Minimales ESP32 NimBLE-Beispiel für die Ausführung benutzerdefinierter Befehle über BLE

#include "CustomBLE.hpp"

#include "esp_log.h"
#include "esp_system.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "nimble/nimble_port.h"
#include "nimble/nimble_port_freertos.h"
#include "host/ble_hs.h"
#include "host/ble_uuid.h"
#include "host/ble_gatt.h"
#include "services/gap/ble_svc_gap.h"
#include "services/gatt/ble_svc_gatt.h"

#include <string>
#include <cstring>

static const char *TAG = "CustomBLE";

// Benutzerdefinierte Service- und Charakteristik-UUIDs (zufällig generierte 128-Bit-UUIDs)
static const ble_uuid128_t custom_service_uuid =
    BLE_UUID128_INIT(0xF0, 0xDE, 0xBC, 0x9A, 0x78, 0x56, 0x34, 0x12,
                     0xF0, 0xDE, 0xBC, 0x9A, 0x78, 0x56, 0x34, 0x12);

static const ble_uuid128_t command_char_uuid =
    BLE_UUID128_INIT(0x98, 0xBA, 0xDC, 0xFE, 0x21, 0x43, 0x65, 0x87,
                     0x98, 0xBA, 0xDC, 0xFE, 0x21, 0x43, 0x65, 0x87);

static uint16_t command_char_handle;
static uint16_t conn_handle = BLE_HS_CONN_HANDLE_NONE;

// Befehlskonstanten
#define RESTART_COMMAND "RESTART"

// GAP Event-Listener-Struktur
static struct ble_gap_event_listener gap_event_listener;

// GATT Charakteristik-Zugriffsfunktion für Befehle
static int command_char_access(uint16_t conn_handle, uint16_t attr_handle,
                               struct ble_gatt_access_ctxt *ctxt, void *arg) {
    int rc;

    switch (ctxt->op) {
        case BLE_GATT_ACCESS_OP_READ_CHR: {
            ESP_LOGI(TAG, "Command characteristic read - returning status");
            const char* status_msg = "Command interface ready";
            rc = os_mbuf_append(ctxt->om, status_msg, strlen(status_msg));
            return rc == 0 ? 0 : BLE_ATT_ERR_INSUFFICIENT_RES;
        }
        case BLE_GATT_ACCESS_OP_WRITE_CHR: {
            ESP_LOGI(TAG, "Command characteristic write received");
            uint16_t om_len = OS_MBUF_PKTLEN(ctxt->om);
            if (om_len > 0) {
                char buffer[om_len + 1];
                rc = ble_hs_mbuf_to_flat(ctxt->om, buffer, sizeof(buffer) - 1, NULL);
                if (rc == 0) {
                    buffer[om_len] = '\0';
                    ESP_LOGI(TAG, "Received command: %s", buffer);
                    // Befehl verarbeiten
                    if (strcmp(buffer, RESTART_COMMAND) == 0) {
                        ESP_LOGI(TAG, "Restart command received - restarting ESP32...");
                        // Kleine Verzögerung hinzufügen, damit die BLE-Antwort gesendet werden kann
                        vTaskDelay(pdMS_TO_TICKS(100));
                        esp_restart();
                    } else {
                        ESP_LOGW(TAG, "Unknown command: %s", buffer);
                    }
                }
            }
            return 0;
        }
        default: {
            return BLE_ATT_ERR_UNLIKELY;
        }
    }
}

// GATT Service-Definition
static const struct ble_gatt_svc_def custom_gatt_svcs[] = {
    {
        BLE_GATT_SVC_TYPE_PRIMARY,
        &custom_service_uuid.u,
        NULL, // Includes
        (struct ble_gatt_chr_def[]) {
            {
                &command_char_uuid.u,
                command_char_access,
                NULL, // arg
                NULL, // Deskriptoren
                BLE_GATT_CHR_F_READ | BLE_GATT_CHR_F_WRITE,
                0, // min_key_size
                &command_char_handle,
                NULL, // cpfd
            },
            {
                NULL, // uuid - Ende der Charakteristiken
            }
        },
    },
    {
        0, // type - Ende der Services
    }
};

// GAP Event-Handler
static int custom_gap_event(struct ble_gap_event *event, void *arg) {
    switch (event->type) {
        case BLE_GAP_EVENT_CONNECT:
            ESP_LOGI(TAG, "Connection %s; status=%d",
                    event->connect.status == 0 ? "established" : "failed",
                    event->connect.status);
            if (event->connect.status == 0) {
                conn_handle = event->connect.conn_handle;
            }
            break;

        case BLE_GAP_EVENT_DISCONNECT:
            ESP_LOGI(TAG, "Disconnect; reason=%d", event->disconnect.reason);
            conn_handle = BLE_HS_CONN_HANDLE_NONE;
            break;

        default:
            break;
    }
    return 0;
}

void InitCustomBLE() {
    int rc;

    // GATT Services initialisieren
    rc = ble_gatts_count_cfg(custom_gatt_svcs);
    if (rc != 0) {
        ESP_LOGE(TAG, "Failed to count GATT services: %d", rc);
        return;
    }

    rc = ble_gatts_add_svcs(custom_gatt_svcs);
    if (rc != 0) {
        ESP_LOGE(TAG, "Failed to add GATT services: %d", rc);
        return;
    }

    ESP_LOGI(TAG, "Custom NimBLE command service initialized");
}

void ExecuteBLECommand(const std::string& command) {
    ESP_LOGI(TAG, "Executing BLE command: %s", command.c_str());

    if (command == RESTART_COMMAND) {
        ESP_LOGI(TAG, "Restart command executed - restarting ESP32...");
        vTaskDelay(pdMS_TO_TICKS(100));
        esp_restart();
    } else {
        ESP_LOGW(TAG, "Unknown command: %s", command.c_str());
    }
}

std::string GetCommandStatus() {
    return "Command interface ready. Supported commands: " RESTART_COMMAND;
}

void SetCustomBLEGapHandler() {
    // GAP Event-Listener einrichten
    gap_event_listener.fn = custom_gap_event;
    gap_event_listener.arg = NULL;
    ble_gap_event_listener_register(&gap_event_listener, custom_gap_event, NULL);
}

python write_ble_characteristic.py 24:EC:4A:76:00:32 87654321-fedc-ba98-8765-4321fedcba98 RESTART