Refactor JsonWorkflowStateSerializer to improve performance

src/apps/Directory.Build.props

@@ -1,6 +1,6 @@
 <Project>
     <PropertyGroup>
-        <TargetFramework>net8.0</TargetFramework>
+        <TargetFramework>net9.0</TargetFramework>
         <LangVersion>latest</LangVersion>
         <Nullable>enable</Nullable>
         <ImplicitUsings>enable</ImplicitUsings>

src/modules/Elsa.Workflows.Api/Endpoints/WorkflowDefinitions/ImportFiles/Endpoint.cs

@@ -108,7 +108,7 @@ private async Task<int> ImportFilesAsync(IFormFileCollection files, Cancellation
 
     private async Task ImportJsonStreamAsync(Stream jsonStream, CancellationToken cancellationToken)
     {
-        var json = await new StreamReader(jsonStream).ReadToEndAsync();
+        var json = await new StreamReader(jsonStream).ReadToEndAsync(cancellationToken);
         var model = _apiSerializer.Deserialize<WorkflowDefinitionModel>(json);
         await ImportSingleWorkflowDefinitionAsync(model, cancellationToken);
     }

src/modules/Elsa.Workflows.Core/Serialization/Serializers/JsonWorkflowStateSerializer.cs

@@ -1,7 +1,5 @@
 using System.Diagnostics.CodeAnalysis;
 using System.Text.Json;
-using System.Text.Json.Serialization;
-using System.Text.Json.Serialization.Metadata;
 using Elsa.Common.Serialization;
 using Elsa.Expressions.Contracts;
 using Elsa.Workflows.Serialization.Converters;
@@ -129,29 +127,18 @@ public T Deserialize<T>(string serializedState)
     /// <inheritdoc />
     public override JsonSerializerOptions GetOptions()
     {
-        // Bypass cached options to ensure that the reference handler is always fresh.
-        return GetOptionsInternal();
-    }
-
-    /// <inheritdoc />
-    protected override void Configure(JsonSerializerOptions options)
-    {
-        var referenceHandler = new CrossScopedReferenceHandler();
-
-        options.ReferenceHandler = referenceHandler;
-        options.PropertyNamingPolicy = JsonNamingPolicy.CamelCase;
-        options.PropertyNameCaseInsensitive = true;
-        options.DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull;
+        var options = base.GetOptions();
+        return new JsonSerializerOptions(options)
+        {
+            ReferenceHandler = new CrossScopedReferenceHandler()
+        };
     }
 
     /// <inheritdoc />
     protected override void AddConverters(JsonSerializerOptions options)
     {
-        options.Converters.Add(new JsonStringEnumConverter());
         options.Converters.Add(new TypeJsonConverter(_wellKnownTypeRegistry));
-        options.Converters.Add(JsonMetadataServices.TimeSpanConverter);
         options.Converters.Add(new PolymorphicObjectConverterFactory(_wellKnownTypeRegistry));
-        options.Converters.Add(new TypeJsonConverter(_wellKnownTypeRegistry));
         options.Converters.Add(new VariableConverterFactory(_wellKnownTypeRegistry, _loggerFactory));
     }
 }

src/modules/Elsa.Workflows.Management/Services/WorkflowDefinitionImporter.cs

@@ -36,7 +36,7 @@ public async Task<ImportWorkflowResult> ImportAsync(SaveWorkflowDefinitionReques
             // Get a workflow draft version.
             var draft = !string.IsNullOrWhiteSpace(definitionId)
                 ? await _workflowDefinitionPublisher.GetDraftAsync(definitionId, VersionOptions.Latest, cancellationToken)
-                : default;
+                : null;
 
             var isNew = draft == null;