// SPDX-License-Identifier: LGPL-3.0-or-later // Copyright 2016-2025 Hristo Gochkov, Mathieu Carbou, Emil Muratov // // Shows how to trigger an async client request from a browser request and send the client response back to the browser through websocket // #include #if defined(ESP32) || defined(LIBRETINY) #include #include #elif defined(ESP8266) #include #include #elif defined(TARGET_RP2040) || defined(TARGET_RP2350) || defined(PICO_RP2040) || defined(PICO_RP2350) #include #include #endif #include #define WIFI_SSID "IoT" #define WIFI_PASSWORD "" static AsyncWebServer server(80); static AsyncWebSocketMessageHandler wsHandler; static AsyncWebSocket ws("/ws", wsHandler.eventHandler()); static const char *htmlContent PROGMEM = R"( WebSocket Tunnel Example

WebSocket Tunnel Example


    
  
  
    )";
static const size_t htmlContentLength = strlen_P(htmlContent);

void setup() {
  Serial.begin(115200);

#if SOC_WIFI_SUPPORTED || CONFIG_ESP_WIFI_REMOTE_ENABLED || LT_ARD_HAS_WIFI
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
  }
  Serial.println("Connected to WiFi!");
  Serial.println(WiFi.localIP());
#endif

  server.on("/", HTTP_GET, [](AsyncWebServerRequest *request) {
    request->send(200, "text/html", (const uint8_t *)htmlContent, htmlContentLength);
  });

  wsHandler.onMessage([](AsyncWebSocket *server, AsyncWebSocketClient *wsClient, const uint8_t *data, size_t len) {
    String url;
    String host;
    String port;
    String path;

    url.concat((const char *)data, len);

    if (!url.startsWith("http://")) {
      return;
    }

    if (!url.endsWith("/")) {
      url += "/";
    }

    // Parse the URL to extract the host and port
    int start = url.indexOf("://") + 3;
    int end = url.indexOf("/", start);
    if (end == -1) {
      end = url.length();
    }
    String hostPort = url.substring(start, end);
    int colonIndex = hostPort.indexOf(":");
    if (colonIndex != -1) {
      host = hostPort.substring(0, colonIndex);
      port = hostPort.substring(colonIndex + 1);
    } else {
      host = hostPort;
      port = "80";  // Default HTTP port
    }
    path = url.substring(end);

    Serial.printf("Host: %s\n", host.c_str());
    Serial.printf("Port: %s\n", port.c_str());
    Serial.printf("Path: %s\n", path.c_str());

    // Ensure client does not get deleted while the websocket holds a reference to it
    std::shared_ptr *safeAsyncClient = new std::shared_ptr(std::make_shared());
    AsyncClient *asyncClient = safeAsyncClient->get();

    asyncClient->onDisconnect([safeAsyncClient](void *arg, AsyncClient *client) {
      Serial.printf("Tunnel disconnected!\n");
      delete safeAsyncClient;
    });

    // register a callback when an error occurs
    // note: onDisconnect also called on error
    asyncClient->onError([](void *arg, AsyncClient *client, int8_t error) {
      Serial.printf("Tunnel error: %s\n", client->errorToString(error));
    });

    // register a callback when data arrives, to accumulate it
    asyncClient->onPacket(
      [safeAsyncClient](void *arg, AsyncClient *, struct pbuf *pb) {
        std::shared_ptr safeAsyncClientRef = *safeAsyncClient;  // add a reference
        AsyncWebSocketClient *wsClient = (AsyncWebSocketClient *)arg;
        Serial.printf("Tunnel received %u bytes\n", pb->len);
        AsyncWebSocketSharedBuffer wsBuffer =
          AsyncWebSocketSharedBuffer(new std::vector((uint8_t *)pb->payload, (uint8_t *)pb->payload + pb->len), [=](std::vector *bufptr) {
            delete bufptr;
            Serial.printf("ACK %u bytes\n", pb->len);
            safeAsyncClientRef->ackPacket(pb);
          });
        Serial.printf("Tunnel sending %u bytes\n", wsBuffer->size());
        Serial.printf("%.*s\n", (int)wsBuffer->size(), wsBuffer->data());
        wsClient->binary(std::move(wsBuffer));
      },
      wsClient
    );

    asyncClient->onConnect([=](void *arg, AsyncClient *client) {
      Serial.printf("Tunnel connected!\n");

      client->write("GET ");
      client->write(path.c_str());
      client->write(" HTTP/1.1\r\n");
      client->write("Host: ");
      client->write(host.c_str());
      client->write(":");
      client->write(port.c_str());
      client->write("\r\n");
      client->write("User-Agent: ESP32\r\n");
      client->write("Accept: */*\r\n");
      client->write("Connection: close\r\n");
      client->write("\r\n");
    });

    Serial.printf("Fetching: http://%s:%s%s\n", host.c_str(), port.c_str(), path.c_str());

    if (!asyncClient->connect(host.c_str(), port.toInt())) {
      Serial.printf("Failed to open tunnel!\n");
      delete safeAsyncClient;
    }
  });

  wsHandler.onConnect([](AsyncWebSocket *server, AsyncWebSocketClient *client) {
    Serial.printf("Client %" PRIu32 " connected\n", client->id());
    client->binary("WebSocket connected!");
  });

  wsHandler.onDisconnect([](AsyncWebSocket *server, uint32_t clientId) {
    Serial.printf("Client %" PRIu32 " disconnected\n", clientId);
  });

  server.addHandler(&ws);
  server.begin();
  Serial.println("Server started!");
}

static uint32_t lastHeap = 0;

void loop() {
  ws.cleanupClients(2);

#ifdef ESP32
  uint32_t now = millis();
  if (now - lastHeap >= 2000) {
    Serial.printf("Uptime: %3lu s, Free heap: %" PRIu32 "\n", millis() / 1000, ESP.getFreeHeap());
    lastHeap = now;
  }
#endif

  delay(500);
}