text: /* ESP HTTP Client Example
  
     This example code is in the Public Domain (or CC0 licensed, at your option.)
  
     Unless required by applicable law or agreed to in writing, this
     software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
     CONDITIONS OF ANY KIND, either express or implied.
  */
  
  #include <string.h>
  #include <stdlib.h>
  #include "freertos/FreeRTOS.h"
  #include "freertos/task.h"
  #include "esp_log.h"
  #include "esp_system.h"
  #include "nvs_flash.h"
  #include "app_wifi.h"
  
  #include "esp_http_client.h"
  
  #define MAX_HTTP_RECV_BUFFER 512
  static const char *TAG = "HTTP_CLIENT";
  
  /* Root cert for howsmyssl.com, taken from howsmyssl_com_root_cert.pem
  
     The PEM file was extracted from the output of this command:
     openssl s_client -showcerts -connect www.howsmyssl.com:443 </dev/null
  
     The CA root cert is the last cert given in the chain of certs.
  
     To embed it in the app binary, the PEM file is named
     in the component.mk COMPONENT_EMBED_TXTFILES variable.
  */
  extern const char howsmyssl_com_root_cert_pem_start[] asm("_binary_howsmyssl_com_root_cert_pem_start");
  extern const char howsmyssl_com_root_cert_pem_end[]   asm("_binary_howsmyssl_com_root_cert_pem_end");
  
  esp_err_t _http_event_handler(esp_http_client_event_t *evt)
  {
      switch(evt->event_id) {
          case HTTP_EVENT_ERROR:
              ESP_LOGD(TAG, "HTTP_EVENT_ERROR");
              break;
          case HTTP_EVENT_ON_CONNECTED:
              ESP_LOGD(TAG, "HTTP_EVENT_ON_CONNECTED");
              break;
          case HTTP_EVENT_HEADER_SENT:
              ESP_LOGD(TAG, "HTTP_EVENT_HEADER_SENT");
              break;
          case HTTP_EVENT_ON_HEADER:
              ESP_LOGD(TAG, "HTTP_EVENT_ON_HEADER, key=%s, value=%s", evt->header_key, evt->header_value);
              break;
          case HTTP_EVENT_ON_DATA:
              ESP_LOGD(TAG, "HTTP_EVENT_ON_DATA, len=%d", evt->data_len);
              if (!esp_http_client_is_chunked_response(evt->client)) {
                  // Write out data
                  // printf("%.*s", evt->data_len, (char*)evt->data);
              }
  
              break;
          case HTTP_EVENT_ON_FINISH:
              ESP_LOGD(TAG, "HTTP_EVENT_ON_FINISH");
              break;
          case HTTP_EVENT_DISCONNECTED:
              ESP_LOGD(TAG, "HTTP_EVENT_DISCONNECTED");
              break;
      }
      return ESP_OK;
  }
  
  static void http_rest()
  {
      esp_http_client_config_t config = {
          .url = "http://httpbin.org/get",
          .event_handler = _http_event_handler,
      };
      esp_http_client_handle_t client = esp_http_client_init(&config);
  
      // GET
      esp_err_t err = esp_http_client_perform(client);
      if (err == ESP_OK) {
          ESP_LOGI(TAG, "HTTP GET Status = %d, content_length = %d",
                  esp_http_client_get_status_code(client),
                  esp_http_client_get_content_length(client));
      } else {
          ESP_LOGE(TAG, "HTTP GET request failed: %s", esp_err_to_name(err));
      }
  
      // POST
      const char *post_data = "field1=value1&field2=value2";
      esp_http_client_set_url(client, "http://httpbin.org/post");
      esp_http_client_set_method(client, HTTP_METHOD_POST);
      esp_http_client_set_post_field(client, post_data, strlen(post_data));
      err = esp_http_client_perform(client);
      if (err == ESP_OK) {
          ESP_LOGI(TAG, "HTTP POST Status = %d, content_length = %d",
                  esp_http_client_get_status_code(client),
                  esp_http_client_get_content_length(client));
      } else {
          ESP_LOGE(TAG, "HTTP POST request failed: %s", esp_err_to_name(err));
      }
  
      //PUT
      esp_http_client_set_url(client, "http://httpbin.org/put");
      esp_http_client_set_method(client, HTTP_METHOD_PUT);
      err = esp_http_client_perform(client);
      if (err == ESP_OK) {
          ESP_LOGI(TAG, "HTTP PUT Status = %d, content_length = %d",
                  esp_http_client_get_status_code(client),
                  esp_http_client_get_content_length(client));
      } else {
          ESP_LOGE(TAG, "HTTP PUT request failed: %s", esp_err_to_name(err));
      }
  
