https_mbedtls_example_main.c

/*|-----------------------------------------------------------------------------------|*/
/*|Project: Water Level Monitor - HTTPS - ESP32 + HC-SR04 / JSN-SR04T / HY-SRF05      |*/
/*|ESP32 (DevKit, Generic) - ESP-IDF v5.2                                             |*/
/*|Author: Martin Chlebovec (martinius96)                                             |*/
/*|E-mail: martinius96@gmail.com                                                      |*/
/*|More info: https://martinius96.github.io/hladinomer-studna-scripty/en              |*/
/*|Test web interface for HTTPS protocol: https://hladinomer.eu/?lang=en              |*/
/*|Revision: 5th Nov 2024                                                             |*/
/*|-----------------------------------------------------------------------------------|*/

#include <string.h>
#include <stdlib.h>
#include <inttypes.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_wifi.h"
#include "esp_event.h"
#include "esp_log.h"
#include "esp_system.h"
#include "nvs_flash.h"
#include "protocol_examples_common.h"
#include "esp_netif.h"

#include "lwip/err.h"
#include "lwip/sockets.h"
#include "lwip/sys.h"
#include "lwip/netdb.h"
#include "lwip/dns.h"

#include "mbedtls/platform.h"
#include "mbedtls/net_sockets.h"
#include "mbedtls/esp_debug.h"
#include "mbedtls/ssl.h"
#include "mbedtls/entropy.h"
#include "mbedtls/ctr_drbg.h"
#include "mbedtls/error.h"
#ifdef CONFIG_MBEDTLS_SSL_PROTO_TLS1_3
#include "psa/crypto.h"
#endif
#include "esp_crt_bundle.h"

#include "ultrasonic.h"

/* Constants that aren't configurable in menuconfig */

#define MAX_DISTANCE_CM 450 // 5m max
#define GPIO_TRIGGER	22 //wire to Trigger pin of HC-SR04
#define GPIO_ECHO	23 //wire to Echo pin of HC-SR04

// Webserver
/* Constants that aren't configurable in menuconfig */
#define WEB_SERVER "hladinomer.eu"
#define WEB_PORT "443"


static const char *TAG = "https_request"; //prints from HTTPS task
static const char *TAG2 = "ultrasonic_measurement"; //prints from ultrasonic measurement task

QueueHandle_t  q=NULL;
static void ultrasonic(void *pvParamters)
{
	ultrasonic_sensor_t sensor = {
		.trigger_pin = GPIO_TRIGGER,
		.echo_pin = GPIO_ECHO
	};

	ultrasonic_init(&sensor);
  uint32_t distance = 0;
    if(q == NULL){
        printf("Queue is not ready \n");
        return;
    }
	while (true) {
  uint32_t avg_distance = 0;
  int index_loop = 1;
  while(index_loop<=10){
		esp_err_t res = ultrasonic_measure_cm(&sensor, MAX_DISTANCE_CM, &distance);
		if (res != ESP_OK) {
			printf("Error: ");
			switch (res) {
				case ESP_ERR_ULTRASONIC_PING:
					printf("Cannot ping (device is in invalid state)\n");
					break;
				case ESP_ERR_ULTRASONIC_PING_TIMEOUT:
					printf("Ping timeout (no device found)\n");
					break;
				case ESP_ERR_ULTRASONIC_ECHO_TIMEOUT:
					printf("Echo timeout (i.e. distance too big)\n");
					break;
				default:
					printf("%d\n", res);
			}
		} else {
			printf("Measurement %d: %ld cm\n", index_loop, distance);
       avg_distance +=  distance;
      index_loop++;
		}
    }
    esp_err_t res = ultrasonic_measure_cm(&sensor, MAX_DISTANCE_CM, &distance);
    if (res == ESP_OK) {
      avg_distance = avg_distance / 10;
      distance  = avg_distance;
      xQueueSend(q,(void *)&distance,(TickType_t )0); // add the value to the queue
    }
            for(int countdown = 300; countdown >= 0; countdown--) { //300s countdown before sending again
            ESP_LOGI(TAG2, "%d... ", countdown);
            vTaskDelay(1000 / portTICK_PERIOD_MS);
        }
	}
}

static void https_get_task(void *pvParameters)
{
     uint32_t distance;
     if(q == NULL){
        printf("Queue is not ready \n");
        return;
    }
    char buf[512];
    int ret, flags, len;

    mbedtls_entropy_context entropy;
    mbedtls_ctr_drbg_context ctr_drbg;
    mbedtls_ssl_context ssl;
    mbedtls_x509_crt cacert;
    mbedtls_ssl_config conf;
    mbedtls_net_context server_fd;

