MQTTnet/Source/MQTTnet/Formatter/MqttPublishPacketFactory.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System;
using MQTTnet.Exceptions;
using MQTTnet.Packets;
using MQTTnet.Server;

namespace MQTTnet.Formatter
{
    public sealed class MqttPublishPacketFactory
    {
        public MqttPublishPacket Clone(MqttPublishPacket publishPacket)
        {
            return new MqttPublishPacket
            {
                Topic = publishPacket.Topic,
                PayloadSegment = publishPacket.PayloadSegment, 
                Retain = publishPacket.Retain,
                QualityOfServiceLevel = publishPacket.QualityOfServiceLevel,
                Dup = publishPacket.Dup,
                PacketIdentifier = publishPacket.PacketIdentifier
            };
        }

        public MqttPublishPacket Create(MqttApplicationMessage applicationMessage)
        {
            if (applicationMessage == null)
            {
                throw new ArgumentNullException(nameof(applicationMessage));
            }

            // Copy all values to their matching counterparts.
            // The not supported values in MQTT 3.1.1 are not serialized (excluded) later.
            var packet = new MqttPublishPacket
            {
                Topic = applicationMessage.Topic,
                PayloadSegment = applicationMessage.PayloadSegment, 
                QualityOfServiceLevel = applicationMessage.QualityOfServiceLevel,
                Retain = applicationMessage.Retain,
                Dup = applicationMessage.Dup,
                ContentType = applicationMessage.ContentType,
                CorrelationData = applicationMessage.CorrelationData,
                MessageExpiryInterval = applicationMessage.MessageExpiryInterval,
                PayloadFormatIndicator = applicationMessage.PayloadFormatIndicator,
                ResponseTopic = applicationMessage.ResponseTopic,
                TopicAlias = applicationMessage.TopicAlias,
                SubscriptionIdentifiers = applicationMessage.SubscriptionIdentifiers,
                UserProperties = applicationMessage.UserProperties
            };

            return packet;
        }

        public MqttPublishPacket Create(MqttConnectPacket connectPacket)
        {
            if (connectPacket == null)
            {
                throw new ArgumentNullException(nameof(connectPacket));
            }

            if (!connectPacket.WillFlag)
            {
                throw new MqttProtocolViolationException("The CONNECT packet contains no will message (WillFlag).");
            }

            ArraySegment<byte> willMessageBuffer = default;
            if (connectPacket.WillMessage?.Length > 0)
            {
                willMessageBuffer = new ArraySegment<byte>(connectPacket.WillMessage);
            }

            var packet = new MqttPublishPacket
            {
                Topic = connectPacket.WillTopic,
                PayloadSegment = willMessageBuffer,
                QualityOfServiceLevel = connectPacket.WillQoS,
                Retain = connectPacket.WillRetain,
                ContentType = connectPacket.WillContentType,
                CorrelationData = connectPacket.WillCorrelationData,
                MessageExpiryInterval = connectPacket.WillMessageExpiryInterval,
                PayloadFormatIndicator = connectPacket.WillPayloadFormatIndicator,
                ResponseTopic = connectPacket.WillResponseTopic,
                UserProperties = connectPacket.WillUserProperties
            };

            return packet;
        }

        public MqttPublishPacket Create(MqttRetainedMessageMatch retainedMessage)
        {
            if (retainedMessage == null)
            {
                throw new ArgumentNullException(nameof(retainedMessage));
            }

            var publishPacket = Create(retainedMessage.ApplicationMessage);
            publishPacket.QualityOfServiceLevel = retainedMessage.SubscriptionQualityOfServiceLevel;
            return publishPacket;
        }
    }
}