@ GNUNET_REST_jsonapi_response_resource_add (struct JsonApiResponse *resp,
  * @return the new number of resources
  */
 void
-GNUNET_REST_jsonapi_data_resource_remove (struct JsonApiResponse *resp,
+GNUNET_REST_jsonapi_data_resource_remove (struct JsonApiObject *resp,
                                           struct JsonApiResource *res);
 
 /**
@@ -175,7 +240,7 @@ GNUNET_REST_jsonapi_data_resource_remove (struct JsonApiResponse *resp,
  * @return GNUNET_SYSERR on error else GNUNET_OK
  */
 int
-GNUNET_REST_jsonapi_data_serialize (const struct JsonApiResponse *resp,
+GNUNET_REST_jsonapi_data_serialize (const struct JsonApiObject *resp,
                                     char **result);
 
 /**
diff --git a/src/rest/rest.c b/src/rest/rest.c
index ec46e1273..d6fb8a2f3 100644
--- a/src/rest/rest.c
+++ b/src/rest/rest.c
@@ -50,7 +50,7 @@ struct JsonApiResource
 };
 
 
-struct JsonApiResponse
+struct JsonApiObject
 {
   /**
    * DLL Resource
@@ -135,26 +135,163 @@ GNUNET_REST_jsonapi_resource_add_attr (const struct JsonApiResource *resource,
   return GNUNET_OK;
 }
 
+/**
+ * Read a JSON API attribute
+ *
+ * @param res the JSON resource
+ * @param key the key for the attribute
+ * @return the json_t object
+ */
+json_t*
+GNUNET_REST_jsonapi_resource_read_attr (const struct JsonApiResource *resource,
+                                       const char* key)
+{
+  if ( (NULL == resource) ||
+       (NULL == key))
+    return NULL;
+  return json_object_get (resource->res_obj, key);
+}
+
+int
+check_resource_attr_str (const struct JsonApiResource *resource,
+                         const char* key,
+                         const char* attr)
+{
+  json_t *value;
+  if ( (NULL == resource) ||
+       (NULL == key) ||
+       (NULL == attr))
+    return GNUNET_NO;
+  value = json_object_get (resource->res_obj, key);
+  if (NULL == value)
+    return GNUNET_NO;
+  if (!json_is_string (value) ||
+      (0 != strcmp (attr, json_string_value(value))))
+  {
+    json_decref (value);
+    return GNUNET_NO;
+  }
+  json_decref (value);
+  return GNUNET_YES;
+}
+
+/**
+ * Check a JSON API resource id
+ *
+ * @param res the JSON resource
+ * @param id the expected id
+ * @return GNUNET_YES if id matches
+ */
+int
+GNUNET_REST_jsonapi_resource_check_id (const struct JsonApiResource *resource,
+                                       const char* id)
+{
+  return check_resource_attr_str (resource, id, GNUNET_REST_JSONAPI_KEY_ID);  
+}
 
 
+/**
+ * Check a JSON API resource type
+ *
+ * @param res the JSON resource
+ * @param type the expected type
+ * @return GNUNET_YES if id matches
+ */
+int
+GNUNET_REST_jsonapi_resource_check_type (const struct JsonApiResource *resource,
+                                         const char* type)
+{
+  return check_resource_attr_str (resource, type, GNUNET_REST_JSONAPI_KEY_TYPE);  
+}
+
 
 /**
  * Create a JSON API primary data
  *
- * @param type the JSON API resource type
- * @param id the JSON API resource id
  * @return a new JSON API resource or NULL on error.
  */
-struct JsonApiResponse*
-GNUNET_REST_jsonapi_response_new ()
+struct JsonApiObject*
+GNUNET_REST_jsonapi_object_new ()
 {
-  struct JsonApiResponse *result;
+  struct JsonApiObject *result;
 
-  result = GNUNET_new (struct JsonApiResponse);
+  result = GNUNET_new (struct JsonApiObject);
   result->res_count = 0;
   return result;
 }
 
