fix: make optional properties of bindings nullable

src/LEGO.AsyncAPI.Readers/ParseNodes/ParseNode.cs

@@ -96,21 +96,41 @@ public virtual string GetScalarValue()
             throw new AsyncApiReaderException("Cannot create a scalar value from this type of node.", this.Context);
         }
 
+        public virtual string GetScalarValueOrDefault(string defaultValue)
+        {
+            throw new AsyncApiReaderException("Cannot create a scalar value from this type of node.", this.Context);
+        }
+
         public virtual bool GetBooleanValue()
         {
             throw new AsyncApiReaderException("Cannot create a scalar value from this type of node.", this.Context);
         }
 
+        public virtual bool? GetBooleanValueOrDefault(bool? defaultValue)
+        {
+            throw new AsyncApiReaderException("Cannot create a scalar value from this type of node.", this.Context);
+        }
+
         public virtual int GetIntegerValue()
         {
             throw new AsyncApiReaderException("Cannot create a scalar value from this type of node.", this.Context);
         }
 
+        public virtual int? GetIntegerValueOrDefault(int? defaultValue)
+        {
+            throw new AsyncApiReaderException("Cannot create a scalar value from this type of node.", this.Context);
+        }
+
         public virtual long GetLongValue()
         {
             throw new AsyncApiReaderException("Cannot create a scalar value from this type of node.", this.Context);
         }
 
+        public virtual long? GetLongValueOrDefault(long? defaultValue)
+        {
+            throw new AsyncApiReaderException("Cannot create a scalar value from this type of node.", this.Context);
+        }
+
         public virtual List<IAsyncApiAny> CreateListOfAny()
         {
             throw new AsyncApiReaderException("Cannot create a list from this type of node.", this.Context);

src/LEGO.AsyncAPI.Readers/ParseNodes/ValueNode.cs

@@ -29,6 +29,16 @@ public override string GetScalarValue()
             return this.node.Value;
         }
 
+        public override string GetScalarValueOrDefault(string defaultValue)
+        {
+            if (this.node.Value is not null)
+            {
+                return this.node.Value;
+            }
+
+            return defaultValue;
+        }
+
         public override int GetIntegerValue()
         {
             if (int.TryParse(this.node.Value, out int value))
@@ -39,6 +49,16 @@ public override int GetIntegerValue()
             throw new AsyncApiReaderException("Value could not parse to integer", this.node);
         }
 
+        public override int? GetIntegerValueOrDefault(int? defaultValue)
+        {
+            if (int.TryParse(this.node.Value, out int value))
+            {
+                return value;
+            }
+
+            return defaultValue;
+        }
+
         public override long GetLongValue()
         {
             if (long.TryParse(this.node.Value, out long value))
@@ -49,6 +69,16 @@ public override long GetLongValue()
             throw new AsyncApiReaderException("Value could not parse to long", this.node);
         }
 
+        public override long? GetLongValueOrDefault(long? defaultValue)
+        {
+            if (long.TryParse(this.node.Value, out long value))
+            {
+                return value;
+            }
+
+            return defaultValue;
+        }
+
         public override bool GetBooleanValue()
         {
             if (bool.TryParse(this.node.Value, out bool value))
@@ -59,6 +89,16 @@ public override bool GetBooleanValue()
             throw new AsyncApiReaderException("Value could not parse to bool", this.node);
         }
 
+        public override bool? GetBooleanValueOrDefault(bool? defaultValue)
+        {
+            if (bool.TryParse(this.node.Value, out bool value))
+            {
+                return value;
+            }
+
+            return defaultValue;
+        }
+
         public override IAsyncApiAny CreateAny()
         {
             var value = this.GetScalarValue();

src/LEGO.AsyncAPI.Readers/V2/AsyncApiDocumentDeserializer.cs

@@ -10,7 +10,7 @@ internal static partial class AsyncApiV2Deserializer
     {
         private static FixedFieldMap<AsyncApiDocument> asyncApiFixedFields = new()
         {
-            { "asyncapi", (a, n) => { a.Asyncapi = "2.5.0"; } },
+            { "asyncapi", (a, n) => { a.Asyncapi = "2.6.0"; } },
             { "id", (a, n) => a.Id = n.GetScalarValue() },
             { "info", (a, n) => a.Info = LoadInfo(n) },
             { "servers", (a, n) => a.Servers = n.CreateMap(LoadServer) },

src/LEGO.AsyncAPI/LEGO.AsyncAPI.csproj

@@ -11,6 +11,7 @@
 	<AssemblyName>LEGO.AsyncAPI</AssemblyName>
 	<RootNamespace>LEGO.AsyncAPI</RootNamespace>
 	<RepositoryUrl>https://github.com/LEGO/AsyncAPI.NET</RepositoryUrl>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

src/LEGO.AsyncAPI/Models/AsyncApiDocument.cs

@@ -76,7 +76,7 @@ public void SerializeV2(IAsyncApiWriter writer)
             writer.WriteStartObject();
 
             // asyncApi
-            writer.WriteRequiredProperty(AsyncApiConstants.AsyncApi, "2.5.0");
+            writer.WriteRequiredProperty(AsyncApiConstants.AsyncApi, "2.6.0");
 
