esp idf wifi tcp数据发送例程

以下是 ESP-IDF 中使用 WiFi TCP 发送数据的示例代码：

#include <stdio.h>
#include <string.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_wifi.h"
#include "esp_event_loop.h"
#include "esp_log.h"
#include "tcpip_adapter.h"

#define EXAMPLE_ESP_WIFI_SSID      "your_wifi_ssid"
#define EXAMPLE_ESP_WIFI_PASS      "your_wifi_password"
#define EXAMPLE_ESP_MAXIMUM_RETRY  3

static const char *TAG = "example";

static EventGroupHandle_t s_wifi_event_group;
const int WIFI_CONNECTED_BIT = BIT0;
static int s_retry_num = 0;

static void wifi_event_handler(void* arg, esp_event_base_t event_base,
                                int32_t event_id, void* event_data)
{
    if (event_id == WIFI_EVENT_STA_START) {
        esp_wifi_connect();
    } else if (event_id == WIFI_EVENT_STA_DISCONNECTED) {
        if (s_retry_num < EXAMPLE_ESP_MAXIMUM_RETRY) {
            esp_wifi_connect();
            s_retry_num++;
            ESP_LOGI(TAG, "retry to connect to the AP");
        }
        ESP_LOGI(TAG,"connect to the AP fail");
    } else if (event_id == IP_EVENT_STA_GOT_IP) {
        ip_event_got_ip_t* event = (ip_event_got_ip_t*) event_data;
        ESP_LOGI(TAG, "got ip:" IPSTR, IP2STR(&event->ip_info.ip));
        s_retry_num = 0;
        xEventGroupSetBits(s_wifi_event_group, WIFI_CONNECTED_BIT);
    }
}

void wifi_init_sta(void)
{
    s_wifi_event_group = xEventGroupCreate();

    tcpip_adapter_init();

    ESP_ERROR_CHECK(esp_event_loop_create_default());

    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
    ESP_ERROR_CHECK(esp_wifi_init(&cfg));

    wifi_config_t wifi_config = {
        .sta = {
            .ssid = EXAMPLE_ESP_WIFI_SSID,
            .password = EXAMPLE_ESP_WIFI_PASS,
        },
    };

    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA));
    ESP_ERROR_CHECK(esp_wifi_set_config(ESP_IF_WIFI_STA, &wifi_config));
    ESP_ERROR_CHECK(esp_wifi_start());

    ESP_LOGI(TAG, "wifi_init_sta finished.");

    xEventGroupWaitBits(s_wifi_event_group, WIFI_CONNECTED_BIT, false, true, portMAX_DELAY);
}

void tcp_client_task(void *pvParameters)
{
    char buffer[128];
    int sock = socket(AF_INET, SOCK_STREAM, IPPROTO_IP);
    if (sock < 0) {
        ESP_LOGE(TAG, "Unable to create socket: errno %d", errno);
        vTaskDelete(NULL);
        return;
    }

    struct sockaddr_in server_address;
    server_address.sin_family = AF_INET;
    server_address.sin_addr.s_addr = inet_addr("192.168.1.100");
    server_address.sin_port = htons(8080);

    int err = connect(sock, (struct sockaddr *)&server_address, sizeof(server_address));
    if (err != 0) {
        ESP_LOGE(TAG, "Socket unable to connect: errno %d", errno);
        close(sock);
        vTaskDelete(NULL);
        return;
    }

    while (1) {
        sprintf(buffer, "Hello from ESP32!");
        int err = send(sock, buffer, strlen(buffer), 0);
        if (err < 0) {
            ESP_LOGE(TAG, "Error occurred during sending: errno %d", errno);
            break;
        }
        vTaskDelay(2000 / portTICK_PERIOD_MS);
    }

    shutdown(sock, 0);
    close(sock);
    vTaskDelete(NULL);
}

void app_main()
{
    ESP_LOGI(TAG, "ESP_WIFI_MODE_STA");
    wifi_init_sta();

    xTaskCreate(tcp_client_task, "tcp_client", 4096, NULL, 5, NULL);
}

以上代码实现了一个 TCP 客户端任务，与 IP 地址为 192.168.1.100、端口号为 8080 的服务器建立连接，并每隔 2 秒发送一条字符串数据。在使用时需要将 EXAMPLE_ESP_WIFI_SSID 和 EXAMPLE_ESP_WIFI_PASS 替换为实际的 WiFi SSID 和密码，并且根据实际情况修改服务器的 IP 地址和端口号。