Serialization fixes.

src/Squidex/Areas/Api/Controllers/MyJsonInheritanceConverter.cs

@@ -8,42 +8,85 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Reflection;
+using System.Runtime.Serialization;
+using Newtonsoft.Json.Linq;
 using NJsonSchema.Converters;
+using Squidex.Infrastructure;
+
+#pragma warning disable RECS0108 // Warns about static fields in generic types
 
 namespace Squidex.Areas.Api.Controllers
 {
-    public class MyJsonInheritanceConverter : JsonInheritanceConverter
+    public class MyJsonInheritanceConverter<T> : JsonInheritanceConverter
     {
-        private readonly IDictionary<string, Type> mapping;
-        private readonly Type baseType;
+        private static readonly Dictionary<string, Type> DefaultMapping = new Dictionary<string, Type>();
+        private readonly IReadOnlyDictionary<string, Type> maping;
 
-        public MyJsonInheritanceConverter(string discriminator, Type baseType)
-            : base(baseType, discriminator)
+        static MyJsonInheritanceConverter()
         {
-            this.baseType = baseType;
-        }
+            var baseName = typeof(T).Name;
 
-        public MyJsonInheritanceConverter(string discriminator, Type baseType, IDictionary<string, Type> mapping)
-            : this(discriminator, baseType)
-        {
-            this.mapping = mapping;
-        }
+            void AddType(Type type)
+            {
+                var discriminator = type.Name;
 
-        public override string GetDiscriminatorValue(Type type)
-        {
-            var result = type.Name;
+                if (discriminator.EndsWith(baseName, StringComparison.CurrentCulture))
+                {
+                    discriminator = discriminator.Substring(0, discriminator.Length - baseName.Length);
+                }
 
-            if (baseType != null)
-            {
-                var baseName = baseType.Name;
+                DefaultMapping[discriminator] = type;
+            }
 
-                if (result.EndsWith(baseName, StringComparison.CurrentCulture))
+            foreach (var attribute in typeof(T).GetCustomAttributes<KnownTypeAttribute>())
+            {
+                if (attribute.Type != null)
+                {
+                    if (!attribute.Type.IsAbstract)
+                    {
+                        AddType(attribute.Type);
+                    }
+                }
+                else if (!string.IsNullOrWhiteSpace(attribute.MethodName))
                 {
-                    return result.Substring(0, result.Length - baseName.Length);
+                    var method = typeof(T).GetMethod(attribute.MethodName);
+
+                    if (method != null && method.IsStatic)
+                    {
+                        var types = (IEnumerable<Type>)method.Invoke(null, new object[0]);
+
+                        foreach (var type in types)
+                        {
+                            if (!type.IsAbstract)
+                            {
+                                AddType(type);
+                            }
+                        }
+                    }
                 }
             }
+        }
+
+        public MyJsonInheritanceConverter(string discriminator)
+            : this(discriminator, DefaultMapping)
+        {
+        }
+
+        public MyJsonInheritanceConverter(string discriminator, IReadOnlyDictionary<string, Type> mapping)
+            : base(typeof(T), discriminator)
+        {
+            maping = mapping;
+        }
 
-            return mapping?.FirstOrDefault(x => x.Value == type).Key ?? result;
+        protected override Type GetDiscriminatorType(JObject jObject, Type objectType, string discriminatorValue)
+        {
+            return maping.GetOrDefault(discriminatorValue) ?? throw new InvalidOperationException($"Could not find subtype of '{objectType.Name}' with discriminator '{discriminatorValue}'.");
+        }
+
+        public override string GetDiscriminatorValue(Type type)
+        {
+            return maping.FirstOrDefault(x => x.Value == type).Key ?? type.Name;
         }
     }
 }

src/Squidex/Areas/Api/Controllers/Rules/Models/CreateRuleDto.cs

@@ -24,7 +24,7 @@ namespace Squidex.Areas.Api.Controllers.Rules.Models
         /// The action properties.
         /// </summary>
         [Required]
-        [JsonConverter(typeof(RuleActionSerializer))]
+        [JsonConverter(typeof(RuleActionConverter))]
         public RuleAction Action { get; set; }
 
         public CreateRule ToCommand()

src/Squidex/Areas/Api/Controllers/Rules/Models/RuleActionSerializer.cs → src/Squidex/Areas/Api/Controllers/Rules/Models/RuleActionConverter.cs

