Method _sendPing

index.js:501–531

* Sends a heartbeat ping to the device * @private

()

   * @private
   */
  async _sendPing() {
    debug(`Pinging ${this.device.ip}`);

    // Create byte buffer
    const buffer = this.device.parser.encode({
      data: Buffer.allocUnsafe(0),
      commandByte: CommandType.HEART_BEAT,
      sequenceN: ++this._currentSequenceN
    });

    // Check for response
    const now = new Date();

    if (this._pingPongTimeout === null) {
      // If we do not expect a pong from a former ping, we need to set a timeout
      this._pingPongTimeout = setTimeout(() => {
        if (this._lastPingAt < now) {
          this.disconnect();
        }
      }, this._responseTimeout * 1000);
    } else {
      debug('There was no response to the last ping.');
    }

    // Send ping
    this.client.write(buffer);
    if (this.globalOptions.issueRefreshOnPing) {
      this.refresh();
      this.get();
    }
  }

  /**
   * Create a deferred promise that resolves as soon as the connection is established.