-start a lib for REST and json:api

6 files changed, 502 insertions, 90 deletions

diff --git a/src/identity/Makefile.am b/src/identity/Makefile.am
index 6aabddd39..b0e7645b0 100644
--- a/src/identity/Makefile.am
+++ b/src/identity/Makefile.am
@@ -32,6 +32,7 @@ libgnunet_plugin_rest_identity_la_SOURCES = \
   plugin_rest_identity.c
 libgnunet_plugin_rest_identity_la_LIBADD = \
   $(top_builddir)/src/identity/libgnunetidentity.la \
+        $(top_builddir)/src/rest/libgnunetrest.la \
   $(top_builddir)/src/util/libgnunetutil.la $(XLIBS) \
   $(LTLIBINTL) -ljansson -lmicrohttpd
 libgnunet_plugin_rest_identity_la_LDFLAGS = \
diff --git a/src/identity/plugin_rest_identity.c b/src/identity/plugin_rest_identity.c
index 1bc5f6fea..ea611128d 100644
--- a/src/identity/plugin_rest_identity.c
+++ b/src/identity/plugin_rest_identity.c
@@ -27,6 +27,7 @@
 #include "platform.h"
 #include "gnunet_rest_plugin.h"
 #include "gnunet_identity_service.h"
+#include "gnunet_rest_lib.h"
 #include "microhttpd.h"
 #include <jansson.h>
 
@@ -40,9 +41,9 @@
 
 #define URL_PARAM_SUBSYS "service"
 
-#define JSON_API_TYPE_EGO "ego"
+#define GNUNET_REST_JSONAPI_IDENTITY_EGO "ego"
 
-#define JSON_API_TYPE_DATA "data"
+#define GNUNET_REST_JSONAPI_IDENTITY_KEY "key"
 
 /**
  * @brief struct returned by the initialization function of the plugin
@@ -168,27 +169,6 @@ struct RequestHandle
 
 };
 
-/**
- * Create s JSON Response for MHD
- *
- * @param data the JSON to return (can be NULL)
- * @return a MHD_Response handle
- */
-struct MHD_Response*
-create_json_response (const char *data)
-{
-  size_t len;
-  if (NULL == data)
-    len = 0;
-  else
-    len = strlen (data);
-  struct MHD_Response *resp = MHD_create_response_from_buffer (len,
-                                                               (void*)data,
-                                                               MHD_RESPMEM_MUST_COPY);
-  MHD_add_response_header (resp,MHD_HTTP_HEADER_CONTENT_TYPE,"application/json");
-  return resp;
-}
-
 
 /**
  * Cleanup lookup handle
@@ -236,7 +216,7 @@ do_error (void *cls,
           const struct GNUNET_SCHEDULER_TaskContext *tc)
 {
   struct RequestHandle *handle = cls;
-  struct MHD_Response *resp = create_json_response (NULL);
+  struct MHD_Response *resp = GNUNET_REST_create_json_response (NULL);
   handle->proc (handle->proc_cls, resp, MHD_HTTP_BAD_REQUEST);
   cleanup_handle (handle);
 }
@@ -277,7 +257,7 @@ get_ego_for_subsys (void *cls,
     ego_json = json_object ();
     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 (JSON_API_TYPE_EGO));
+    json_object_set_new (ego_json, "type", json_string (GNUNET_REST_JSONAPI_IDENTITY_EGO));
     json_object_set_new (ego_json, "key", json_string (keystring));
     GNUNET_free (keystring);
     break;
@@ -288,43 +268,18 @@ get_ego_for_subsys (void *cls,
     GNUNET_SCHEDULER_add_now (&do_error, handle);
     return;
   }
-  json_object_set (root_json, JSON_API_TYPE_DATA, ego_json);
+  json_object_set (root_json, GNUNET_REST_JSONAPI_KEY_DATA, ego_json);
   result_str = json_dumps (root_json, JSON_COMPACT);
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Result %s\n", result_str);
   json_decref (ego_json);
   json_decref (root_json);
-  resp = create_json_response (result_str);
+  resp = GNUNET_REST_create_json_response (result_str);
   handle->proc (handle->proc_cls, resp, MHD_HTTP_OK);
   GNUNET_free (result_str);
   cleanup_handle (handle);
 }
 
