Add SystemTextJsonSerializer base class and relevant extensions methods

src/Elastic.Transport/Components/Serialization/IJsonSerializerOptionsProvider.cs

@@ -0,0 +1,61 @@
+// Licensed to Elasticsearch B.V under one or more agreements.
+// Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
+// See the LICENSE file in the project root for more information
+
+using System;
+using System.Collections.Generic;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace Elastic.Transport;
+
+/// <summary>
+/// Provides an instance of <see cref="JsonSerializerOptions"/> to <see cref="SystemTextJsonSerializer"/>
+/// </summary>
+public interface IJsonSerializerOptionsProvider
+{
+	/// <inheritdoc cref="IJsonSerializerOptionsProvider"/>
+	JsonSerializerOptions CreateJsonSerializerOptions();
+}
+
+/// <summary>
+/// Default implementation of <see cref="IJsonSerializerOptionsProvider"/> specialized in providing more converters and
+/// altering the shared <see cref="JsonSerializerOptions"/> used by <see cref="SystemTextJsonSerializer"/> and its derived classes
+/// </summary>
+public class TransportSerializerOptionsProvider : IJsonSerializerOptionsProvider
+{
+	private readonly IReadOnlyCollection<JsonConverter>? _bakedInConverters;
+	private readonly IReadOnlyCollection<JsonConverter>? _userProvidedConverters;
+	private readonly Action<JsonSerializerOptions>? _mutateOptions;
+
+	/// <inheritdoc cref="IJsonSerializerOptionsProvider"/>
+	public JsonSerializerOptions? CreateJsonSerializerOptions()
+	{
+		var options = new JsonSerializerOptions();
+
+		foreach (var converter in _bakedInConverters ?? [])
+			options.Converters.Add(converter);
+
+		foreach (var converter in _userProvidedConverters ?? [])
+			options.Converters.Add(converter);
+
+		_mutateOptions?.Invoke(options);
+
+		return options;
+	}
+
+	/// <inheritdoc cref="TransportSerializerOptionsProvider"/>
+	public TransportSerializerOptionsProvider() { }
+
+	/// <inheritdoc cref="TransportSerializerOptionsProvider"/>
+	public TransportSerializerOptionsProvider(
+		IReadOnlyCollection<JsonConverter> bakedInConverters,
+		IReadOnlyCollection<JsonConverter>? userProvidedConverters,
+		Action<JsonSerializerOptions>? mutateOptions = null
+	)
+	{
+		_bakedInConverters = bakedInConverters;
+		_userProvidedConverters = userProvidedConverters;
+		_mutateOptions = mutateOptions;
+	}
+}

src/Elastic.Transport/Components/Serialization/LowLevelRequestResponseSerializer.cs

@@ -2,138 +2,36 @@
 // Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
 // See the LICENSE file in the project root for more information
 
-using System;
 using System.Collections.Generic;
-using System.Collections.ObjectModel;
-using System.IO;
-using System.Linq;
 using System.Text.Json;
 using System.Text.Json.Serialization;
-using System.Threading;
-using System.Threading.Tasks;
-using Elastic.Transport.Extensions;
-using static Elastic.Transport.SerializationFormatting;
 
 namespace Elastic.Transport;
 
 /// <summary>
-/// Default implementation for <see cref="Serializer"/>. This uses <see cref="JsonSerializer"/> from <code>System.Text.Json</code>.
+/// Default low level request/response-serializer implementation for <see cref="Serializer"/> which serializes using
+/// the Microsoft <c>System.Text.Json</c> library
 /// </summary>
-internal sealed class LowLevelRequestResponseSerializer : Serializer
+internal sealed class LowLevelRequestResponseSerializer : SystemTextJsonSerializer
 {
 	/// <summary>
 	/// Provides a static reusable reference to an instance of <see cref="LowLevelRequestResponseSerializer"/> to promote reuse.
 	/// </summary>
 	internal static readonly LowLevelRequestResponseSerializer Instance = new();
 
-	private readonly Lazy<JsonSerializerOptions> _indented;
-	private readonly Lazy<JsonSerializerOptions> _none;
-
-	private IReadOnlyCollection<JsonConverter> AdditionalConverters { get; }
-
-	private IList<JsonConverter> BakedInConverters { get; } = new List<JsonConverter>
-		{
-			new ExceptionConverter(),
-			new ErrorCauseConverter(),
-			new ErrorConverter(),
-			new DynamicDictionaryConverter()
-		};
-
 	/// <inheritdoc cref="LowLevelRequestResponseSerializer"/>>
 	public LowLevelRequestResponseSerializer() : this(null) { }
 