#ifdef CONFIG_MBEDTLS_SSL_PROTO_TLS1_3
    psa_status_t status = psa_crypto_init();
    if (status != PSA_SUCCESS) {
        ESP_LOGE(TAG, "Failed to initialize PSA crypto, returned %d", (int) status);
        return;
    }
#endif

    mbedtls_ssl_init(&ssl);
    mbedtls_x509_crt_init(&cacert);
    mbedtls_ctr_drbg_init(&ctr_drbg);
    ESP_LOGI(TAG, "Seeding the random number generator");

    mbedtls_ssl_config_init(&conf);

    mbedtls_entropy_init(&entropy);
    if((ret = mbedtls_ctr_drbg_seed(&ctr_drbg, mbedtls_entropy_func, &entropy,
                                    NULL, 0)) != 0)
    {
        ESP_LOGE(TAG, "mbedtls_ctr_drbg_seed returned %d", ret);
        abort();
    }

    ESP_LOGI(TAG, "Attaching the certificate bundle...");

    ret = esp_crt_bundle_attach(&conf);

    if(ret < 0)
    {
        ESP_LOGE(TAG, "esp_crt_bundle_attach returned -0x%x", -ret);
        abort();
    }

    ESP_LOGI(TAG, "Setting hostname for TLS session...");

     /* Hostname set here should match CN in server certificate */
    if((ret = mbedtls_ssl_set_hostname(&ssl, WEB_SERVER)) != 0)
    {
        ESP_LOGE(TAG, "mbedtls_ssl_set_hostname returned -0x%x", -ret);
        abort();
    }

    ESP_LOGI(TAG, "Setting up the SSL/TLS structure...");

    if((ret = mbedtls_ssl_config_defaults(&conf,
                                          MBEDTLS_SSL_IS_CLIENT,
                                          MBEDTLS_SSL_TRANSPORT_STREAM,
                                          MBEDTLS_SSL_PRESET_DEFAULT)) != 0)
    {
        ESP_LOGE(TAG, "mbedtls_ssl_config_defaults returned %d", ret);
        goto exit;
    }

    mbedtls_ssl_conf_authmode(&conf, MBEDTLS_SSL_VERIFY_REQUIRED);
    mbedtls_ssl_conf_ca_chain(&conf, &cacert, NULL);
    mbedtls_ssl_conf_rng(&conf, mbedtls_ctr_drbg_random, &ctr_drbg);
#ifdef CONFIG_MBEDTLS_DEBUG
    mbedtls_esp_enable_debug_log(&conf, CONFIG_MBEDTLS_DEBUG_LEVEL);
#endif

    if ((ret = mbedtls_ssl_setup(&ssl, &conf)) != 0)
    {
        ESP_LOGE(TAG, "mbedtls_ssl_setup returned -0x%x", -ret);
        goto exit;
    }

    while(1) {
  	xQueueReceive(q,&distance,portMAX_DELAY); //CODE BELOW WILL EXECUTE ONLY WHEN DATA ARRIVE TO QUEUE, UNTIL THAT IT WAITS, MAXIMUM portMAX_DELAY = ALMOST 50 DAYS (never happen as ultrasonic measurement adds value each 300 seconds)
  	char REQUEST [1000];
  	char values [250];
	sprintf(values, "hodnota=%ld&token=123456789", distance);
    	sprintf (REQUEST, "POST /data.php HTTP/1.0\r\nHost: "WEB_SERVER"\r\nUser-Agent: ESP32\r\nConnection: close\r\nContent-Type: application/x-www-form-urlencoded;\r\nContent-Length:%d\r\n\r\n%s\r\n",strlen(values),values); 
        mbedtls_net_init(&server_fd);
        ESP_LOGI(TAG, "Connecting to %s:%s...", WEB_SERVER, WEB_PORT);
        if ((ret = mbedtls_net_connect(&server_fd, WEB_SERVER, WEB_PORT, MBEDTLS_NET_PROTO_TCP)) != 0)
        {
            ESP_LOGE(TAG, "mbedtls_net_connect returned -%x", -ret);
            goto exit;
        }
        ESP_LOGI(TAG, "Connected.");
        mbedtls_ssl_set_bio(&ssl, &server_fd, mbedtls_net_send, mbedtls_net_recv, NULL);
        ESP_LOGI(TAG, "Performing the SSL/TLS handshake...");
        while ((ret = mbedtls_ssl_handshake(&ssl)) != 0)
        {
            if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE)
            {
                ESP_LOGE(TAG, "mbedtls_ssl_handshake returned -0x%x", -ret);
                goto exit;
            }
        }

