System.Text.Json support.

src/Disqord.Bot/Commands/Implementation/Application/ExecutionSteps/Slash/BindOptions.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Threading.Tasks;
+using Disqord.Serialization.Json;
 using Qmmands;
 using Qommon;
 
@@ -84,15 +85,17 @@ static IReadOnlyDictionary<string, ISlashCommandInteractionOption> GetArguments(
                         continue;
                     }
 
-                    if (option.Value is not string stringValue)
+                    if (option.Value.Type != JsonValueType.String)
                     {
+                        var value = GetOptionValue(option);
                         arguments[parameter] = actualType.IsEnum
-                            ? Enum.ToObject(actualType, option.Value)
-                            : Convert.ChangeType(option.Value, actualType, context.Locale);
+                            ? Enum.ToObject(actualType, value)
+                            : Convert.ChangeType(value, actualType, context.Locale);
 
                         continue;
                     }
 
+                    var stringValue = option.Value.ToType<string>()!;
                     if (interaction is IAutoCompleteInteraction)
                     {
                         // Treat string values as arguments for auto-complete.
@@ -105,7 +108,7 @@ static IReadOnlyDictionary<string, ISlashCommandInteractionOption> GetArguments(
                     {
                         // If the option is just a string, pass it through to type parsing.
                         var rawArguments = context.RawArguments ??= new Dictionary<IParameter, MultiString>();
-                        rawArguments[parameter] = option.Value as string;
+                        rawArguments[parameter] = stringValue;
                         continue;
                     }
 
@@ -134,5 +137,30 @@ static IReadOnlyDictionary<string, ISlashCommandInteractionOption> GetArguments(
 
             return Next.ExecuteAsync(context);
         }
+
+        private static object GetOptionValue(ISlashCommandInteractionOption option)
+        {
+            var value = option.Value!;
+            switch (option.Type)
+            {
+                case SlashCommandOptionType.Integer:
+                {
+                    return value.ToType<long>();
+                }
+                case SlashCommandOptionType.Boolean:
+                {
+                    return value.ToType<bool>();
+                }
+                case SlashCommandOptionType.Number:
+                {
+                    return value.ToType<double>();
+                }
+                default:
+                {
+                    Throw.ArgumentOutOfRangeException(nameof(option));
+                    return default;
+                }
+            }
+        }
     }
 }

src/Disqord.Core/Disqord.Core.csproj

@@ -14,4 +14,12 @@
         <PackageReference Include="Newtonsoft.Json" Version="13.0.1"/>
         <PackageReference Include="Qommon" Version="4.0.1"/>
     </ItemGroup>
+
+    <ItemGroup Condition=" '$(TargetFramework)' == 'net6.0' ">
+        <Compile Remove="Serialization/Json/STJ/**"/>
+    </ItemGroup>
+
+    <ItemGroup Condition=" '$(TargetFramework)' != 'net6.0' ">
+        <PackageReference Include="System.Text.Json" Version="9.0.0-preview.7.24405.7"/>
+    </ItemGroup>
 </Project>

src/Disqord.Core/Entities/Core/Interactions/Commands/Slash/ISlashCommandInteractionOption.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using Disqord.Serialization.Json;
 
 namespace Disqord;
 
@@ -23,7 +24,7 @@ public interface ISlashCommandInteractionOption
     /// <remarks>
     ///     <see cref="Value"/> and <see cref="Options"/> are mutually exclusive.
     /// </remarks>
-    object? Value { get; }
+    IJsonValue? Value { get; }
 
     /// <summary>
     ///     Gets the nested options of this option.

src/Disqord.Core/Entities/Transient/ApplicationCommands/Slash/TransientSlashCommandOptionChoice.cs

@@ -25,7 +25,7 @@ public IReadOnlyDictionary<CultureInfo, string> NameLocalizations
     }
 
     /// <inheritdoc/>
-    public object Value => Model.Value.Value!;
+    public object Value => Model.Value.ToType<object>()!;
 
     public TransientSlashCommandOptionChoice(IClient client, ApplicationCommandOptionChoiceJsonModel model)
         : base(client, model)

src/Disqord.Core/Entities/Transient/Interactions/Commands/Slash/TransientSlashCommandInteractionOption.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using Disqord.Models;
+using Disqord.Serialization.Json;
 using Qommon;
 using Qommon.Collections.ReadOnly;
 
@@ -15,7 +16,7 @@ public class TransientSlashCommandInteractionOption : TransientClientEntity<Appl
     public SlashCommandOptionType Type => Model.Type;
 
     /// <inheritdoc/>
-    public object? Value => Model.Value.GetValueOrDefault()?.Value;
+    public IJsonValue? Value => Model.Value.GetValueOrDefault();
 