 	/// <summary>
 	/// <inheritdoc cref="LowLevelRequestResponseSerializer"/>>
 	/// </summary>
 	/// <param name="converters">Add more default converters onto <see cref="JsonSerializerOptions"/> being used</param>
-	public LowLevelRequestResponseSerializer(IEnumerable<JsonConverter>? converters)
-	{
-		AdditionalConverters = converters != null
-			? new ReadOnlyCollection<JsonConverter>(converters.ToList())
-			: EmptyReadOnly<JsonConverter>.Collection;
-		_indented = new Lazy<JsonSerializerOptions>(() => CreateSerializerOptions(Indented));
-		_none = new Lazy<JsonSerializerOptions>(() => CreateSerializerOptions(None));
-	}
-
-	/// <summary>
-	/// Creates <see cref="JsonSerializerOptions"/> used for serialization.
-	/// Override on a derived serializer to change serialization.
-	/// </summary>
-	public JsonSerializerOptions CreateSerializerOptions(SerializationFormatting formatting)
-	{
-		var options = new JsonSerializerOptions
-		{
-			DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
-			WriteIndented = formatting == Indented,
-		};
-		foreach (var converter in BakedInConverters)
-			options.Converters.Add(converter);
-		foreach (var converter in AdditionalConverters)
-			options.Converters.Add(converter);
-
-		return options;
-
-	}
-
-	private static bool TryReturnDefault<T>(Stream? stream, out T deserialize)
-	{
-		deserialize = default;
-		return stream == null || stream == Stream.Null || (stream.CanSeek && stream.Length == 0);
-	}
-
-	private JsonSerializerOptions GetFormatting(SerializationFormatting formatting) => formatting == None ? _none.Value : _indented.Value;
-
-	/// <inheritdoc cref="Serializer.Deserialize"/>>
-	public override object Deserialize(Type type, Stream stream)
-	{
-		if (TryReturnDefault(stream, out object deserialize)) return deserialize;
-
-		return JsonSerializer.Deserialize(stream, type, _none.Value)!;
-	}
-
-	/// <inheritdoc cref="Serializer.Deserialize{T}"/>>
-	public override T Deserialize<T>(Stream stream)
-	{
-		if (TryReturnDefault(stream, out T deserialize)) return deserialize;
-
-		return JsonSerializer.Deserialize<T>(stream, _none.Value);
-	}
-
-	/// <inheritdoc cref="Serializer.Serialize{T}"/>>
-	public override void Serialize<T>(T data, Stream stream, SerializationFormatting formatting = None)
-	{
-		using var writer = new Utf8JsonWriter(stream);
-		if (data == null)
-			JsonSerializer.Serialize(writer, null, typeof(object), GetFormatting(formatting));
-		//TODO validate if we can avoid boxing by checking if data is typeof(object)
-		else
-			JsonSerializer.Serialize(writer, data, data.GetType(), GetFormatting(formatting));
-	}
-
-	/// <inheritdoc cref="Serializer.SerializeAsync{T}"/>>
-	public override async Task SerializeAsync<T>(T data, Stream stream, SerializationFormatting formatting = None,
-		CancellationToken cancellationToken = default
-	)
-	{
-		if (data == null)
-			await JsonSerializer.SerializeAsync(stream, null, typeof(object), GetFormatting(formatting), cancellationToken).ConfigureAwait(false);
-		else
-			await JsonSerializer.SerializeAsync(stream, data, data.GetType(), GetFormatting(formatting), cancellationToken).ConfigureAwait(false);
-	}
-
-	/// <inheritdoc cref="Serializer.DeserializeAsync"/>>
-	public override ValueTask<object> DeserializeAsync(Type type, Stream stream, CancellationToken cancellationToken = default)
-	{
-		if (TryReturnDefault(stream, out object deserialize)) return new ValueTask<object>(deserialize);
-
-		return JsonSerializer.DeserializeAsync(stream, type, _none.Value, cancellationToken);
-	}
-
-	/// <inheritdoc cref="Serializer.DeserializeAsync{T}"/>>
-	public override ValueTask<T> DeserializeAsync<T>(Stream stream, CancellationToken cancellationToken = default)
-	{
-		if (TryReturnDefault(stream, out T deserialize)) return new ValueTask<T>(deserialize);
+	public LowLevelRequestResponseSerializer(IReadOnlyCollection<JsonConverter>? converters)
+		: base(new TransportSerializerOptionsProvider([
+			new ExceptionConverter(),
+			new ErrorCauseConverter(),
+			new ErrorConverter(),
+			new DynamicDictionaryConverter()
+		], converters, options => { options.DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull; })) { }
 
