ProjectsController.cs

using Microsoft.AspNetCore.Mvc;
using System.Collections.Concurrent;

namespace HTTPFileTryOut.Controllers
{
    [ApiController]
    [Route("api/[controller]")]
    public class ProjectsController : ControllerBase
    {
        private static readonly ConcurrentDictionary<Guid, Project> Projects = new();

        [HttpPost]
        public IActionResult CreateProject([FromBody] CreateProjectRequest request)
        {
            var project = new Project
            {
                Id = Guid.NewGuid(),
                Name = request.Name,
                Tasks = new List<ProjectTask>()
            };
            Projects[project.Id] = project;
            return CreatedAtAction(nameof(GetProject), new { id = project.Id }, project);
        }

        [HttpGet("{id}")]
        public IActionResult GetProject(Guid id)
        {
            if (Projects.TryGetValue(id, out var project))
                return Ok(project);
            return NotFound();
        }

        [HttpPost("{projectId}/tasks")]
        public IActionResult AddTask(Guid projectId, [FromBody] AddTaskRequest request)
        {
            if (!Projects.TryGetValue(projectId, out var project))
                return NotFound();
            var task = new ProjectTask
            {
                Id = Guid.NewGuid(),
                Title = request.Title,
                Description = request.Description
            };
            project.Tasks.Add(task);
            return Created($"api/projects/{projectId}/tasks/{task.Id}", task);
        }
    }

    public class Project
    {
        public Guid Id { get; set; }
        public string Name { get; set; }
        public List<ProjectTask> Tasks { get; set; }
    }

    public class ProjectTask
    {
        public Guid Id { get; set; }
        public string Title { get; set; }
        public string Description { get; set; }
    }

    public class CreateProjectRequest
    {
        public string Name { get; set; }
    }

    public class AddTaskRequest
    {
        public string Title { get; set; }
        public string Description { get; set; }
    }
}