+
+static void
+add_json_resource (struct JsonApiObject *obj,
+                   const json_t *res_json)
+{
+  struct JsonApiResource *res;
+  json_t *type_json;
+  json_t *id_json;
+
+  id_json = json_object_get (res_json, GNUNET_REST_JSONAPI_KEY_ID);
+  type_json = json_object_get (res_json, GNUNET_REST_JSONAPI_KEY_TYPE);
+
+  if (!json_is_string (id_json) || !json_is_string (type_json))
+    return;
+
+  res = GNUNET_new (struct JsonApiResource);
+  res->res_obj = json_deep_copy (res_json);
+  GNUNET_REST_jsonapi_object_resource_add (obj, res);
+}
+
+/**
+ * Create a JSON API primary data from a string
+ *
+ * @param data the string of the JSON API data
+ * @return a new JSON API resource or NULL on error.
+ */
+struct JsonApiObject*
+GNUNET_REST_jsonapi_object_parse (const char* data)
+{
+  struct JsonApiObject *result;
+  json_t *root_json;
+  json_t *data_json;
+  json_error_t error;
+  int res_count = 0;
+  int i;
+  
+  if (NULL == data)
+    return NULL;
+  root_json = json_loads (data, 0, &error);
+
+  if ( (NULL == root_json) || !json_is_object (root_json))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "json error: %s", error.text); 
+    return NULL;
+  }
+  data_json = json_object_get (root_json, GNUNET_REST_JSONAPI_KEY_DATA);
+  if (NULL == data_json)
+  {
+    json_decref (root_json);
+    return NULL;
+  }
+
+  result = GNUNET_new (struct JsonApiObject);
+  result->res_count = 0;
+  if (json_is_object (data_json))
+    add_json_resource (result, data_json);
+  else if (json_is_array (data_json))
+  {
+    res_count = json_array_size (data_json);
+    for (i = 0; i < res_count; i++)
+      add_json_resource (result, json_array_get (data_json, i));
+  }
+  json_decref (root_json);
+  if (0 == res_count)
+  {
+    GNUNET_free (result);
+    result = NULL;
+  }
+  return result;
+}
+
+
 /**
  * Delete a JSON API primary data
  *
@@ -163,7 +300,7 @@ GNUNET_REST_jsonapi_response_new ()
  * @return a new JSON API resource or NULL on error.
  */
 void
-GNUNET_REST_jsonapi_response_delete (struct JsonApiResponse *resp)
+GNUNET_REST_jsonapi_object_delete (struct JsonApiObject *resp)
 {
   struct JsonApiResource *res;
   
@@ -175,14 +312,14 @@ GNUNET_REST_jsonapi_response_delete (struct JsonApiResponse *resp)
 }
 
 /**
- * Add a JSON API resource to primary data
+ * Add a JSON API object to primary data
  *
  * @param data The JSON API data to add to
  * @param res the JSON API resource to add
  * @return the new number of resources
  */
 void
-GNUNET_REST_jsonapi_response_resource_add (struct JsonApiResponse *resp,
+GNUNET_REST_jsonapi_object_resource_add (struct JsonApiObject *resp,
                                            struct JsonApiResource *res)
 {
   GNUNET_CONTAINER_DLL_insert (resp->res_list_head,
@@ -192,6 +329,44 @@ GNUNET_REST_jsonapi_response_resource_add (struct JsonApiResponse *resp,
   resp->res_count++;
 }
 
+
+/**
+ * Get a JSON API object resource count
+ *
+ * @param resp the JSON API object
+ * @return the number of resources
+ */
+int
+GNUNET_REST_jsonapi_object_resource_count (struct JsonApiObject *resp)
+{
+  return resp->res_count++;
+}
+
+/**
+ * Get a JSON API object resource #num
+ *
+ * @param resp the JSON API object
+ * @param num the number of the resource
+ * @return the resource
+ */
+struct JsonApiResource*
+GNUNET_REST_jsonapi_object_get_resource (struct JsonApiObject *resp, int num)
+{
+  struct JsonApiResource *res;
+  int i;
+
+  if ((0 < resp->res_count) &&
+      (num < resp->res_count))
+    return NULL;
+  res = resp->res_list_head;
+  for (i = 0; i < num; i++)
+  {
+    res = res->next;
+  }
+  return res;
+}
+
+
 /**
  * Add a JSON API resource to primary data
  *
@@ -200,7 +375,7 @@ GNUNET_REST_jsonapi_response_resource_add (struct JsonApiResponse *resp,
  * @return the new number of resources
  */
 void
-GNUNET_REST_jsonapi_data_resource_remove (struct JsonApiResponse *resp,
+GNUNET_REST_jsonapi_data_resource_remove (struct JsonApiObject *resp,
                                           struct JsonApiResource *res)
 {
   GNUNET_CONTAINER_DLL_remove (resp->res_list_head,
@@ -217,7 +392,7 @@ GNUNET_REST_jsonapi_data_resource_remove (struct JsonApiResponse *resp,
  * @return GNUNET_SYSERR on error else GNUNET_OK
  */
 int
-GNUNET_REST_jsonapi_data_serialize (const struct JsonApiResponse *resp,
+GNUNET_REST_jsonapi_data_serialize (const struct JsonApiObject *resp,
                                     char **result)
 {
   struct JsonApiResource *res;