-		return JsonSerializer.DeserializeAsync<T>(stream, _none.Value, cancellationToken);
-	}
 }

src/Elastic.Transport/Components/Serialization/Serializer.cs

@@ -32,6 +32,8 @@ public abstract class Serializer
 	/// <inheritdoc cref="Deserialize"/>
 	public abstract ValueTask<T> DeserializeAsync<T>(Stream stream, CancellationToken cancellationToken = default);
 
+	// TODO: Overloads for (object?, Type) inputs
+
 	/// <summary>
 	/// Serialize an instance of <typeparamref name="T"/> to <paramref name="stream"/> using <paramref name="formatting"/>.
 	/// </summary>

src/Elastic.Transport/Components/Serialization/SystemTextJsonSerializer.cs

@@ -0,0 +1,102 @@
+// Licensed to Elasticsearch B.V under one or more agreements.
+// Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
+// See the LICENSE file in the project root for more information
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Elastic.Transport;
+
+/// <summary>
+/// An abstract implementation of a transport <see cref="Serializer"/> which serializes using the Microsoft
+/// <c>System.Text.Json</c> library.
+/// </summary>
+public abstract class SystemTextJsonSerializer : Serializer
+{
+	private readonly JsonSerializerOptions? _options;
+	private readonly JsonSerializerOptions? _indentedOptions;
+
+	/// <summary>
+	/// An abstract implementation of a transport <see cref="Serializer"/> which serializes using the Microsoft
+	/// <c>System.Text.Json</c> library.
+	/// </summary>
+	protected SystemTextJsonSerializer(IJsonSerializerOptionsProvider? provider = null)
+	{
+		provider ??= new TransportSerializerOptionsProvider();
+		_options = provider.CreateJsonSerializerOptions();
+		_indentedOptions = new JsonSerializerOptions(_options)
+		{
+			WriteIndented = true
+		};
+	}
+
+	#region Serializer
+
+	/// <inheritdoc />
+	public override T Deserialize<T>(Stream stream)
+	{
+		if (TryReturnDefault(stream, out T deserialize))
+			return deserialize;
+
+		return JsonSerializer.Deserialize<T>(stream, GetJsonSerializerOptions());
+	}
+
+	/// <inheritdoc />
+	public override object? Deserialize(Type type, Stream stream)
+	{
+		if (TryReturnDefault(stream, out object deserialize))
+			return deserialize;
+
+		return JsonSerializer.Deserialize(stream, type, GetJsonSerializerOptions());
+	}
+
+	/// <inheritdoc />
+	public override ValueTask<T> DeserializeAsync<T>(Stream stream, CancellationToken cancellationToken = default)
+	{
+		if (TryReturnDefault(stream, out T deserialize))
+			return new ValueTask<T>(deserialize);
+
+		return JsonSerializer.DeserializeAsync<T>(stream, GetJsonSerializerOptions(), cancellationToken);
+	}
+
+	/// <inheritdoc />
+	public override ValueTask<object?> DeserializeAsync(Type type, Stream stream, CancellationToken cancellationToken = default)
+	{
+		if (TryReturnDefault(stream, out object deserialize))
+			return new ValueTask<object?>(deserialize);
+
+		return JsonSerializer.DeserializeAsync(stream, type, GetJsonSerializerOptions(), cancellationToken);
+	}
+
+	/// <inheritdoc />
+	public override void Serialize<T>(T data, Stream writableStream,
+		SerializationFormatting formatting = SerializationFormatting.None) =>
+		JsonSerializer.Serialize(writableStream, data, GetJsonSerializerOptions(formatting));
+
+	/// <inheritdoc />
+	public override Task SerializeAsync<T>(T data, Stream stream,
+		SerializationFormatting formatting = SerializationFormatting.None,
+		CancellationToken cancellationToken = default) =>
+		JsonSerializer.SerializeAsync(stream, data, GetJsonSerializerOptions(formatting), cancellationToken);
+
+	#endregion Serializer
+
+	/// <summary>
+	/// Returns the <see cref="JsonSerializerOptions"/> for this serializer, based on the given <paramref name="formatting"/>.
+	/// </summary>
+	/// <param name="formatting">The serialization formatting.</param>
+	/// <returns>The requested <see cref="JsonSerializerOptions"/> or <c>null</c>, if the serializer is not initialized yet.</returns>
+	protected internal JsonSerializerOptions? GetJsonSerializerOptions(SerializationFormatting formatting = SerializationFormatting.None) =>
+		formatting is SerializationFormatting.None ? _options : _indentedOptions;
+
+	private static bool TryReturnDefault<T>(Stream? stream, out T deserialize)
+	{
+		deserialize = default;
+		return (stream is null) || stream == Stream.Null || (stream.CanSeek && stream.Length == 0);
+	}
+}