Call two Action Methods and Combine the responses to produce new response in .NET Web API

I have two versions of an API.

The second version of API will be having only one action method instead of two action methods in first version of API.

Second version of API action method will basically combine responses of first version of API's both action methods and return combined response to client.

Example code as follows:

[ApiController]
[Route("[controller]")]
public class NumbersV1Controller : ControllerBase
{
    private readonly ILogger<NumbersV1Controller> _logger;

    public NumbersV1Controller(ILogger<NumbersV1Controller> logger)
    {
        _logger = logger;
    }

    [HttpGet]
    public int Get()
    {
        return 1;
    }

    [HttpPost]
    public int Post()
    {
        return 2;
    }
}

[ApiController]
[Route("[controller]")]
public class NumbersV2Controller : ControllerBase
{
    private readonly ILogger<NumbersV2Controller> _logger;

    public NumbersV2Controller(ILogger<NumbersV2Controller> logger)
    {
        _logger = logger;
    }

    [HttpPost]
    public IEnumerable<int> Get()
    {
        // Method 1: Make a direct HTTP request.
        // int response1 = HTTPClientHelper.GetRequest("Get", "NumbersV1");
        // int response2 = HTTPClientHelper.PostRequest("Post", "NumbersV1");

        // Method 2: Use instances and set controller context.
        NumbersV1Controller numbersV1Controller = new NumbersV1Controller(null);
        numbersV1Controller.ControllerContext = this.ControllerContext;
        int response1 = numbersV1Controller.Get();
        int response2 = numbersV1Controller.Post();

        // Method 3: Use RedirectToAction method.
        // RedirectToActionResult response1 = RedirectToAction("Get", "NumbersV1");
        // RedirectToActionResult response2 = RedirectToAction("Post", "NumbersV1");

        return new List<int>() { response1, response2 };
    }
}

1. Method 1: Make a direct HTTP request.

   It works perfectly but it is having additional boilerplate code and also it like making a new network call.

2. Method 2: Use instances and set controller context.

   Not sure if this will work perfectly like can I access the Request object in version 1 controller and not sure how to initialize the version 2 controller will multiple injected objects

3. Method 3: Use RedirectToAction method.

   I was assuming RedirectToAction will work but I don't see the result of the Action method in response object RedirectToActionResult.

What are the best options available for doing this in .NET Web API or is there any other way of doing this elegently?

Avoid using method 2 / method 3. Why? It violates so many patterns and performance will be an issue.

Method 1 is average if you really want to do it that way but will cost a network call though.

Method 4:
You can call directly inline business logic code from your V2 controller. If you already separated your business logic code to an individual service then you need to call it from your controller.

> I have introduced a new class to do all the logical operations. You might have a similar one / many service classes for handling business requirements.

Let me give you an example:

public class Number1Controller : BaseController {
    // You can use DI container to resolve this. I am using this as an example.
    private readonly Service _service = new();

    [HttpGet("{id}")]
    public int GetById(int id) => _service.GetById(id);

    [HttpGet("{name}")]
    public string GetByName(string name) => _service.GetByName(name);
}

public class Number2Controller : BaseController {

    // You can use DI container to resolve this. I am using this as an example.
    private readonly Service _service = new();
    
    [HttpGet("{id}")]
    public int GetById(int id) => _service.GetById(id);

    [HttpGet("{name}")]
    public string GetByName(string name) => _service.GetByName(name);
}

// Business Logic Service
public class Service {
    public int GetById(int id) => 1;
    public string GetByName(string name) => "Stack Over Flow";
}