      //PATCH
      esp_http_client_set_url(client, "http://httpbin.org/patch");
      esp_http_client_set_method(client, HTTP_METHOD_PATCH);
      esp_http_client_set_post_field(client, NULL, 0);
      err = esp_http_client_perform(client);
      if (err == ESP_OK) {
          ESP_LOGI(TAG, "HTTP PATCH Status = %d, content_length = %d",
                  esp_http_client_get_status_code(client),
                  esp_http_client_get_content_length(client));
      } else {
          ESP_LOGE(TAG, "HTTP PATCH request failed: %s", esp_err_to_name(err));
      }
  
      //DELETE
      esp_http_client_set_url(client, "http://httpbin.org/delete");
      esp_http_client_set_method(client, HTTP_METHOD_DELETE);
      err = esp_http_client_perform(client);
      if (err == ESP_OK) {
          ESP_LOGI(TAG, "HTTP DELETE Status = %d, content_length = %d",
                  esp_http_client_get_status_code(client),
                  esp_http_client_get_content_length(client));
      } else {
          ESP_LOGE(TAG, "HTTP DELETE request failed: %s", esp_err_to_name(err));
      }
  
      esp_http_client_cleanup(client);
  }
  
  static void http_auth_basic()
  {
      esp_http_client_config_t config = {
          .url = "http://user:passwd@httpbin.org/basic-auth/user/passwd",
          .event_handler = _http_event_handler,
          .auth_type = HTTP_AUTH_TYPE_BASIC,
      };
      esp_http_client_handle_t client = esp_http_client_init(&config);
      esp_err_t err = esp_http_client_perform(client);
  
      if (err == ESP_OK) {
          ESP_LOGI(TAG, "HTTP Basic Auth Status = %d, content_length = %d",
                  esp_http_client_get_status_code(client),
                  esp_http_client_get_content_length(client));
      } else {
          ESP_LOGE(TAG, "Error perform http request %s", esp_err_to_name(err));
      }
      esp_http_client_cleanup(client);
  }
  
  static void http_auth_basic_redirect()
  {
      esp_http_client_config_t config = {
          .url = "http://user:passwd@httpbin.org/basic-auth/user/passwd",
          .event_handler = _http_event_handler,
      };
      esp_http_client_handle_t client = esp_http_client_init(&config);
      esp_err_t err = esp_http_client_perform(client);
  
      if (err == ESP_OK) {
          ESP_LOGI(TAG, "HTTP Basic Auth redirect Status = %d, content_length = %d",
                  esp_http_client_get_status_code(client),
                  esp_http_client_get_content_length(client));
      } else {
          ESP_LOGE(TAG, "Error perform http request %s", esp_err_to_name(err));
      }
      esp_http_client_cleanup(client);
  }
  
  static void http_auth_digest()
  {
      esp_http_client_config_t config = {
          .url = "http://user:passwd@httpbin.org/digest-auth/auth/user/passwd/MD5/never",
          .event_handler = _http_event_handler,
      };
      esp_http_client_handle_t client = esp_http_client_init(&config);
      esp_err_t err = esp_http_client_perform(client);
  
      if (err == ESP_OK) {
          ESP_LOGI(TAG, "HTTP Digest Auth Status = %d, content_length = %d",
                  esp_http_client_get_status_code(client),
                  esp_http_client_get_content_length(client));
      } else {
          ESP_LOGE(TAG, "Error perform http request %s", esp_err_to_name(err));
      }
      esp_http_client_cleanup(client);
  }
  
  static void https()
  {
      esp_http_client_config_t config = {
          .url = "https://www.howsmyssl.com",
          .event_handler = _http_event_handler,
          .cert_pem = howsmyssl_com_root_cert_pem_start,
      };
      esp_http_client_handle_t client = esp_http_client_init(&config);
      esp_err_t err = esp_http_client_perform(client);
  
      if (err == ESP_OK) {
          ESP_LOGI(TAG, "HTTPS Status = %d, content_length = %d",
                  esp_http_client_get_status_code(client),
                  esp_http_client_get_content_length(client));
      } else {
          ESP_LOGE(TAG, "Error perform http request %s", esp_err_to_name(err));
      }
      esp_http_client_cleanup(client);
  }
  
  static void http_relative_redirect()
  {
      esp_http_client_config_t config = {
          .url = "http://httpbin.org/relative-redirect/3",
          .event_handler = _http_event_handler,
      };
      esp_http_client_handle_t client = esp_http_client_init(&config);
      esp_err_t err = esp_http_client_perform(client);
  
      if (err == ESP_OK) {
          ESP_LOGI(TAG, "HTTP Relative path redirect Status = %d, content_length = %d",
                  esp_http_client_get_status_code(client),
                  esp_http_client_get_content_length(client));
      } else {
          ESP_LOGE(TAG, "Error perform http request %s", esp_err_to_name(err));
      }
      esp_http_client_cleanup(client);
  }
  
