MQTTnet/Source/MQTTnet/Client/Options/MqttClientOptionsValidator.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 System.Linq;
using MQTTnet.Formatter;
using MQTTnet.Protocol;

namespace MQTTnet.Client
{
    public static class MqttClientOptionsValidator
    {
        public static void ThrowIfNotSupported(MqttClientOptions options)
        {
            if (options == null)
            {
                throw new ArgumentNullException(nameof(options));
            }

            if (options.ProtocolVersion == MqttProtocolVersion.V500)
            {
                // Everything is supported.
                return;
            }
            
            if (options.WillContentType?.Any() == true)
            {
                Throw(nameof(options.WillContentType));
            }

            if (options.UserProperties?.Any() == true)
            {
                Throw(nameof(options.UserProperties));
            }

            if (options.RequestProblemInformation)
            {
                // Since this value is a boolean and true by default, validation would
                // require a nullable boolean.
                //Throw(nameof(options.RequestProblemInformation));
            }

            if (options.RequestResponseInformation)
            {
                Throw(nameof(options.RequestResponseInformation));
            }

            if (options.ReceiveMaximum > 0)
            {
                Throw(nameof(options.ReceiveMaximum));
            }
            
            if (options.MaximumPacketSize > 0)
            {
                Throw(nameof(options.MaximumPacketSize));
            }

            // Authentication relevant properties.
            
            if (options.AuthenticationData?.Any() == true)
            {
                Throw(nameof(options.AuthenticationData));
            }

            if (options.AuthenticationMethod?.Any() == true)
            {
                Throw(nameof(options.AuthenticationMethod));
            }

            // Will relevant properties.
            
            if (options.WillPayloadFormatIndicator != MqttPayloadFormatIndicator.Unspecified)
            {
                Throw(nameof(options.WillPayloadFormatIndicator));
            }

            if (options.WillContentType?.Any() == true)
            {
                Throw(nameof(options.WillContentType));
            }

            if (options.WillCorrelationData?.Any() == true)
            {
                Throw(nameof(options.WillCorrelationData));
            }
            
            if (options.WillResponseTopic?.Any() == true)
            {
                Throw(nameof(options.WillResponseTopic));
            }
            
            if (options.WillDelayInterval > 0)
            {
                Throw(nameof(options.WillDelayInterval));
            }
            
            if (options.WillMessageExpiryInterval > 0)
            {
                Throw(nameof(options.WillMessageExpiryInterval));
            }
            
            if (options.WillUserProperties?.Any() == true)
            {
                Throw(nameof(options.WillUserProperties));
            }
        }

        static void Throw(string featureName)
        {
            throw new NotSupportedException($"Feature {featureName} requires MQTT version 5.0.0.");
        }
    }
}