     /// <inheritdoc/>
     public IReadOnlyDictionary<string, ISlashCommandInteractionOption> Options

src/Disqord.Core/Library/Library.Debug.cs

@@ -10,6 +10,8 @@ public static partial class Library
     [EditorBrowsable(EditorBrowsableState.Never)]
     public static class Debug
     {
+        public static bool LogSafeDeserializationExceptions;
+
         public static bool DumpJson;
 
         public static TextWriter DumpWriter

src/Disqord.Core/Models/ApplicationCommands/ApplicationCommandOptionChoiceJsonModel.cs

@@ -23,9 +23,11 @@ protected override void OnValidate()
         Guard.HasSizeBetweenOrEqualTo(Name, Discord.Limits.ApplicationCommand.Option.Choice.MinNameLength, Discord.Limits.ApplicationCommand.Option.Choice.MaxNameLength);
 
         Guard.IsNotNull(Value);
-        Guard.IsNotNull(Value.Value);
 
-        var value = Guard.IsAssignableToType<IConvertible>(Value.Value, nameof(Value));
+        var objectValue = Value.ToType<object>();
+        Guard.IsNotNull(objectValue);
+
+        var value = Guard.IsAssignableToType<IConvertible>(objectValue, nameof(Value));
         switch (value.GetTypeCode())
         {
             case TypeCode.SByte:
@@ -62,4 +64,4 @@ protected override void OnValidate()
             }
         }
     }
-}
+}

src/Disqord.Core/Models/Extensions/JsonArrayExtensions.cs

@@ -0,0 +1,38 @@
+using System;
+using System.Collections.Generic;
+using System.Runtime.CompilerServices;
+using Disqord.Serialization.Json;
+using Microsoft.Extensions.Logging;
+
+namespace Disqord.Models;
+
+internal static class JsonArrayExtensions
+{
+    public static IEnumerable<TJsonModel> SafelyDeserializeItems<TJsonModel>(this IJsonArray jsonArray, ILogger logger, [CallerArgumentExpression(nameof(jsonArray))] string? caller = null)
+        where TJsonModel : JsonModel
+    {
+        var count = jsonArray.Count;
+        for (var i = 0; i < count; i++)
+        {
+            TJsonModel? model = null;
+            try
+            {
+                model = jsonArray[i]?.ToType<TJsonModel>();
+            }
+            catch (Exception ex)
+            {
+                if (Library.Debug.LogSafeDeserializationExceptions)
+                {
+                    logger.LogWarning(ex, "Failed to deserialize {Caller}.", caller);
+                }
+            }
+
+            if (model == null)
+            {
+                continue;
+            }
+
+            yield return model;
+        }
+    }
+}

src/Disqord.Core/Serialization/Json/Default/DefaultJsonSerializer.cs

@@ -80,7 +80,9 @@ public virtual void Serialize(Stream stream, object obj, IJsonSerializerOptions?
     public virtual IJsonNode GetJsonNode(object? obj)
     {
         if (obj == null)
+        {
             return DefaultJsonNode.Create(JValue.CreateNull(), UnderlyingSerializer);
+        }
 
         return DefaultJsonNode.Create(JToken.FromObject(obj, UnderlyingSerializer), UnderlyingSerializer);
     }
@@ -145,4 +147,4 @@ public static JsonTextWriter Conditional(IJsonSerializerOptions? options, TextWr
             return new JsonTextWriter(writer);
         }
     }
-}
+}

src/Disqord.Core/Serialization/Json/Default/Entities/ContractResolver.cs

@@ -114,7 +114,7 @@ protected override JsonObjectContract CreateObjectContract(Type objectType)
                 {
                     null => null,
                     JToken jToken => DefaultJsonNode.Create(jToken, _serializer.UnderlyingSerializer),
-                    _ => DefaultJsonNode.Create(JToken.FromObject(value, _serializer.UnderlyingSerializer), _serializer.UnderlyingSerializer)
+                    _ => DefaultJsonNode.Create(value, _serializer.UnderlyingSerializer)
                 };
 
                 model.ExtensionData.Add(key, node);

src/Disqord.Core/Serialization/Json/Default/Nodes/DefaultJsonArray.cs

@@ -18,12 +18,70 @@ public class DefaultJsonArray : DefaultJsonNode, IJsonArray
     public int Count => Token.Count;
 
     /// <inheritdoc/>
-    public IJsonNode? this[int index] => Create(Token[index], Serializer);
+    public IJsonNode? this[int index]
+    {
+        get => Create(Token[index], Serializer);
+        set => Token[index] = GetJToken(value)!;
+    }
+
+    bool ICollection<IJsonNode?>.IsReadOnly => false;
 
     public DefaultJsonArray(JArray token, JsonSerializer serializer)
         : base(token, serializer)
     { }
 