 /**
- * Validate the namespace of the requested url
- * TODO move this to a lib
- *
- * @param url the url
- * @param ns the namespace
- */
-int
-check_namespace (const char *url, const char *ns)
-{
-  if (0 != strncmp (EGO_NAMESPACE, url, strlen (EGO_NAMESPACE)))
-  {
-    return GNUNET_NO;
-  }
-
-  if ((strlen (EGO_NAMESPACE) < strlen (url)) &&
-       (url[strlen (EGO_NAMESPACE)] != '/'))
-  {
-    return GNUNET_NO;
-  }
-  return GNUNET_YES;
-
-
-}
-
-/**
  * Create a response with requested ego(s)
  *
  * @param handle the RequestHandle
@@ -339,18 +294,19 @@ ego_info_response (struct RequestHandle *handle)
   struct EgoEntry *ego_entry;
   struct GNUNET_HashCode key;
   struct MHD_Response *resp;
-  json_t *ego_arr;
-  json_t *ego_json;
-  json_t *root_json;
+  struct JsonApiResponse *json_response;
+  struct JsonApiResource *json_resource;
+  json_t *key_str;
 
-  if (GNUNET_NO == check_namespace (handle->url, EGO_NAMESPACE))
+  if (GNUNET_NO == GNUNET_REST_namespace_match (handle->url, EGO_NAMESPACE))
   {
-    resp = create_json_response (NULL);
+    resp = GNUNET_REST_create_json_response (NULL);
     handle->proc (handle->proc_cls, resp, MHD_HTTP_BAD_REQUEST);
     cleanup_handle (handle);
     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 ==
@@ -371,8 +327,7 @@ ego_info_response (struct RequestHandle *handle)
       }
     }
   }
-  ego_arr = json_array ();
-  root_json = json_object ();
+  json_response = GNUNET_REST_jsonapi_response_new ();
   egoname = &handle->url[strlen (EGO_NAMESPACE)+1];
 
   if (strlen (EGO_NAMESPACE) == strlen (handle->url))
@@ -387,36 +342,24 @@ ego_info_response (struct RequestHandle *handle)
   {
     if ( (NULL != egoname) && (0 != strcmp (egoname, ego_entry->identifier)) )
       continue;
-    ego_json = json_object ();
     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, "key", json_string (keystring));
-    json_object_set_new (ego_json, "type", json_string (JSON_API_TYPE_EGO));
+    json_resource = GNUNET_REST_jsonapi_resource_new (GNUNET_REST_JSONAPI_IDENTITY_EGO, ego_entry->identifier);
+    key_str = json_string (keystring);
+    GNUNET_REST_jsonapi_resource_add_attr (json_resource,
+                                           GNUNET_REST_JSONAPI_IDENTITY_KEY,
+                                           key_str);
+    json_decref (key_str);
     GNUNET_free (keystring);
-    if (NULL == egoname)
-    {
-      json_array_append (ego_arr, ego_json);
-      json_decref (ego_json);
-    }
-    else
-      break;
+    GNUNET_REST_jsonapi_response_resource_add (json_response, json_resource);
   }
-  if (NULL == egoname)
-    json_object_set (root_json, "egos", ego_arr);
-  else
-    json_object_set (root_json, "ego", ego_json);
 
-  result_str = json_dumps (root_json, JSON_COMPACT);
-  json_decref (ego_arr);
-  if (NULL != egoname)
-    json_decref (ego_json);
+  GNUNET_REST_jsonapi_data_serialize (json_response, &result_str);
 
