static byte EncodeSubscribePacket(MqttSubscribePacket packet, IMqttPacketWriter packetWriter)
{
if (packet.TopicFilters?.Any() != true)
{
throw new MqttProtocolViolationException("At least one topic filter must be set [MQTT-3.8.3-3].");
}
ThrowIfPacketIdentifierIsInvalid(packet.PacketIdentifier, packet);
packetWriter.Write(packet.PacketIdentifier);
var propertiesWriter = new MqttV500PropertiesWriter();
if (packet.Properties != null)
{
propertiesWriter.WriteSubscriptionIdentifier(packet.Properties.SubscriptionIdentifier);
propertiesWriter.WriteUserProperties(packet.Properties.UserProperties);
}
propertiesWriter.WriteTo(packetWriter);
if (packet.TopicFilters?.Count > 0)
{
foreach (var topicFilter in packet.TopicFilters)
{
packetWriter.WriteWithLengthPrefix(topicFilter.Topic);
var options = (byte)topicFilter.QualityOfServiceLevel;
if (topicFilter.NoLocal == true)
{
options |= 1 << 2;
}
if (topicFilter.RetainAsPublished == true)
{
options |= 1 << 3;
}
if (topicFilter.RetainHandling.HasValue)
{
options |= (byte)((byte)topicFilter.RetainHandling.Value << 4);
}
packetWriter.Write(options);
}
}
return(MqttPacketWriter.BuildFixedHeader(MqttControlPacketType.Subscribe, 0x02));
}