+    /// <inheritdoc/>
+    public void Add(IJsonNode? item)
+    {
+        Token.Add(GetJToken(item)!);
+    }
+
+    /// <inheritdoc/>
+    public void Clear()
+    {
+        Token.Clear();
+    }
+
+    /// <inheritdoc/>
+    public bool Contains(IJsonNode? item)
+    {
+        return Token.Contains(GetJToken(item)!);
+    }
+
+    /// <inheritdoc/>
+    public void CopyTo(IJsonNode?[] array, int arrayIndex)
+    {
+        var count = Count;
+        for (var i = 0; i < count; i++)
+        {
+            array[arrayIndex + i] = this[i];
+        }
+    }
+
+    /// <inheritdoc/>
+    public bool Remove(IJsonNode? item)
+    {
+        return Token.Remove(GetJToken(item)!);
+    }
+
+    /// <inheritdoc/>
+    public int IndexOf(IJsonNode? item)
+    {
+        return Token.IndexOf(GetJToken(item)!);
+    }
+
+    /// <inheritdoc/>
+    public void Insert(int index, IJsonNode? item)
+    {
+        Token.Insert(index, GetJToken(item)!);
+    }
+
+    /// <inheritdoc/>
+    public void RemoveAt(int index)
+    {
+        Token.RemoveAt(index);
+    }
+
     /// <inheritdoc/>
     public IEnumerator<IJsonNode?> GetEnumerator()
     {
@@ -72,4 +130,4 @@ public void Reset()
         public void Dispose()
         { }
     }
-}
+}

src/Disqord.Core/Serialization/Json/Default/Nodes/DefaultJsonNode.cs

@@ -2,6 +2,7 @@
 using System.Diagnostics.CodeAnalysis;
 using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
+using Qommon;
 
 namespace Disqord.Serialization.Json.Default;
 
@@ -16,7 +17,25 @@ public class DefaultJsonNode : IJsonNode
     /// </summary>
     public JToken Token { get; }
 
-    private protected readonly JsonSerializer Serializer;
+    /// <summary>
+    ///     Gets the underlying serializer.
+    /// </summary>
+    public JsonSerializer Serializer { get; }
+
+    /// <inheritdoc/>
+    public string Path => Token.Path;
+
+    /// <inheritdoc/>
+    public JsonValueType Type => Token.Type switch
+    {
+        JTokenType.Object => JsonValueType.Object,
+        JTokenType.Array => JsonValueType.Array,
+        JTokenType.Integer or JTokenType.Float => JsonValueType.Number,
+        JTokenType.String or JTokenType.Date or JTokenType.Raw or JTokenType.Bytes or JTokenType.Guid or JTokenType.Uri or JTokenType.TimeSpan => JsonValueType.String,
+        JTokenType.Boolean when Token.Value<bool>() => JsonValueType.True,
+        JTokenType.Boolean when !Token.Value<bool>() => JsonValueType.False,
+        _ => JsonValueType.Null
+    };
 
     public DefaultJsonNode(JToken token, JsonSerializer serializer)
     {
@@ -37,34 +56,20 @@ public DefaultJsonNode(JToken token, JsonSerializer serializer)
     /// <returns>
     ///     The string representing this node.
     /// </returns>
-    public string ToString(Formatting formatting)
+    public string ToJsonString(JsonFormatting formatting)
     {
-        return Token.ToString(formatting);
-    }
-
-    /// <summary>
-    ///     Formats this node into an indented JSON representation.
-    /// </summary>
-    /// <returns>
-    ///     The string representing this node.
-    /// </returns>
-    public override string ToString()
-    {
-        return Token.ToString(Formatting.Indented);
+        return Token.ToString(formatting switch
+        {
+            JsonFormatting.Indented => Formatting.Indented,
+            _ => Formatting.None
+        });
     }
 
-    /// <summary>
-    ///     Creates a new <see cref="DefaultJsonNode"/> from the specified object.
-    /// </summary>
-    /// <param name="obj"> The object to create the node for. </param>
-    /// <param name="serializer"> The default JSON serializer. </param>
-    /// <returns>
-    ///     A JSON node representing the object.
-    /// </returns>
-    public static IJsonNode? Create(object? obj, DefaultJsonSerializer serializer)
+    [return: NotNullIfNotNull("obj")]
+    internal static IJsonNode? Create(object? obj, JsonSerializer serializer)
     {
-        var token = obj != null ? JToken.FromObject(obj) : JValue.CreateNull();
-        return Create(token, serializer.UnderlyingSerializer);
+        var token = obj != null ? JToken.FromObject(obj, serializer) : JValue.CreateNull();
+        return Create(token, serializer);
     }
 
     [return: NotNullIfNotNull("token")]
@@ -79,4 +84,12 @@ public override string ToString()
             _ => throw new InvalidOperationException("Unknown JSON token type.")
         };
     }
-}
+
+    [return: NotNullIfNotNull("node")]
+    internal static JToken? GetJToken(IJsonNode? node)
+    {
+        return node != null
+            ? Guard.IsAssignableToType<DefaultJsonNode>(node).Token
+            : null;
+    }
+}