Unit testing and multiple parameters to constructors in Asp.Net Core MVC, Passing token to every request

Question

I am trying to add one more parameter to my constructors in my Asp.Net Core MVC application, but facing some difficulties to do so. Here is what my implementation looks like.

Login action:

[HttpPost, AllowAnonymous, ValidateAntiForgeryToken]
public IActionResult Login(LoginViewModel loginModel, string returnUrl = null)
{
   returnUrl = string.IsNullOrWhiteSpace(returnUrl) ? ApiConstants.Dashboard : returnUrl;
   ViewData["ReturnUrl"] = returnUrl;
   if (!ModelState.IsValid) return View(loginModel);
   var token = Service.Login(loginModel);
   if (string.IsNullOrWhiteSpace(token)) return View(loginModel);
   TempData["token"] = token;
   AddCookie(token);
   return RedirectToAction("Index", "Dashboard");
}

private void AddCookie(string token)
{
   HttpContext.Response.Cookies.Append("token", token,new CookieOptions()
   {
      Expires = DateTimeOffset.Now.AddDays(-1)
   });
}

Controller:

private readonly INozzleService _nozzleService;
public NozzleController(INozzleService nozzleService)
{
  var token = HttpContext.Request.Cookies["token"];
  _nozzleService = nozzleService;
}

Nozzle Service:

private static INozzleAdapter Adapter { get; set; }
public NozzleService(INozzleAdapter adapter)
{
  Adapter = adapter;
}

Nozzle Adapter:

private readonly string _token;
public NozzleAdapter(string token)
{
   _token = token;
}

Once I get the token in the adapter, I will be adding the token to the HttpClient header.

client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", _token);

ConfigureServices in Startup:

public void ConfigureServices(IServiceCollection services)
{
   services.AddSingleton<ITempDataProvider, CookieTempDataProvider>();
   services.AddDistributedMemoryCache();
   services.AddSession();
   services.AddTransient<IAccountService, AccountService>();
   services.AddTransient<IAccountAdapter, AccountAdapter>();
   services.AddTransient<INozzleService, NozzleService>();
   services.AddTransient<INozzleAdapter, NozzleAdapter>();
   services.AddMvc();
}

Can you please let me know what could be the best way to achieve this in Asp.Net core 2.0 MVC application? I have read a post saying that using multiple constructors is not a good idea in Asp.Net Core MVC application, so I don't want to use multiple constructors.

At the same time, I want to make sure all of my classes are unit testable with DI. What should be the best approach here?

Please let me know if anyone needs more information.

Update:

As per Shyju's solution, I was able to implement the cookie, however, I am still in a need to pass two parameters to one of my controllers.

private readonly IAccountService _service;
private readonly ITokenProvider _tokenProvider;
public AccountController(IAccountService service, ITokenProvider tokenProvider)
{
  _service = service;
  _tokenProvider = tokenProvider;
}

So that I can, use the method AddToken as below.

_tokenProvider.AddToken(token);

Answer 1

You may consider abstracting out the logic to get the token to a separate class and inject that as needed.

public interface ITokenProvider
{
    /// <summary>
    /// Gets the token
    /// </summary>
    /// <returns></returns>
    string GetToken();
}

Now create an implementation of this, which will be reading the token from the cookie. Here is a simple implementation, which reads the token from the cookies collection

public class CookieTokenProvider : ITokenProvider
{
    private readonly IHttpContextAccessor httpContextAccessor;

    public CookieTokenProvider(IHttpContextAccessor httpContextAccessor)
    {
        this.httpContextAccessor = httpContextAccessor;
    }
    public string GetToken()
    {
        if (httpContextAccessor.HttpContext.Request.Cookies
                                           .TryGetValue("token", out string tokenValue))
        {
            return tokenValue;
        }
        return null;
    }
}

Now, you can inject the ITokenProvider implementation to anyplace you want and call the GetToken method to get the token value. For example, you may inject this to the NozzleAdapter class constructor.

private readonly ITokenProvider tokenProvider;
public NozzleAdapter(ITokenProvider tokenProvider)
{
   tokenProvider=tokenProvider;
}
public string SomeOtherMethod()
{
   var token = this.tokenProvider.GetToken();
   //Do null check and use it
}

Make sure you register this in the ConfigureServices method in Startup class

services.AddTransient<ITokenProvider, CookieTokenProvider>();

Regarding your comment about getting the token and persisting it, it is up to you where you want to do it. You can do that in the CookieTokenProvider implementation. Read the value and store it somewhere ( a local db, in memory cache etc) and get it from there if exists (the next time)

Now, for your unit tests you can create a MockTokenProvider which does not use HttpContext, but simply return a mock value for your testing,

public class MockTokenProvider : ITokenProvider
{
    public string GetToken() => "FakeToken";
}