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Result %s\n", result_str);
-  resp = create_json_response (result_str);
+  resp = GNUNET_REST_create_json_response (result_str);
   handle->proc (handle->proc_cls, resp, MHD_HTTP_OK);
   GNUNET_free (result_str);
   cleanup_handle (handle);
-
 }
 
 static void
@@ -431,7 +374,7 @@ do_finished (void *cls, const char *emsg)
     GNUNET_SCHEDULER_add_now (&do_error, handle);
     return;
   }
-  resp = create_json_response (NULL);
+  resp = GNUNET_REST_create_json_response (NULL);
   handle->proc (handle->proc_cls, resp, MHD_HTTP_NO_CONTENT);
   cleanup_handle (handle);
 }
@@ -448,7 +391,7 @@ set_finished (void *cls, const char *emsg)
     GNUNET_SCHEDULER_add_now (&do_error, handle);
     return;
   }
-  resp = create_json_response (NULL);
+  resp = GNUNET_REST_create_json_response (NULL);
   handle->proc (handle->proc_cls, resp, MHD_HTTP_NO_CONTENT);
   cleanup_handle (handle);
 }
@@ -465,7 +408,7 @@ create_finished (void *cls, const char *emsg)
     GNUNET_SCHEDULER_add_now (&do_error, handle);
     return;
   }
-  resp = create_json_response (NULL);
+  resp = GNUNET_REST_create_json_response (NULL);
   handle->proc (handle->proc_cls, resp, MHD_HTTP_NO_CONTENT);
   cleanup_handle (handle);
 }
@@ -503,7 +446,7 @@ ego_create_cont (struct RequestHandle *handle)
     GNUNET_SCHEDULER_add_now (&do_error, handle);
     return;
   }
-  data_json = json_object_get (root_json, JSON_API_TYPE_DATA);
+  data_json = json_object_get (root_json, GNUNET_REST_JSONAPI_KEY_DATA);
   if ((NULL == data_json) || !json_is_object (data_json))
   {
     GNUNET_SCHEDULER_add_now (&do_error, handle);
@@ -511,11 +454,11 @@ ego_create_cont (struct RequestHandle *handle)
   }
   type_json = json_object_get (data_json, "type");
   if (!json_is_string (type_json) ||
-      (0 != strcmp (JSON_API_TYPE_EGO, json_string_value (type_json))))
+      (0 != strcmp (GNUNET_REST_JSONAPI_IDENTITY_EGO, json_string_value (type_json))))
   {
     json_decref (data_json);
     json_decref (root_json);
-    resp = create_json_response (NULL);
+    resp = GNUNET_REST_create_json_response (NULL);
     handle->proc (handle->proc_cls, resp, MHD_HTTP_CONFLICT);
     cleanup_handle (handle);
     return;
@@ -540,7 +483,7 @@ ego_create_cont (struct RequestHandle *handle)
       json_decref (egoname_json);
       json_decref (data_json);
       json_decref (root_json);
-      resp = create_json_response (NULL);
+      resp = GNUNET_REST_create_json_response (NULL);
       handle->proc (handle->proc_cls, resp, MHD_HTTP_CONFLICT);
       cleanup_handle (handle);
       return;
@@ -591,7 +534,7 @@ subsys_set_cont (struct RequestHandle *handle)
   }
   if (GNUNET_NO == ego_exists)
   {
-    resp = create_json_response (NULL);
+    resp = GNUNET_REST_create_json_response (NULL);
     handle->proc (handle->proc_cls, resp, MHD_HTTP_NOT_FOUND);
     cleanup_handle (handle);
     return;
@@ -632,7 +575,7 @@ subsys_set_cont (struct RequestHandle *handle)
 