             // info
             writer.WriteRequiredObject(AsyncApiConstants.Info, this.Info, (w, i) => i.SerializeV2(w));

src/LEGO.AsyncAPI/Models/Bindings/Http/HttpMessageBinding.cs

@@ -16,7 +16,7 @@ public class HttpMessageBinding : IMessageBinding
         /// <summary>
         /// A Schema object containing the definitions for HTTP-specific headers. This schema MUST be of type object and have a properties key.
         /// </summary>
-        public AsyncApiSchema Headers { get; set; }
+        public AsyncApiSchema? Headers { get; set; }
 
         /// <summary>
         /// The version of this binding. If omitted, "latest" MUST be assumed.

src/LEGO.AsyncAPI/Models/Bindings/Http/HttpOperationBinding.cs

@@ -20,12 +20,12 @@ public class HttpOperationBinding : IOperationBinding
         /// <summary>
         /// When type is request, this is the HTTP method, otherwise it MUST be ignored. Its value MUST be one of GET, POST, PUT, PATCH, DELETE, HEAD, OPTIONS, CONNECT, and TRACE.
         /// </summary>
-        public string Method { get; set; }
+        public string? Method { get; set; }
 
         /// <summary>
         /// A Schema object containing the definitions for each query parameter. This schema MUST be of type object and have a properties key.
         /// </summary>
-        public AsyncApiSchema Query { get; set; }
+        public AsyncApiSchema? Query { get; set; }
 
         /// <summary>
         /// The version of this binding. If omitted, "latest" MUST be assumed.

src/LEGO.AsyncAPI/Models/Bindings/Kafka/KafkaChannelBinding.cs

@@ -15,17 +15,17 @@ public class KafkaChannelBinding : IChannelBinding
         /// <summary>
         /// Kafka topic name if different from channel name.
         /// </summary>
-        public string Topic { get; set; }
+        public string? Topic { get; set; }
 
         /// <summary>
         /// Number of partitions configured on this topic (useful to know how many parallel consumers you may run).
         /// </summary>
-        public int Partitions { get; set; }
+        public int? Partitions { get; set; }
 
         /// <summary>
         /// Number of replicas configured on this topic.
         /// </summary>
-        public int Replicas { get; set; }
+        public int? Replicas { get; set; }
 
         /// <summary>
         /// Topic configuration properties that are relevant for the API.

src/LEGO.AsyncAPI/Models/Bindings/Kafka/KafkaMessageBinding.cs

@@ -15,22 +15,22 @@ public class KafkaMessageBinding : IMessageBinding
         /// <summary>
         /// The message key. NOTE: You can also use the <a href="https://www.asyncapi.com/docs/reference/specification/v2.4.0#referenceObject">reference object</a> way.
         /// </summary>
-        public AsyncApiSchema Key { get; set; }
+        public AsyncApiSchema? Key { get; set; }
 
         /// <summary>
         /// If a Schema Registry is used when performing this operation, tells where the id of schema is stored (e.g. header or payload).
         /// </summary>
-        public string SchemaIdLocation { get; set; }
+        public string? SchemaIdLocation { get; set; }
 
         /// <summary>
         /// Number of bytes or vendor specific values when schema id is encoded in payload (e.g confluent/ apicurio-legacy / apicurio-new).
         /// </summary>
-        public string SchemaIdPayloadEncoding { get; set; }
+        public string? SchemaIdPayloadEncoding { get; set; }
 
         /// <summary>
         /// Freeform string for any naming strategy class to use. Clients should default to the vendor default if not supplied.
         /// </summary>
-        public string SchemaLookupStrategy { get; set; }
+        public string? SchemaLookupStrategy { get; set; }
 
         /// <summary>
         /// The version of this binding. If omitted, "latest" MUST be assumed.

src/LEGO.AsyncAPI/Models/Bindings/Kafka/KafkaOperationBinding.cs

@@ -15,12 +15,12 @@ public class KafkaOperationBinding : IOperationBinding
         /// <summary>
         /// Id of the consumer group.
         /// </summary>
-        public AsyncApiSchema GroupId { get; set; }
+        public AsyncApiSchema? GroupId { get; set; }
 
         /// <summary>
         /// Id of the consumer inside a consumer group.
         /// </summary>
-        public AsyncApiSchema ClientId { get; set; }
+        public AsyncApiSchema? ClientId { get; set; }
 
         /// <summary>
         /// The version of this binding. If omitted, "latest" MUST be assumed.

src/LEGO.AsyncAPI/Models/Bindings/Kafka/KafkaServerBinding.cs

@@ -15,12 +15,12 @@ public class KafkaServerBinding : IServerBinding
         /// <summary>
         /// API URL for the Schema Registry used when producing Kafka messages (if a Schema Registry was used)
         /// </summary>
-        public string SchemaRegistryUrl { get; set; }
+        public string? SchemaRegistryUrl { get; set; }
 
         /// <summary>
         /// The vendor of Schema Registry and Kafka serdes library that should be used (e.g. apicurio, confluent, ibm, or karapace)
         /// </summary>
-        public string SchemaRegistryVendor { get; set; }
+        public string? SchemaRegistryVendor { get; set; }
 