  static void http_absolute_redirect()
  {
      esp_http_client_config_t config = {
          .url = "http://httpbin.org/absolute-redirect/3",
          .event_handler = _http_event_handler,
      };
      esp_http_client_handle_t client = esp_http_client_init(&config);
      esp_err_t err = esp_http_client_perform(client);
  
      if (err == ESP_OK) {
          ESP_LOGI(TAG, "HTTP Absolute path redirect Status = %d, content_length = %d",
                  esp_http_client_get_status_code(client),
                  esp_http_client_get_content_length(client));
      } else {
          ESP_LOGE(TAG, "Error perform http request %s", esp_err_to_name(err));
      }
      esp_http_client_cleanup(client);
  }
  
  static void http_redirect_to_https()
  {
      esp_http_client_config_t config = {
          .url = "http://httpbin.org/redirect-to?url=https%3A%2F%2Fwww.howsmyssl.com",
          .event_handler = _http_event_handler,
      };
      esp_http_client_handle_t client = esp_http_client_init(&config);
      esp_err_t err = esp_http_client_perform(client);
  
      if (err == ESP_OK) {
          ESP_LOGI(TAG, "HTTP redirect to HTTPS Status = %d, content_length = %d",
                  esp_http_client_get_status_code(client),
                  esp_http_client_get_content_length(client));
      } else {
          ESP_LOGE(TAG, "Error perform http request %s", esp_err_to_name(err));
      }
      esp_http_client_cleanup(client);
  }
  
  
  static void http_download_chunk()
  {
      esp_http_client_config_t config = {
          .url = "http://httpbin.org/stream-bytes/8912",
          .event_handler = _http_event_handler,
      };
      esp_http_client_handle_t client = esp_http_client_init(&config);
      esp_err_t err = esp_http_client_perform(client);
  
      if (err == ESP_OK) {
          ESP_LOGI(TAG, "HTTP chunk encoding Status = %d, content_length = %d",
                  esp_http_client_get_status_code(client),
                  esp_http_client_get_content_length(client));
      } else {
          ESP_LOGE(TAG, "Error perform http request %s", esp_err_to_name(err));
      }
      esp_http_client_cleanup(client);
  }
  
  static void http_perform_as_stream_reader()
  {
      char *buffer = malloc(MAX_HTTP_RECV_BUFFER);
      if (buffer == NULL) {
          ESP_LOGE(TAG, "Cannot malloc http receive buffer");
          return;
      }
      esp_http_client_config_t config = {
          .url = "http://httpbin.org/get",
          .event_handler = _http_event_handler,
      };
      esp_http_client_handle_t client = esp_http_client_init(&config);
      esp_err_t err;
      if ((err = esp_http_client_open(client, 0)) != ESP_OK) {
          ESP_LOGE(TAG, "Failed to open HTTP connection: %s", esp_err_to_name(err));
          free(buffer);
          return;
      }
      int content_length =  esp_http_client_fetch_headers(client);
      int total_read_len = 0, read_len;
      if (total_read_len < content_length && content_length <= MAX_HTTP_RECV_BUFFER) {
          read_len = esp_http_client_read(client, buffer, content_length);
          if (read_len <= 0) {
              ESP_LOGE(TAG, "Error read data");
          }
          buffer[read_len] = 0;
          ESP_LOGD(TAG, "read_len = %d", read_len);
      }
      ESP_LOGI(TAG, "HTTP Stream reader Status = %d, content_length = %d",
                      esp_http_client_get_status_code(client),
                      esp_http_client_get_content_length(client));
      esp_http_client_close(client);
      esp_http_client_cleanup(client);
      free(buffer);
  }
  
  static void http_test_task(void *pvParameters)
  {
      app_wifi_wait_connected();
      ESP_LOGI(TAG, "Connected to AP, begin http example");
      http_rest();
      http_auth_basic();
      http_auth_basic_redirect();
      http_auth_digest();
      http_relative_redirect();
      http_absolute_redirect();
      https();
      http_redirect_to_https();
      http_download_chunk();
      http_perform_as_stream_reader();
      ESP_LOGI(TAG, "Finish http example");
      vTaskDelete(NULL);
  }
  
  void app_main()
  {
      esp_err_t ret = nvs_flash_init();
      if (ret == ESP_ERR_NVS_NO_FREE_PAGES) {
        ESP_ERROR_CHECK(nvs_flash_erase());
        ret = nvs_flash_init();
      }
      ESP_ERROR_CHECK(ret);
      app_wifi_initialise();
  
      xTaskCreate(&http_test_task, "http_test_task", 8192, NULL, 5, NULL);
  }
  