   type_json = json_object_get (data_json, "type");
   if (!json_is_string (type_json) ||
-      (0 != strcmp (JSON_API_TYPE_EGO, json_string_value (type_json))))
+      (0 != strcmp (GNUNET_REST_JSONAPI_IDENTITY_EGO, json_string_value (type_json))))
   {
     json_decref (root_json);
     json_decref (data_json);
@@ -687,7 +630,7 @@ ego_delete_cont (struct RequestHandle *handle)
   }
   if (GNUNET_NO == ego_exists)
   {
-    resp = create_json_response (NULL);
+    resp = GNUNET_REST_create_json_response (NULL);
     handle->proc (handle->proc_cls, resp, MHD_HTTP_NOT_FOUND);
     cleanup_handle (handle);
     return;
diff --git a/src/include/gnunet_rest_lib.h b/src/include/gnunet_rest_lib.h
new file mode 100644
index 000000000..19a0168e5
--- /dev/null
+++ b/src/include/gnunet_rest_lib.h
@@ -0,0 +1,156 @@
+/*
+      This file is part of GNUnet
+      Copyright (C) 2010-2015 Christian Grothoff (and other contributing authors)
+
+      GNUnet is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published
+      by the Free Software Foundation; either version 3, or (at your
+      option) any later version.
+
+      GNUnet is distributed in the hope that it will be useful, but
+      WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+      General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with GNUnet; see the file COPYING.  If not, write to the
+      Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+      Boston, MA 02111-1307, USA.
+ */
+
+/**
+ * @file include/gnunet_rest_lib.h
+ * @brief API for helper library to parse/create REST
+ * @author Martin Schanzenbach
+ */
+#ifndef GNUNET_REST_LIB_H
+#define GNUNET_REST_LIB_H
+
+#include "gnunet_util_lib.h"
+#include "microhttpd.h"
+#include <jansson.h>
+
+#define GNUNET_REST_JSONAPI_KEY_DATA "data"
+
+#define GNUNET_REST_JSONAPI_KEY_ID "id"
+
+#define GNUNET_REST_JSONAPI_KEY_TYPE "type"
+
+/**
+ * Resource structs for JSON API
+ */
+struct JsonApiResource;
+
+/**
+ * Responses for JSON API
+ */
+struct JsonApiResponse;
+
+/**
+ * Create a JSON API resource
+ *
+ * @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 JsonApiResource*
+GNUNET_REST_jsonapi_resource_new (const char *type, const char *id);
+
+/**
+ * Delete a JSON API resource
+ *
+ * @param res the JSON resource
+ * @param result Pointer where the resource should be stored
+ */
+void
+GNUNET_REST_jsonapi_resource_delete (struct JsonApiResource *resource);
+
+/**
+ * Add a JSON API attribute
+ *
+ * @param res the JSON resource
+ * @param key the key for the attribute
+ * @param json the json_t attribute to add
+ * @return #GNUNET_OK if added successfully
+ *         #GNUNET_SYSERR if not
+ */
+int
+GNUNET_REST_jsonapi_resource_add_attr (const struct JsonApiResource *resource,
+                                       const char* key,
+                                       json_t *json);
+
+/**
+ * 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 ();
+
+/**
+ * Delete 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.
+ */
+void
+GNUNET_REST_jsonapi_response_delete (struct JsonApiResponse *resp);
+
+/**
+ * Add a JSON API resource 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,
+                                           struct JsonApiResource *res);
+
+/**
+ * Add a JSON API resource to primary data
+ *
+ * @param resp 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_data_resource_remove (struct JsonApiResponse *resp,
+                                          struct JsonApiResource *res);
+
+/**
+ * String serialze jsonapi primary data
+ *
+ * @param data the JSON API primary data
+ * @param result where to store the result
+ * @return GNUNET_SYSERR on error else GNUNET_OK
+ */
+int
+GNUNET_REST_jsonapi_data_serialize (const struct JsonApiResponse *resp,
+                                    char **result);
+
+/**
+ * Check if namespace is in URL.
+ *
+ * @param url URL to check
+ * @param namespace namespace to check against
+ * @retun GNUNET_YES if namespace matches
+ */
+int
+GNUNET_REST_namespace_match (const char *url, const char *namespace);
+
+/**
+ * Create JSON API MHD response
+ *
+ * @param data JSON result
+ * @retun MHD response
+ */
+ struct MHD_Response*
+GNUNET_REST_create_json_response (const char *data);
+
+
+
+#endif
diff --git a/src/include/gnunet_rest_plugin.h b/src/include/gnunet_rest_plugin.h
index 1d5a2db59..e085ccf32 100644
--- a/src/include/gnunet_rest_plugin.h
+++ b/src/include/gnunet_rest_plugin.h
@@ -37,6 +37,7 @@ extern "C"
 #endif
 #endif
 
+
 /**
  * Iterator called on obtained result for a REST result.
  *
diff --git a/src/rest/Makefile.am b/src/rest/Makefile.am
index 00021cce2..8ea87fc6a 100644
--- a/src/rest/Makefile.am
+++ b/src/rest/Makefile.am
@@ -20,6 +20,9 @@ if USE_COVERAGE
   XLIBS = -lgcov
 endif
 
