I have a doubt with the handling of the heap when using esp_http_client.
Every time I make a new request, the heap decreases (I attach the image) after several requests the heap remains at a static value (red box in the image), this last value is what I would expect since I am making the same request with a very similar answer.
What is the reason that when making a new request the heap decreases?
I already checked and I don't have any malloc without free() ... is there a reason for this to happen?
I am relying on the example of esp_http_client... I attach my code
esp-idf: v4.3-dev-2586-g526f68239
- #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 "esp_event.h"
- #include "esp_netif.h"
- #include "protocol_examples_common.h"
- #include "esp_tls.h"
- #include "esp_http_client.h"
- #define MAX_HTTP_RECV_BUFFER 512
- #define MAX_HTTP_OUTPUT_BUFFER 2048
- static const char *TAG = "HTTP_CLIENT";
- esp_err_t _http_event_handler(esp_http_client_event_t *evt)
- {
- static char *output_buffer; // Buffer to store response of http request from event handler
- static int output_len; // Stores number of bytes read
- 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);
- /*
- * Check for chunked encoding is added as the URL for chunked encoding used in this example returns binary data.
- * However, event handler can also be used in case chunked encoding is used.
- */
- if (!esp_http_client_is_chunked_response(evt->client)) {
- // If user_data buffer is configured, copy the response into the buffer
- if (evt->user_data) {
- memcpy(evt->user_data + output_len, evt->data, evt->data_len);
- } else {
- if (output_buffer == NULL) {
- output_buffer = (char *) malloc(esp_http_client_get_content_length(evt->client));
- output_len = 0;
- if (output_buffer == NULL) {
- ESP_LOGE(TAG, "Failed to allocate memory for output buffer");
- return ESP_FAIL;
- }
- }
- memcpy(output_buffer + output_len, evt->data, evt->data_len);
- }
- output_len += evt->data_len;
- }
- break;
- case HTTP_EVENT_ON_FINISH:
- ESP_LOGD(TAG, "HTTP_EVENT_ON_FINISH");
- if (output_buffer != NULL) {
- // Response is accumulated in output_buffer. Uncomment the below line to print the accumulated response
- // ESP_LOG_BUFFER_HEX(TAG, output_buffer, output_len);
- free(output_buffer);
- output_buffer = NULL;
- }
- output_len = 0;
- break;
- case HTTP_EVENT_DISCONNECTED:
- ESP_LOGI(TAG, "HTTP_EVENT_DISCONNECTED");
- int mbedtls_err = 0;
- esp_err_t err = esp_tls_get_and_clear_last_error(evt->data, &mbedtls_err, NULL);
- if (err != 0) {
- if (output_buffer != NULL) {
- free(output_buffer);
- output_buffer = NULL;
- }
- output_len = 0;
- ESP_LOGI(TAG, "Last esp error code: 0x%x", err);
- ESP_LOGI(TAG, "Last mbedtls failure: 0x%x", mbedtls_err);
- }
- break;
- }
- return ESP_OK;
- }
- static void http_rest_with_url(void)
- {
- char local_response_buffer[MAX_HTTP_OUTPUT_BUFFER] = {0};
- esp_http_client_config_t config = {
- .host = "httpbin.org",
- .path = "/get",
- .query = "esp",
- .event_handler = _http_event_handler,
- .user_data = local_response_buffer, // Pass address of local buffer to get response
- .disable_auto_redirect = true,
- };
- 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));
- }
- esp_http_client_cleanup(client);
- }
- static void http_test_task(void *pvParameters)
- {
- while (1)
- {
- vTaskDelay(5000 / portTICK_PERIOD_MS);
- http_rest_with_url();
- printf("Heap %d \r\n", esp_get_free_heap_size());
- }
- vTaskDelete(NULL);
- }
- void app_main(void)
- {
- esp_err_t ret = nvs_flash_init();
- if (ret == ESP_ERR_NVS_NO_FREE_PAGES || ret == ESP_ERR_NVS_NEW_VERSION_FOUND)
- {
- ESP_ERROR_CHECK(nvs_flash_erase());
- ret = nvs_flash_init();
- }
- ESP_ERROR_CHECK(ret);
- ESP_ERROR_CHECK(esp_netif_init());
- ESP_ERROR_CHECK(esp_event_loop_create_default());
- ESP_ERROR_CHECK(example_connect());
- ESP_LOGI(TAG, "Connected to AP, begin http example");
- xTaskCreate(&http_test_task, "http_test_task", 8192, NULL, 5, NULL);
- }