Add and configure custom MongoDB serializers

Introduced MongoDB serializers for various types, including `FlowScope`, to support custom serialization needs. Registered the serializers during application startup via a hosted service, ensuring seamless integration with MongoDB operations.

Author: sfmskywalker

Directory.Build.props

@@ -1,6 +1,6 @@
 <Project>
     <PropertyGroup>
-        <UseProjectReferences>false</UseProjectReferences>
+        <UseProjectReferences>true</UseProjectReferences>
     </PropertyGroup>
     <PropertyGroup>
         <Authors>Elsa Workflows Community</Authors>

src/modules/persistence/Elsa.Persistence.EFCore/Modules/Runtime/WorkflowExecutionLogStore.cs

@@ -103,5 +103,4 @@ private bool ShouldSerializePayload(WorkflowExecutionLogRecord source)
     }
 
     private static IQueryable<WorkflowExecutionLogRecord> Filter(IQueryable<WorkflowExecutionLogRecord> queryable, WorkflowExecutionLogRecordFilter filter) => filter.Apply(queryable);
-}
-}
+}

src/modules/persistence/Elsa.Persistence.MongoDb/Features/MongoDbFeature.cs

@@ -1,20 +1,16 @@
-using System.Text.Json;
-using System.Text.Json.Nodes;
 using Elsa.Features.Abstractions;
 using Elsa.Features.Services;
 using Elsa.KeyValues.Entities;
 using Elsa.Persistence.MongoDb.Contracts;
+using Elsa.Persistence.MongoDb.HostedServices;
 using Elsa.Persistence.MongoDb.NamingStrategies;
 using Elsa.Persistence.MongoDb.Options;
-using Elsa.Persistence.MongoDb.Serializers;
-using Elsa.Workflows.Memory;
+using Elsa.Workflows.Activities.Flowchart.Models;
 using Elsa.Workflows.Runtime.Entities;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
 using Microsoft.Extensions.Options;
-using MongoDB.Bson;
 using MongoDB.Bson.Serialization;
-using MongoDB.Bson.Serialization.Serializers;
 using MongoDB.Driver;
 
 namespace Elsa.Persistence.MongoDb.Features;

src/modules/persistence/Elsa.Persistence.MongoDb/HostedServices/ConfigureMongoDbSerializers.cs

@@ -0,0 +1,43 @@
+using System.Text.Json;
+using System.Text.Json.Nodes;
+using Elsa.Persistence.MongoDb.Serializers;
+using Elsa.Workflows;
+using Elsa.Workflows.Activities.Flowchart.Models;
+using Elsa.Workflows.Memory;
+using JetBrains.Annotations;
+using Microsoft.Extensions.Hosting;
+using MongoDB.Bson.Serialization.Serializers;
+using static MongoDB.Bson.Serialization.BsonSerializer;
+
+namespace Elsa.Persistence.MongoDb.HostedServices;
+
+/// <summary>
+/// A hosted service that configures and registers custom MongoDB serializers for various types.
+/// </summary>
+/// <remarks>
+/// This class implements <see cref="IHostedService"/> and is responsible for registering serializers to handle
+/// specific types such as <see cref="object"/>, <see cref="Type"/>, <see cref="Variable"/>, <see cref="Version"/>,
+/// <see cref="JsonElement"/>, <see cref="JsonNode"/>, and <see cref="FlowScope"/>.
+/// It uses helper methods to register these serializers during the application's startup process.
+/// </remarks>
+[UsedImplicitly]
+public class ConfigureMongoDbSerializers(IPayloadSerializer payloadSerializer) : IHostedService
+{
+    public Task StartAsync(CancellationToken cancellationToken)
+    {
+        TryRegisterSerializer(typeof(object), new PolymorphicSerializer());
+        TryRegisterSerializer(typeof(Type), new TypeSerializer());
+        TryRegisterSerializer(typeof(Variable), new VariableSerializer());
+        TryRegisterSerializer(typeof(Version), new VersionSerializer());
+        TryRegisterSerializer(typeof(JsonElement), new JsonElementSerializer());
+        TryRegisterSerializer(typeof(JsonNode), new JsonNodeBsonConverter());
+        TryRegisterSerializer(typeof(FlowScope), new FlowScopeSerializer(payloadSerializer));
+
+        return Task.CompletedTask;
+    }
+
+    public Task StopAsync(CancellationToken cancellationToken)
+    {
+        return Task.CompletedTask;
+    }
+}

src/modules/persistence/Elsa.Persistence.MongoDb/Modules/Management/WorkflowInstanceStore.cs

@@ -8,6 +8,7 @@
 using Elsa.Workflows.Management.Filters;
 using Elsa.Workflows.Management.Models;
 using JetBrains.Annotations;
+using Microsoft.Extensions.Logging;
 using MongoDB.Driver;
 using MongoDB.Driver.Linq;
 using Open.Linq.AsyncExtensions;

src/modules/persistence/Elsa.Persistence.MongoDb/Serializers/FlowScopeSerializer.cs

@@ -0,0 +1,52 @@
+using Elsa.Workflows;
+using Elsa.Workflows.Activities.Flowchart.Models;
+using MongoDB.Bson;
+using MongoDB.Bson.Serialization;
+
+namespace Elsa.Persistence.MongoDb.Serializers;
+
+/// <summary>
+/// Serializes a <see cref="FlowScope"/>.
+/// </summary>
+public class FlowScopeSerializer(IPayloadSerializer payloadSerializer) : IBsonSerializer<FlowScope?>
+{
+    /// <inheritdoc />
+    public Type ValueType => typeof(FlowScope);
+
+    void IBsonSerializer.Serialize(BsonSerializationContext context, BsonSerializationArgs args, object value) => Serialize(context, args, (FlowScope)value);
+    object IBsonSerializer.Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args) => Deserialize(context, args);
+
+    /// <inheritdoc />
+    public void Serialize(BsonSerializationContext context, BsonSerializationArgs args, FlowScope? value)
+    {
+        if (value is null)
+            context.Writer.WriteNull();
+        else
+        {
+            var json = payloadSerializer.Serialize(value);
+            context.Writer.WriteString(json);
+        }
+    }
+
+    /// <inheritdoc />
+    public FlowScope Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
+    {
+        var reader = context.Reader;
+        var bsonType = reader.GetCurrentBsonType();
+
+        if (bsonType == BsonType.Null)
+        {
+            reader.ReadNull();
+            return new();
+        }
+        
+        if(bsonType == BsonType.String)
+        {
+            var json = context.Reader.ReadString();
+
+            return string.IsNullOrEmpty(json) ? new() : payloadSerializer.Deserialize<FlowScope>(json);
+        }
+
+        return new();
+    }
+}