+lib_LTLIBRARIES = \
+        libgnunetrest.la
+
 libexec_PROGRAMS = \
  gnunet-rest-server
 
@@ -29,3 +32,12 @@ gnunet_rest_server_SOURCES = \
 gnunet_rest_server_LDADD = \
   $(top_builddir)/src/util/libgnunetutil.la \
   $(GN_LIBINTL) -lmicrohttpd
+
+libgnunetrest_la_SOURCES = \
+  rest.c
+libgnunetrest_la_LIBADD = \
+  $(top_builddir)/src/util/libgnunetutil.la $(XLIB) \
+  $(GN_LIBINTL) -lmicrohttpd -ljansson
+libgnunetrest_la_LDFLAGS = \
+  $(GN_LIB_LDFLAGS) \
+  -version-info 0:0:0
diff --git a/src/rest/rest.c b/src/rest/rest.c
new file mode 100644
index 000000000..0b843ec61
--- /dev/null
+++ b/src/rest/rest.c
@@ -0,0 +1,299 @@
+/*
+      This file is part of GNUnet
+      Copyright (C) 2010-2015 Christian Grothoff (and other contributing authors)
+
+      GNUnet is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published
+      by the Free Software Foundation; either version 3, or (at your
+      option) any later version.
+
+      GNUnet is distributed in the hope that it will be useful, but
+      WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+      General Public License for more details.
+
+      You should have received a copy of the GNU General Public License
+      along with GNUnet; see the file COPYING.  If not, write to the
+      Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+      Boston, MA 02111-1307, USA.
+ */
+
+/**
+ * @file rest/rest.c
+ * @brief helper library to create JSON REST Objects and handle REST
+ * responses/requests.
+ * @author Martin Schanzenbach
+ */
+#include "platform.h"
+#include "gnunet_util_lib.h"
+#include "gnunet_rest_lib.h"
+#include "microhttpd.h"
+#include <jansson.h>
+
+
+struct JsonApiResource
+{
+  /**
+   * DLL
+   */
+  struct JsonApiResource *next;
+
+  /**
+   * DLL
+   */
+  struct JsonApiResource *prev;
+
+  /**
+   * Resource content
+   */
+  json_t *res_obj;
+};
+
+
+struct JsonApiResponse
+{
+  /**
+   * DLL Resource
+   */
+  struct JsonApiResource *res_list_head;
+
+  /**
+   * DLL Resource
+   */
+  struct JsonApiResource *res_list_tail;
+
+  /**
+   * num resources
+   */
+  int res_count;
+};
+
+/**
+ * JSON API
+ */
+
+/**
+ * Create a JSON API resource
+ *
+ * @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 JsonApiResource*
+GNUNET_REST_jsonapi_resource_new (const char *type, const char *id)
+{
+  struct JsonApiResource *res;
+
+  if ( (NULL == type) || (0 == strlen (type)) )
+    return NULL;
+  if ( (NULL == id) || (0 == strlen (id)) )
+    return NULL;
+
+  res = GNUNET_new (struct JsonApiResource);
+  
+  res->res_obj = json_object ();
+
+  json_object_set_new (res->res_obj, GNUNET_REST_JSONAPI_KEY_ID, json_string (id));
+  json_object_set_new (res->res_obj, GNUNET_REST_JSONAPI_KEY_TYPE, json_string (type));
+
+  return res;
+}
+
+/**
+ * Delete a JSON API resource
+ *
+ * @param res the JSON resource
+ * @param result Pointer where the resource should be stored
+ */
+void
+GNUNET_REST_jsonapi_resource_delete (struct JsonApiResource *resource)
+{
+  json_decref (resource->res_obj);
+  GNUNET_free (resource);
+}
+
+/**
+ * Add a JSON API attribute
+ *
+ * @param res the JSON resource
+ * @param key the key for the attribute
+ * @param json the json_t attribute to add
+ * @return #GNUNET_OK if added successfully
+ *         #GNUNET_SYSERR if not
+ */
+int
+GNUNET_REST_jsonapi_resource_add_attr (const struct JsonApiResource *resource,
+                                       const char* key,
+                                       json_t *json)
+{
+  if ( (NULL == resource) ||