@@ -5,16 +5,20 @@
 //  All rights reserved. Licensed under the MIT license.
 // ==========================================================================
 
+using System;
+using System.Collections.Generic;
 using System.Linq;
 using Squidex.Domain.Apps.Core.Rules;
 using Squidex.Extensions.Actions;
 
 namespace Squidex.Areas.Api.Controllers.Rules.Models
 {
-    public sealed class RuleActionSerializer : MyJsonInheritanceConverter
+    public sealed class RuleActionConverter : MyJsonInheritanceConverter<RuleAction>
     {
-        public RuleActionSerializer()
-            : base("actionType", typeof(RuleAction), RuleElementRegistry.Actions.ToDictionary(x => x.Key, x => x.Value.Type))
+        private static readonly Dictionary<string, Type> Mapping = RuleElementRegistry.Actions.ToDictionary(x => x.Key, x => x.Value.Type);
+
+        public RuleActionConverter()
+            : base("actionType", Mapping)
         {
         }
     }

src/Squidex/Areas/Api/Controllers/Rules/Models/RuleActionProcessor.cs

@@ -26,17 +26,14 @@ namespace Squidex.Areas.Api.Controllers.Rules.Models
 
                 if (schema != null)
                 {
-                    var discriminator = new OpenApiDiscriminator
+                    schema.DiscriminatorObject = new OpenApiDiscriminator
                     {
-                        JsonInheritanceConverter = new MyJsonInheritanceConverter("actionType", typeof(RuleAction)),
-                        PropertyName = "actionType"
+                        JsonInheritanceConverter = new RuleActionConverter(), PropertyName = "actionType"
                     };
 
-                    schema.DiscriminatorObject = discriminator;
                     schema.Properties["actionType"] = new JsonProperty
                     {
-                        Type = JsonObjectType.String,
-                        IsRequired = true
+                        Type = JsonObjectType.String, IsRequired = true
                     };
 
                     foreach (var derived in RuleElementRegistry.Actions)

src/Squidex/Areas/Api/Controllers/Rules/Models/RuleDto.cs

@@ -67,7 +67,7 @@ namespace Squidex.Areas.Api.Controllers.Rules.Models
         /// The action properties.
         /// </summary>
         [Required]
-        [JsonConverter(typeof(RuleActionSerializer))]
+        [JsonConverter(typeof(RuleActionConverter))]
         public RuleAction Action { get; set; }
 
         public static RuleDto FromRule(IRuleEntity rule)

src/Squidex/Areas/Api/Controllers/Rules/Models/RuleTriggerDto.cs

@@ -13,7 +13,7 @@ using Squidex.Domain.Apps.Core.Rules;
 
 namespace Squidex.Areas.Api.Controllers.Rules.Models
 {
-    [JsonConverter(typeof(MyJsonInheritanceConverter), "triggerType", typeof(RuleTriggerDto))]
+    [JsonConverter(typeof(MyJsonInheritanceConverter<RuleTriggerDto>), "triggerType")]
     [KnownType(nameof(Subtypes))]
     public abstract class RuleTriggerDto
     {

src/Squidex/Areas/Api/Controllers/Rules/Models/UpdateRuleDto.cs

@@ -22,7 +22,7 @@ namespace Squidex.Areas.Api.Controllers.Rules.Models
         /// <summary>
         /// The action properties.
         /// </summary>
-        [JsonConverter(typeof(RuleActionSerializer))]
+        [JsonConverter(typeof(RuleActionConverter))]
         public RuleAction Action { get; set; }
 
         public UpdateRule ToCommand(Guid id)

src/Squidex/Areas/Api/Controllers/Schemas/Models/FieldPropertiesDto.cs

@@ -14,7 +14,7 @@ using Squidex.Domain.Apps.Core.Schemas;
 
 namespace Squidex.Areas.Api.Controllers.Schemas.Models
 {
-    [JsonConverter(typeof(MyJsonInheritanceConverter), "fieldType", typeof(FieldPropertiesDto))]
+    [JsonConverter(typeof(MyJsonInheritanceConverter<FieldPropertiesDto>), "fieldType")]
     [KnownType(nameof(Subtypes))]
     public abstract class FieldPropertiesDto
     {