Handling JSON without allocations C# ASP.NET Core

Handling JSON without allocations C# ASP.NET Core

	private static readonly byte[] Utf8TextJobCategory =
	Encoding.UTF8.GetBytes("JobCategory");
	private static readonly byte[] Utf8TextDepartmentId =
	Encoding.UTF8.GetBytes("DepartmentId");
	private static readonly byte[] Utf8TextArduous = Encoding.UTF8.GetBytes("arduous");
	private static readonly byte[] Utf8TextTedious = Encoding.UTF8.GetBytes("tedious");
	[HttpPost]
	[Route("/jobs/create")]
	public async ValueTask CreateJobFrugalAsync()
	{
	bool inDepartmentIdProperty = false;
	bool inJobCategoryProperty = false;
	int? departmentId = null;
	bool? isArduous = null;
	PipeReader reader = this.Request.BodyReader;
	JsonReaderState jsonState = default;
	while (true)
	{
	ReadResult result = await reader.ReadAsync().ConfigureAwait(false);
	jsonState = ProcessBuffer(
	result,
	jsonState,
	out SequencePosition position);
	if (departmentId.HasValue && isArduous.HasValue)
	{
	if (isArduous.Value)
	{
	CreateArduousJob(departmentId.Value);
	}
	else
	{
	CreateTediousJob(departmentId.Value);
	}
	return;
	}
	reader.AdvanceTo(position);
	if (result.IsCompleted)
	{
	break;
	}
	}
	JsonReaderState ProcessBuffer(
	in ReadResult result,
	in JsonReaderState jsonState,
	out SequencePosition position)
	{
	// This is a ref struct, so this has no GC overhead
	var r = new Utf8JsonReader(result.Buffer, result.IsCompleted, jsonState);
	while (r.Read())
	{
	if (inDepartmentIdProperty)
	{
	if (r.TokenType == JsonTokenType.Number)
	{
	if (r.TryGetInt32(out int v))
	{
	departmentId = v;
	}
	}
	}
	else if (inJobCategoryProperty)
	{
	if (r.TokenType == JsonTokenType.String)
	{
	if (r.ValueSpan.SequenceEqual(Utf8TextArduous))
	{
	isArduous = true;
	}
	else if (r.ValueSpan.SequenceEqual(Utf8TextTedious))
	{
	isArduous = false;
	}
	}
	}
	inDepartmentIdProperty = false;
	inJobCategoryProperty = false;
	if (r.TokenType == JsonTokenType.PropertyName)
	{
	if (r.ValueSpan.SequenceEqual(Utf8TextJobCategory))
	{
	inJobCategoryProperty = true;
	}
	else if (r.ValueSpan.SequenceEqual(Utf8TextDepartmentId))
	{
	inDepartmentIdProperty = true;
	}
	}
	}
	position = r.Position;
	return r.CurrentState;
	}
	}

view raw allocator.cs hosted with ❤ by GitHub

	[HttpPost]
	[Route("/jobs/create")]
	public void CreateJob([FromBody] JobDescription requestBody)
	{
	switch (requestBody.JobCategory)
	{
	case "arduous":
	CreateArduousJob(requestBody.DepartmentId);
	break;
	case "tedious":
	CreateTediousJob(requestBody.DepartmentId);
	break;
	}
	}
	public class JobDescription
	{
	public int DepartmentId { get; set; }
	public string JobCategory { get; set; }
	}

view raw notallocator.cs hosted with ❤ by GitHub