plugin_rest_gns.c

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/*
   This file is part of GNUnet.
   Copyright (C) 2012-2015 GNUnet e.V.

   GNUnet is free software: you can redistribute it and/or modify it
   under the terms of the GNU Affero General Public License as published
   by the Free Software Foundation, either version 3 of the License,
   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
   Affero General Public License for more details.

   You should have received a copy of the GNU Affero General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.

     SPDX-License-Identifier: AGPL3.0-or-later
 */
#include "platform.h"
#include "gnunet_rest_plugin.h"
#include "gnunet_rest_lib.h"
#include "gnunet_json_lib.h"
#include "gnunet_gnsrecord_lib.h"
#include "gnunet_gns_service.h"
#include "microhttpd.h"
#include <jansson.h>

#define GNUNET_REST_API_NS_GNS "/gns"

#define GNUNET_REST_GNS_PARAM_RECORD_TYPE "record_type"

#define GNUNET_REST_GNS_ERROR_UNKNOWN "Unknown Error"

#define GNUNET_REST_GNS_NOT_FOUND "Record not found"

const struct GNUNET_CONFIGURATION_Handle *cfg;

static char *allow_methods;

struct Plugin {
  const struct GNUNET_CONFIGURATION_Handle *cfg;
};

struct RequestHandle {
  struct GNUNET_GNS_Handle *gns;

  struct GNUNET_GNS_LookupWithTldRequest *gns_lookup;

  char *name;

  int record_type;

  struct GNUNET_REST_RequestHandle *rest_handle;

  struct GNUNET_TIME_Relative timeout;

  struct GNUNET_SCHEDULER_Task *timeout_task;

  GNUNET_REST_ResultProcessor proc;

  void *proc_cls;

  char *url;

  char *emsg;

  int response_code;
};


static void
cleanup_handle(void *cls)
{
  struct RequestHandle *handle = cls;

  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Cleaning up\n");

  if (NULL != handle->gns_lookup)
    {
      GNUNET_GNS_lookup_with_tld_cancel(handle->gns_lookup);
      handle->gns_lookup = NULL;
    }
  if (NULL != handle->gns)
    {
      GNUNET_GNS_disconnect(handle->gns);
      handle->gns = NULL;
    }

  if (NULL != handle->timeout_task)
    {
      GNUNET_SCHEDULER_cancel(handle->timeout_task);
      handle->timeout_task = NULL;
    }
  if (NULL != handle->url)
    GNUNET_free(handle->url);
  if (NULL != handle->name)
    GNUNET_free(handle->name);
  if (NULL != handle->emsg)
    GNUNET_free(handle->emsg);

  GNUNET_free(handle);
}


static void
do_error(void *cls)
{
  struct RequestHandle *handle = cls;
  struct MHD_Response *resp;
  json_t *json_error = json_object();
  char *response;

  if (NULL != handle->timeout_task)
    GNUNET_SCHEDULER_cancel(handle->timeout_task);
  handle->timeout_task = NULL;
  if (NULL == handle->emsg)
    handle->emsg = GNUNET_strdup(GNUNET_REST_GNS_ERROR_UNKNOWN);

  json_object_set_new(json_error, "error", json_string(handle->emsg));

  if (0 == handle->response_code)
    handle->response_code = MHD_HTTP_INTERNAL_SERVER_ERROR;
  response = json_dumps(json_error, 0);
  resp = GNUNET_REST_create_response(response);
  handle->proc(handle->proc_cls, resp, handle->response_code);
  json_decref(json_error);
  GNUNET_free(response);
  GNUNET_SCHEDULER_add_now(&cleanup_handle, handle);
}


static void
do_timeout(void *cls)
{
  struct RequestHandle *handle = cls;

  handle->timeout_task = NULL;
  handle->response_code = MHD_HTTP_REQUEST_TIMEOUT;
  do_error(handle);
}


static void
handle_gns_response(void *cls,
                    int was_gns,
                    uint32_t rd_count,
                    const struct GNUNET_GNSRECORD_Data *rd)
{
  struct RequestHandle *handle = cls;
  struct MHD_Response *resp;
  json_t *result_obj;
  char *result;

  handle->gns_lookup = NULL;

  if (GNUNET_NO == was_gns)
    {
      handle->response_code = MHD_HTTP_NOT_FOUND;
      handle->emsg = GNUNET_strdup(GNUNET_REST_GNS_NOT_FOUND);
      GNUNET_SCHEDULER_add_now(&do_error, handle);
      return;
    }

  result_obj = GNUNET_JSON_from_gnsrecord(handle->name, rd, rd_count);

  result = json_dumps(result_obj, 0);
  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Result %s\n", result);
  resp = GNUNET_REST_create_response(result);
  handle->proc(handle->proc_cls, resp, MHD_HTTP_OK);
  GNUNET_free(result);
  json_decref(result_obj);
  GNUNET_SCHEDULER_add_now(&cleanup_handle, handle);
}


void
get_gns_cont(struct GNUNET_REST_RequestHandle *con_handle,
             const char *url,
             void *cls)
{
  struct RequestHandle *handle = cls;
  struct GNUNET_HashCode key;
  char *record_type;
  char *name;

  name = NULL;
  handle->name = NULL;
  if (strlen(GNUNET_REST_API_NS_GNS) < strlen(handle->url))
    {
      name = &handle->url[strlen(GNUNET_REST_API_NS_GNS) + 1];
    }

  if (NULL == name)
    {
      handle->response_code = MHD_HTTP_NOT_FOUND;
      handle->emsg = GNUNET_strdup(GNUNET_REST_GNS_NOT_FOUND);
      GNUNET_SCHEDULER_add_now(&do_error, handle);
      return;
    }
  if (0 >= strlen(name))
    {
      handle->response_code = MHD_HTTP_NOT_FOUND;
      handle->emsg = GNUNET_strdup(GNUNET_REST_GNS_NOT_FOUND);
      GNUNET_SCHEDULER_add_now(&do_error, handle);
      return;
    }
  handle->name = GNUNET_strdup(name);

  handle->record_type = UINT32_MAX;
  GNUNET_CRYPTO_hash(GNUNET_REST_GNS_PARAM_RECORD_TYPE,
                     strlen(GNUNET_REST_GNS_PARAM_RECORD_TYPE),
                     &key);
  if (GNUNET_YES ==
      GNUNET_CONTAINER_multihashmap_contains(con_handle->url_param_map, &key))
    {
      record_type =
        GNUNET_CONTAINER_multihashmap_get(con_handle->url_param_map, &key);
      handle->record_type = GNUNET_GNSRECORD_typename_to_number(record_type);
    }

  if (UINT32_MAX == handle->record_type)
    {
      handle->record_type = GNUNET_GNSRECORD_TYPE_ANY;
    }

  handle->gns_lookup = GNUNET_GNS_lookup_with_tld(handle->gns,
                                                  handle->name,
                                                  handle->record_type,
                                                  GNUNET_NO,
                                                  &handle_gns_response,
                                                  handle);
}


static void
options_cont(struct GNUNET_REST_RequestHandle *con_handle,
             const char *url,
             void *cls)
{
  struct MHD_Response *resp;
  struct RequestHandle *handle = cls;

  //independent of path return all options
  resp = GNUNET_REST_create_response(NULL);
  MHD_add_response_header(resp, "Access-Control-Allow-Methods", allow_methods);
  handle->proc(handle->proc_cls, resp, MHD_HTTP_OK);
  GNUNET_SCHEDULER_add_now(&cleanup_handle, handle);
  return;
}


static void
init_cont(struct RequestHandle *handle)
{
  struct GNUNET_REST_RequestHandlerError err;
  static const struct GNUNET_REST_RequestHandler handlers[] =
  { { MHD_HTTP_METHOD_GET, GNUNET_REST_API_NS_GNS, &get_gns_cont },
    { MHD_HTTP_METHOD_OPTIONS, GNUNET_REST_API_NS_GNS, &options_cont },
    GNUNET_REST_HANDLER_END };

  if (GNUNET_NO ==
      GNUNET_REST_handle_request(handle->rest_handle, handlers, &err, handle))
    {
      handle->response_code = err.error_code;
      GNUNET_SCHEDULER_add_now(&do_error, handle);
    }
}


static void
rest_process_request(struct GNUNET_REST_RequestHandle *rest_handle,
                     GNUNET_REST_ResultProcessor proc,
                     void *proc_cls)
{
  struct RequestHandle *handle = GNUNET_new(struct RequestHandle);

  handle->response_code = 0;
  handle->timeout =
    GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_SECONDS, 60);
  handle->proc_cls = proc_cls;
  handle->proc = proc;
  handle->rest_handle = rest_handle;

  handle->url = GNUNET_strdup(rest_handle->url);
  if (handle->url[strlen(handle->url) - 1] == '/')
    handle->url[strlen(handle->url) - 1] = '\0';
  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Connecting...\n");
  handle->gns = GNUNET_GNS_connect(cfg);
  init_cont(handle);

  handle->timeout_task =
    GNUNET_SCHEDULER_add_delayed(handle->timeout, &do_timeout, handle);

  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Connected\n");
}


void *
libgnunet_plugin_rest_gns_init(void *cls)
{
  static struct Plugin plugin;
  struct GNUNET_REST_Plugin *api;

  cfg = cls;
  if (NULL != plugin.cfg)
    return NULL; /* can only initialize once! */
  memset(&plugin, 0, sizeof(struct Plugin));
  plugin.cfg = cfg;
  api = GNUNET_new(struct GNUNET_REST_Plugin);
  api->cls = &plugin;
  api->name = GNUNET_REST_API_NS_GNS;
  api->process_request = &rest_process_request;
  GNUNET_asprintf(&allow_methods,
                  "%s, %s, %s, %s, %s",
                  MHD_HTTP_METHOD_GET,
                  MHD_HTTP_METHOD_POST,
                  MHD_HTTP_METHOD_PUT,
                  MHD_HTTP_METHOD_DELETE,
                  MHD_HTTP_METHOD_OPTIONS);

  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, _("Gns REST API initialized\n"));
  return api;
}


void *
libgnunet_plugin_rest_gns_done(void *cls)
{
  struct GNUNET_REST_Plugin *api = cls;
  struct Plugin *plugin = api->cls;

  plugin->cfg = NULL;

  GNUNET_free_non_null(allow_methods);
  GNUNET_free(api);
  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Gns REST plugin is finished\n");
  return NULL;
}

/* end of plugin_rest_gns.c */