         /// <summary>
         /// The version of this binding.

src/LEGO.AsyncAPI/Models/Bindings/Kafka/TopicConfigurationObject.cs

@@ -12,27 +12,27 @@ public class TopicConfigurationObject : IAsyncApiElement
         /// <summary>
         /// The cleanup.policy configuration option.
         /// </summary>
-        public List<string> CleanupPolicy { get; set; }
+        public List<string>? CleanupPolicy { get; set; }
 
         /// <summary>
         /// The retention.ms configuration option.
         /// </summary>
-        public int RetentionMiliseconds { get; set; }
+        public int? RetentionMiliseconds { get; set; }
 
         /// <summary>
         /// The retention.bytes configuration option.
         /// </summary>
-        public int RetentionBytes { get; set; }
+        public int? RetentionBytes { get; set; }
 
         /// <summary>
         /// The delete.retention.ms configuration option.
         /// </summary>
-        public int DeleteRetentionMiliseconds { get; set; }
+        public int? DeleteRetentionMiliseconds { get; set; }
 
         /// <summary>
         /// The max.message.bytes configuration option.
         /// </summary>
-        public int MaxMessageBytes { get; set; }
+        public int? MaxMessageBytes { get; set; }
 
         public void Serialize(IAsyncApiWriter writer)
         {

src/LEGO.AsyncAPI/Models/Bindings/Pulsar/PulsarChannelBinding.cs

@@ -25,7 +25,7 @@ public class PulsarChannelBinding : IChannelBinding
         /// <summary>
         /// Topic compaction threshold given in bytes.
         /// </summary>
-        public int Compaction { get; set; }
+        public int? Compaction { get; set; }
 
         /// <summary>
         /// A list of clusters the topic is replicated to.
@@ -40,12 +40,12 @@ public class PulsarChannelBinding : IChannelBinding
         /// <summary>
         /// Message Time-to-live in seconds. 
         /// </summary>
-        public int TTL { get; set; }
+        public int? TTL { get; set; }
 
         /// <summary>
         /// When Message deduplication is enabled, it ensures that each message produced on Pulsar topics is persisted to disk only once.
         /// </summary>
-        public bool Deduplication { get; set; }
+        public bool? Deduplication { get; set; }
 
         /// <summary>
         /// The version of this binding.

src/LEGO.AsyncAPI/Models/Bindings/Pulsar/PulsarServerBinding.cs

@@ -15,7 +15,7 @@ public class PulsarServerBinding : IServerBinding
         /// <summary>
         /// The pulsar tenant. If omitted, "public" must be assumed.
         /// </summary>
-        public string Tenant { get; set; }
+        public string? Tenant { get; set; }
 
         /// <summary>
         /// The version of this binding.

src/LEGO.AsyncAPI/Models/Bindings/WebSockets/WebSocketsChannelBinding.cs

@@ -12,17 +12,17 @@ public class WebSocketsChannelBinding : IChannelBinding
         /// <summary>
         /// The HTTP method t use when establishing the connection. Its value MUST be either 'GET' or 'POST'.
         /// </summary>
-        public string Method { get; set; }
+        public string? Method { get; set; }
 
         /// <summary>
         /// A Schema object containing the definitions for each query parameter. This schema MUST be of type 'object' and have a 'properties' key.
         /// </summary>
-        public AsyncApiSchema Query { get; set; }
+        public AsyncApiSchema? Query { get; set; }
 
         /// <summary>
         /// A Schema object containing the definitions of the HTTP headers to use when establishing the connection. This schma MUST be of type 'object' and have a 'properties' key.
         /// </summary>
-        public AsyncApiSchema Headers { get; set; }
+        public AsyncApiSchema? Headers { get; set; }
 
         public string BindingVersion { get; set; }
 

test/LEGO.AsyncAPI.Tests/AsyncApiDocumentV2Tests.cs

@@ -24,10 +24,10 @@ public void AsyncApiDocument_WithStreetLightsExample_SerializesAndDeserializes()
         {
             // Arrange
             var expected =
-@"asyncapi: '2.5.0'
+@"asyncapi: '2.6.0'
 info:
   title: Streetlights Kafka API
-  version: 1.0.0
+  version: '1.0.0'
   description: The Smartylighting Streetlights API allows you to remotely manage the city lights.
   license:
     name: Apache 2.0
@@ -699,7 +699,7 @@ public void AsyncApiDocument_WithStreetLightsExample_SerializesAndDeserializes()
         public void SerializeV2_WithFullSpec_Serializes()
         {
             var expected =
-                @"asyncapi: '2.5.0'
+                @"asyncapi: '2.6.0'
 info:
   title: apiTitle
   version: apiVersion
@@ -1129,7 +1129,7 @@ public void SerializeV2_WithFullSpec_Serializes()
         [Test]
         public void Serializev2_WithBindings_Serializes()
         {
-            var expected = @"asyncapi: '2.5.0'
+            var expected = @"asyncapi: '2.6.0'
 info:
   description: test description
 servers: