post_example.c

/*
 * Copyright (c) 2021 nliviu
 * All rights reserved
 *
 * Licensed under the Apache License, Version 2.0 (the ""License"");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an ""AS IS"" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "mgos.h"

/*
 * https://reqres.in/
 */

struct request {
  const char *api;
  const char *payload;
};

static const char *s_host = "reqres.in";
static const char *s_uri = "/api/";
static struct mg_connection *s_http_connection = NULL;

static struct request requests[] = {
    /* success */
    {"register", "{\"email\": \"eve.holt@reqres.in\", \"password\": \"123\"}"},
    /* fail */
    {"register", "{\"email\": \"eve.holt@fife.com\"}"},
    /* fail */
    {"login", "{\"email\": \"eve.holt@reqres.in\"}"},
    /* success */
    {"login", "{\"email\": \"eve.holt@reqres.in\", \"password\": \"123\"}"},
};

static const size_t requests_count = sizeof(requests) / sizeof(requests[0]);

static void ev_handler(struct mg_connection *c, int ev, void *ev_data,
                       void *user_data) {
  switch (ev) {
    case MG_EV_CONNECT: {
      int status = *(int *) ev_data;
      if (status != 0) {
        mg_http_send_error(c, 502, "Error!");
        LOG(LL_INFO, ("%.3lf - connect error %d (%s)", mgos_uptime(), status,
                      strerror(status)));
      } else {
        LOG(LL_INFO,
            ("%.3lf - connected OK (mg_connection %p)", mgos_uptime(), c));
      }
      break;
    }
    case MG_EV_HTTP_REPLY: {
      struct http_message *hm = (struct http_message *) ev_data;
      LOG(LL_INFO, ("%.3lf - Reply: %.*s", mgos_uptime(), (int) hm->body.len,
                    hm->body.p));
      break;
    }
    case MG_EV_CLOSE: {
      LOG(LL_INFO, ("%.3lf - mg_connection %p closed", mgos_uptime(), c));
      s_http_connection = NULL;
      break;
    }
  }

  (void) user_data;
}

static void send_request(size_t index) {
  const char *extra_headers =
      "Content-Type: application/json\r\n"
      "Accept: application/json\r\n";

  const char *payload = requests[index].payload;
  if (s_http_connection == NULL) {
    char url_buf[64];
    char *url = url_buf;
    mg_asprintf(&url, sizeof(url_buf), "https://%s%s%s", s_host, s_uri,
                requests[index].api);
    LOG(LL_INFO, ("%.3lf - Request (new connection): url=%s, payload=%s",
                  mgos_uptime(), url, requests[index].payload));
    s_http_connection = mg_connect_http(mgos_get_mgr(), ev_handler, NULL, url,
                                        extra_headers, payload);
    if (url != url_buf) {
      free(url);
    }
  } else {
    int payload_len = strlen(payload);
    const char *fmt =
        "POST %s HTTP/1.1\r\nHost: %s\r\nContent-Length: %d\r\n%s\r\n%s";
    char uri[32];
    snprintf(uri, sizeof(uri), "%s%s", s_uri, requests[index].api);
    LOG(LL_INFO,
        ("%.3lf - Request (reusing connection): host: %s, uri: %s, payload: %s",
         mgos_uptime(), s_host, uri, payload));
    mg_printf(s_http_connection, fmt, uri, s_host, payload_len, extra_headers,
              payload);
  }
}

static void timer_cb(void *arg) {
  static size_t index = 0;
  send_request(index);
  ++index;
  if (index >= requests_count) {
    index = 0;
  }
  (void) arg;
}

static void net_event_handler(int ev, void *evd, void *arg) {
  static bool init = false;
  if (ev == MGOS_NET_EV_IP_ACQUIRED) {
    if (!init) {
      init = true;
      mgos_set_timer(15000, MGOS_TIMER_REPEAT | MGOS_TIMER_RUN_NOW, timer_cb,
                     NULL);
    }
  }

  (void) evd;
  (void) arg;
}

enum mgos_app_init_result mgos_app_init(void) {
  mgos_event_add_group_handler(MGOS_EVENT_GRP_NET, net_event_handler, NULL);
  return MGOS_APP_INIT_SUCCESS;
}