参考教程

ESP-IDF HTTP获取网络时间

1.使用的http连接

http://api.m.taobao.com/rest/api3.do?api=mtop.common.getTimestamp

请求可以得到下面Json数据

2.使用Vscode-IDF创建http_request例程

创建例程后,在设置中输入wifi的账号密码

3.修改http_request_example_main.c函数

http_request_example_main.c

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

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

#include <cJSON.h>
#include "esp_http_client.h"

static const char *TAG = "example";

#define MAX_HTTP_OUTPUT_BUFFER 2048 // http最大数据接收大小
bool gettime = true;                // 是否从网络请求时间
esp_err_t _http_event_handler(esp_http_client_event_t *evt)
{
    /*switch判断事件代码提示出错可以写成if方式
    switch (evt->event_id)
    {
        case HTTP_EVENT_ERROR:
            ESP_LOGI(TAG, "HTTP_EVENT_ERROR");
            break;
        case HTTP_EVENT_ON_CONNECTED:
            ESP_LOGI(TAG, "HTTP_EVENT_ON_CONNECTED");
            break;
        case HTTP_EVENT_HEADER_SENT:
            ESP_LOGI(TAG, "HTTP_EVENT_HEADER_SENT");
            break;
        case HTTP_EVENT_ON_HEADER:
            ESP_LOGI(TAG, "HTTP_EVENT_ON_HEADER");
            printf("%.*s", evt->data_len, (char *)evt->data);
            break;
        case HTTP_EVENT_ON_DATA:
            ESP_LOGI(TAG, "HTTP_EVENT_ON_DATA,len=%d", evt->data_len);
            if (!esp_http_client_is_chunked_response(evt->client))
            {
                printf("%.*s", evt->data_len, (char *)evt->data);
            }
            break;
        case HTTP_EVENT_ON_FINISH://http完成事件
            ESP_LOGI(TAG, "HTTP_EVENT_ON_FINISH");
            break;
        case HTTP_EVENT_DISCONNECTED://http断开连接事件
            ESP_LOGI(TAG, "HTTP_EVENT_DISCONNECTED");
            break;
    }
    */
    if (evt->event_id == HTTP_EVENT_ON_DATA) // 收到数据事件
    {

        ESP_LOGI(TAG, "HTTP_EVENT_ON_DATA,len=%d", evt->data_len);
        if (!esp_http_client_is_chunked_response(evt->client))
        {
            ESP_LOGI(TAG, "响应:%s", (char *)evt->data);
            //     cJSON *json = cJSON_Parse(evt->data); // cJSON解析json格式数据
            //     cJSON *time_json = cJSON_GetObjectItem(json, "data");
            //     char *timestamp = cJSON_GetObjectItem(time_json, "t")->valuestring;
            //     printf("%.*s", evt->data_len, (char *)evt->data);

            //     struct timeval now = {.tv_sec = (atoll(timestamp) / 1000)}; // 从网上获取到的时间戳要除1000
            //     settimeofday(&now, NULL);                                   // ESPIDF官方提供的设置时间函数

            //     cJSON_Delete(json);
        }
    }
    return ESP_OK;
}
static void http_get_task(void *pvParameters)
{
    while (gettime)
    {
        char local_response_buffer[MAX_HTTP_OUTPUT_BUFFER] = {0};
        esp_http_client_config_t config = {
            .method = HTTP_METHOD_GET, // get方式请求数据
            .url = "http://api.m.taobao.com/rest/api3.do?api=mtop.common.getTimestamp",
            .event_handler = _http_event_handler,
            .user_data = local_response_buffer,
        };
        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 GET Status = %d, content_length = %d",
                     esp_http_client_get_status_code(client),
                     (int)esp_http_client_get_content_length(client));

            gettime = false;
        }
        else
        {
            ESP_LOGI(TAG, "HTTP GET request failed: %s", esp_err_to_name(err));
        }

        ESP_LOGI(TAG, "%s\n", local_response_buffer);
        esp_http_client_cleanup(client);
        vTaskDelay(1000 / portTICK_PERIOD_MS);
    }
    while (1)
    {
        vTaskDelay(1000 / portTICK_PERIOD_MS);
    }
}

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

    ESP_ERROR_CHECK(example_connect());

    xTaskCreate(&http_get_task, "http_get_task", 4096, NULL, 5, NULL);
}

4.已经获取到响应的数据