esp-idf/examples/protocols/websocket/main/websocket_example.c

/* ESP HTTP Client Example

   This example code is in the Public Domain (or CC0 licensed, at your option.)

   Unless required by applicable law or agreed to in writing, this
   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
   CONDITIONS OF ANY KIND, either express or implied.
*/


#include <stdio.h>
#include "esp_wifi.h"
#include "esp_system.h"
#include "nvs_flash.h"
#include "esp_event_loop.h"

#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/semphr.h"
#include "freertos/event_groups.h"


#include "esp_log.h"
#include "esp_websocket_client.h"
#include "esp_event.h"

#define NO_DATA_TIMEOUT_SEC 10

static const char *TAG = "WEBSOCKET";

static EventGroupHandle_t wifi_event_group;
const static int CONNECTED_BIT = BIT0;

static TimerHandle_t shutdown_signal_timer;
static SemaphoreHandle_t shutdown_sema;

static void shutdown_signaler(TimerHandle_t xTimer)
{
    ESP_LOGI(TAG, "No data received for %d seconds, signaling shutdown", NO_DATA_TIMEOUT_SEC);
    xSemaphoreGive(shutdown_sema);
}

#if CONFIG_WEBSOCKET_URI_FROM_STDIN
static void get_string(char *line, size_t size)
{
    int count = 0;
    while (count < size) {
        int c = fgetc(stdin);
        if (c == '\n') {
            line[count] = '\0';
            break;
        } else if (c > 0 && c < 127) {
            line[count] = c;
            ++count;
        }
        vTaskDelay(10 / portTICK_PERIOD_MS);
    }
}

#endif /* CONFIG_WEBSOCKET_URI_FROM_STDIN */

static void websocket_event_handler(void *handler_args, esp_event_base_t base, int32_t event_id, void *event_data)
{
    esp_websocket_event_data_t *data = (esp_websocket_event_data_t *)event_data;
    switch (event_id) {
    case WEBSOCKET_EVENT_CONNECTED:
        ESP_LOGI(TAG, "WEBSOCKET_EVENT_CONNECTED");
        break;
    case WEBSOCKET_EVENT_DISCONNECTED:
        ESP_LOGI(TAG, "WEBSOCKET_EVENT_DISCONNECTED");
        break;
    case WEBSOCKET_EVENT_DATA:
        ESP_LOGI(TAG, "WEBSOCKET_EVENT_DATA");
        ESP_LOGI(TAG, "Received opcode=%d", data->op_code);
        ESP_LOGW(TAG, "Received=%.*s", data->data_len, (char *)data->data_ptr);
        ESP_LOGW(TAG, "Total payload length=%d, data_len=%d, current payload offset=%d\r\n", data->payload_len, data->data_len, data->payload_offset);

        xTimerReset(shutdown_signal_timer, portMAX_DELAY);
        break;
    case WEBSOCKET_EVENT_ERROR:
        ESP_LOGI(TAG, "WEBSOCKET_EVENT_ERROR");
        break;
    }
}

static esp_err_t wifi_event_handler(void *ctx, system_event_t *event)
{
    switch (event->event_id) {
        case SYSTEM_EVENT_STA_START:
            esp_wifi_connect();
            break;
        case SYSTEM_EVENT_STA_GOT_IP:
            xEventGroupSetBits(wifi_event_group, CONNECTED_BIT);

            break;
        case SYSTEM_EVENT_STA_DISCONNECTED:
            esp_wifi_connect();
            xEventGroupClearBits(wifi_event_group, CONNECTED_BIT);
            break;
        default:
            break;
    }
    return ESP_OK;
}

static void wifi_init(void)
{
    tcpip_adapter_init();
    wifi_event_group = xEventGroupCreate();
    ESP_ERROR_CHECK(esp_event_loop_init(wifi_event_handler, NULL));
    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
    ESP_ERROR_CHECK(esp_wifi_init(&cfg));
    ESP_ERROR_CHECK(esp_wifi_set_storage(WIFI_STORAGE_RAM));
    wifi_config_t wifi_config = {
        .sta = {
            .ssid = CONFIG_WIFI_SSID,
            .password = CONFIG_WIFI_PASSWORD,
        },
    };
    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA));
    ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_STA, &wifi_config));
    ESP_LOGI(TAG, "start the WIFI SSID:[%s]", CONFIG_WIFI_SSID);
    ESP_ERROR_CHECK(esp_wifi_start());
    ESP_LOGI(TAG, "Waiting for wifi");
    xEventGroupWaitBits(wifi_event_group, CONNECTED_BIT, false, true, portMAX_DELAY);
}

static void websocket_app_start(void)
{
    esp_websocket_client_config_t websocket_cfg = {};

    shutdown_signal_timer = xTimerCreate("Websocket shutdown timer", NO_DATA_TIMEOUT_SEC * 1000 / portTICK_PERIOD_MS,
                                         pdFALSE, NULL, shutdown_signaler);
    shutdown_sema = xSemaphoreCreateBinary();

#if CONFIG_WEBSOCKET_URI_FROM_STDIN
    char line[128];

    ESP_LOGI(TAG, "Please enter uri of websocket endpoint");
    get_string(line, sizeof(line));

    websocket_cfg.uri = line;
    ESP_LOGI(TAG, "Endpoint uri: %s\n", line);

#else
    websocket_cfg.uri = CONFIG_WEBSOCKET_URI;

#endif /* CONFIG_WEBSOCKET_URI_FROM_STDIN */

    ESP_LOGI(TAG, "Connecting to %s...", websocket_cfg.uri);

    esp_websocket_client_handle_t client = esp_websocket_client_init(&websocket_cfg);
    esp_websocket_register_events(client, WEBSOCKET_EVENT_ANY, websocket_event_handler, (void *)client);

    esp_websocket_client_start(client);
    xTimerStart(shutdown_signal_timer, portMAX_DELAY);
    char data[32];
    int i = 0;
    while (i < 10) {
        if (esp_websocket_client_is_connected(client)) {
            int len = sprintf(data, "hello %04d", i++);
            ESP_LOGI(TAG, "Sending %s", data);
            esp_websocket_client_send(client, data, len, portMAX_DELAY);
        }
        vTaskDelay(1000 / portTICK_RATE_MS);
    }

    xSemaphoreTake(shutdown_sema, portMAX_DELAY);
    esp_websocket_client_stop(client);
    ESP_LOGI(TAG, "Websocket Stopped");
    esp_websocket_client_destroy(client);
}

void app_main(void)
{
    ESP_LOGI(TAG, "[APP] Startup..");
    ESP_LOGI(TAG, "[APP] Free memory: %d bytes", esp_get_free_heap_size());
    ESP_LOGI(TAG, "[APP] IDF version: %s", esp_get_idf_version());

    esp_log_level_set("*", ESP_LOG_INFO);
    esp_log_level_set("WEBSOCKET_CLIENT", ESP_LOG_DEBUG);
    esp_log_level_set("TRANS_TCP", ESP_LOG_DEBUG);

    nvs_flash_init();
    wifi_init();
    websocket_app_start();
}