+       (NULL == key) ||
+       (NULL == json) )
+    return GNUNET_SYSERR;
+  json_object_set (resource->res_obj, key, json);
+  return GNUNET_OK;
+}
+
+
+
+
+/**
+ * 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 JsonApiResponse *result;
+
+  result = GNUNET_new (struct JsonApiResponse);
+  result->res_count = 0;
+  return result;
+}
+
+/**
+ * Delete 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.
+ */
+void
+GNUNET_REST_jsonapi_response_delete (struct JsonApiResponse *resp)
+{
+  struct JsonApiResource *res;
+  
+  for (res = resp->res_list_head; 
+       res != NULL;
+       res = res->next)
+    GNUNET_REST_jsonapi_resource_delete (res);
+  GNUNET_free (resp);
+}
+
+/**
+ * Add a JSON API resource 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,
+                                           struct JsonApiResource *res)
+{
+  GNUNET_CONTAINER_DLL_insert (resp->res_list_head,
+                            resp->res_list_tail,
+                            res);
+  
+  resp->res_count++;
+}
+
+/**
+ * Add a JSON API resource 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_data_resource_remove (struct JsonApiResponse *resp,
+                                          struct JsonApiResource *res)
+{
+  GNUNET_CONTAINER_DLL_remove (resp->res_list_head,
+                               resp->res_list_tail,
+                              res);
+  resp->res_count--;
+}
+
+/**
+ * String serialze jsonapi primary data
+ *
+ * @param data the JSON API primary data
+ * @param result where to store the result
+ * @return GNUNET_SYSERR on error else GNUNET_OK
+ */
+int
+GNUNET_REST_jsonapi_data_serialize (const struct JsonApiResponse *resp,
+                                    char **result)
+{
+  struct JsonApiResource *res;
+  json_t *root_json;
+  json_t *res_arr;
+  
+  if ( (NULL == resp) ||
+       (0 == resp->res_count) )
+    return GNUNET_SYSERR;
+
+  root_json = json_object ();
+  
+  if (1 == resp->res_count)
+  {
+    json_object_set (root_json, GNUNET_REST_JSONAPI_KEY_DATA, resp->res_list_head->res_obj);
+  }
+  else
+  {
+    res_arr = json_array ();
+    for (res = resp->res_list_head; 
+         res != NULL;
+         res = res->next)
+    {
+      json_array_append (res_arr, res->res_obj);
+    }
+    json_object_set (root_json, GNUNET_REST_JSONAPI_KEY_DATA, res_arr);
+  }
+  *result = json_dumps (root_json, JSON_COMPACT);
+  return GNUNET_OK;
+}
+
+/**
+ * REST Utilities
+ */
+
+/**
+ * Check if namespace is in URL.
+ *
+ * @param url URL to check
+ * @param namespace namespace to check against
+ * @retun GNUNET_YES if namespace matches
+ */
+int
+GNUNET_REST_namespace_match (const char *url, const char *namespace)
+{
+  if (0 != strncmp (namespace, url, strlen (namespace)))
+    return GNUNET_NO;
+
+  if ((strlen (namespace) < strlen (url)) &&
+      (url[strlen (namespace)] != '/'))
+    return GNUNET_NO;
+
+  return GNUNET_YES;
+}
+
+/**
+ * Create JSON API MHD response
+ *
+ * @param data JSON result
+ * @retun MHD response
+ */
+ struct MHD_Response*
+GNUNET_REST_create_json_response (const char *data)
+{
+  struct MHD_Response *resp;
+  size_t len;
+
+  if (NULL == data)
+    len = 0;
+  else
+    len = strlen (data);
+  resp = MHD_create_response_from_buffer (len,
+                                          (void*)data,
+                                          MHD_RESPMEM_MUST_COPY);
+  MHD_add_response_header (resp,MHD_HTTP_HEADER_CONTENT_TYPE,"application/json");
+  return resp;
+
+}
+
+/* end of rest.c */