        ESP_LOGI(TAG, "Verifying peer X.509 certificate...");

        if ((flags = mbedtls_ssl_get_verify_result(&ssl)) != 0)
        {
            /* In real life, we probably want to close connection if ret != 0 */
            ESP_LOGW(TAG, "Failed to verify peer certificate!");
            bzero(buf, sizeof(buf));
            mbedtls_x509_crt_verify_info(buf, sizeof(buf), "  ! ", flags);
            ESP_LOGW(TAG, "verification info: %s", buf);
        }
        else {
            ESP_LOGI(TAG, "Certificate verified.");
        }

        ESP_LOGI(TAG, "Cipher suite is %s", mbedtls_ssl_get_ciphersuite(&ssl));

        ESP_LOGI(TAG, "Writing HTTP request...");

        size_t written_bytes = 0;
        do {
            ret = mbedtls_ssl_write(&ssl,
                                    (unsigned char *)REQUEST + written_bytes,
                                    strlen(REQUEST) - written_bytes);
            if (ret >= 0) {
                ESP_LOGI(TAG, "%d bytes written", ret);
                written_bytes += ret;
            } else if (ret != MBEDTLS_ERR_SSL_WANT_WRITE && ret != MBEDTLS_ERR_SSL_WANT_READ) {
                ESP_LOGE(TAG, "mbedtls_ssl_write returned -0x%x", -ret);
                goto exit;
            }
        } while(written_bytes < strlen(REQUEST));

        ESP_LOGI(TAG, "Reading HTTP response...");

        do
        {
            len = sizeof(buf) - 1;
            bzero(buf, sizeof(buf));
            ret = mbedtls_ssl_read(&ssl, (unsigned char *)buf, len);
#if CONFIG_MBEDTLS_SSL_PROTO_TLS1_3 && CONFIG_MBEDTLS_CLIENT_SSL_SESSION_TICKETS
            if (ret == MBEDTLS_ERR_SSL_RECEIVED_NEW_SESSION_TICKET) {
                ESP_LOGD(TAG, "got session ticket in TLS 1.3 connection, retry read");
                continue;
            }
#endif // CONFIG_MBEDTLS_SSL_PROTO_TLS1_3 && CONFIG_MBEDTLS_CLIENT_SSL_SESSION_TICKETS
            if(ret == MBEDTLS_ERR_SSL_WANT_READ || ret == MBEDTLS_ERR_SSL_WANT_WRITE)
                continue;

            if(ret == MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY) {
                ret = 0;
                break;
            }

            if(ret < 0)
            {
                ESP_LOGE(TAG, "mbedtls_ssl_read returned -0x%x", -ret);
                break;
            }

            if(ret == 0)
            {
                ESP_LOGI(TAG, "connection closed");
                break;
            }

            len = ret;
            ESP_LOGD(TAG, "%d bytes read", len);
            /* Print response directly to stdout as it is read */
            for(int i = 0; i < len; i++) {
                putchar(buf[i]);
            }
        } while(1);

        mbedtls_ssl_close_notify(&ssl);

    exit:
        mbedtls_ssl_session_reset(&ssl);
        mbedtls_net_free(&server_fd);

        if(ret != 0)
        {
            mbedtls_strerror(ret, buf, 100);
            ESP_LOGE(TAG, "Last error was: -0x%x - %s", -ret, buf);
        }

        putchar('\n'); // JSON output doesn't have a newline at end

        static int request_count;
        ESP_LOGI(TAG, "Completed %d requests", ++request_count);
        ESP_LOGI(TAG, "Starting again!");
    }
}

void app_main(void)
{
    ESP_ERROR_CHECK( nvs_flash_init() );
    ESP_ERROR_CHECK(esp_netif_init());
    ESP_ERROR_CHECK(esp_event_loop_create_default());

    /* This helper function configures Wi-Fi or Ethernet, as selected in menuconfig.
     * Read "Establishing Wi-Fi or Ethernet Connection" section in
     * examples/protocols/README.md for more information about this function.
     */
    ESP_ERROR_CHECK(example_connect());
     q=xQueueCreate(20, sizeof(unsigned long)); //Create queue with 20 values of unsigned long size
    if(q != NULL){
        printf("Queue is created\n");
        vTaskDelay(1000/portTICK_PERIOD_MS); //wait for a second
        xTaskCreate(&ultrasonic, "ultrasonic", 2048, NULL, 5, NULL);
        printf("Measurement task  started\n");
        xTaskCreate(&https_get_task, "https_get_task", 8192, NULL, 5, NULL);
        printf("HTTPS socket task  started\n");
    }else{
        printf("Queue creation failed");
    }  
}