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
Code: Untitled.c Select all
#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);
}