.NET\06_Microservices_Users\Users.API\Controllers\TokensController.cs

                
                    using MediatR;
using Microsoft.AspNetCore.Mvc;
using Users.APP.Features.Authentication;

namespace Users.API.Controllers
{
    /// <summary>
    /// API controller for handling token-related operations 
    /// such as generating new JWT and refreshing JWT.
    /// </summary>
    [Route("api/[controller]")] // Sets the base route for
                                // this controller to "api/tokens"
                                // (controller name is replaced at
                                // runtime).
    [ApiController] // Indicates that this class is an API controller
                    // and enables automatic model validation and
                    // binding.
    public class TokensController : ControllerBase
    {
        private readonly IMediator _mediator; 
        // instance of type implementing IMediator will be injected
        // to this variable in the constructor
        private readonly IConfiguration _configuration;
        // instance of type implementing IConfiguration will be
        // injected to this variable in the constructor

        /// <summary>
        /// Injects the mediator instance and application's configuration 
        /// instance for getting configuration values from such as
        /// appsettings.json.
        /// </summary>
        /// <param name="mediator">The mediator instance for 
        /// sending requests.</param>
        /// <param name="configuration">The application's configuration 
        /// settings instance for getting configuration values.</param>
        public TokensController(IMediator mediator, 
            IConfiguration configuration)
        {
            _mediator = mediator;
            _configuration = configuration;
        }

        /// <summary>
        /// Handles HTTP POST requests to generate a new JWT and 
        /// refresh token for a user.
        /// </summary>
        /// <param name="request">The token request containing 
        /// user credentials (user name and password).</param>
        /// <returns>
        /// An IActionResult containing the JWT response if 
        /// authentication operation is successful, or an error message 
        /// if authentication operation fails or the request is invalid.
        /// </returns>
        [HttpPost] // Specifies that this action responds to
                   // HTTP POST requests.
        [Route("~/api/[action]")] // Overrides the controller's base route.
                                  // The route becomes "api/Token"
                                  // (action name is replaced at runtime).
        public async Task<IActionResult> Token(TokenRequest request)
        {
            request.SecurityKey = _configuration["SecurityKey"]; 
            // get the SecurityKey section value from the previously added
            // section in Program.cs
            request.Audience = _configuration["Audience"]; 
            // get the Audience section value from appsettings.json
            request.Issuer = _configuration["Issuer"]; 
            // get the Issuer section value from appsettings.json
            if (ModelState.IsValid)
            {
                var response = await _mediator.Send(request);
                if (response is not null)
                    return Ok(response);
                return NotFound(_configuration["TokenMessage:NotFound"]); 
                // return the NotFound section value of the TokenMessage section
                // from appsettings.json as a HTTP 404 NotFound response
            }
            return BadRequest(_configuration["TokenMessage:BadRequest"]); 
            // return the BadRequest section value of the TokenMessage section
            // from appsettings.json as a HTTP 400 BadRequest response
        }

        /// <summary>
        /// Handles HTTP POST requests to refresh the JWT and the refresh token 
        /// for a user.
        /// </summary>
        /// <param name="request">The refresh token request containing the 
        /// previously generated expired JWT and refresh token.</param>
        /// <returns>
        /// An IActionResult containing the new JWT response if the refresh 
        /// operation is successful, or an error message if the refresh operation 
        /// fails or the request is invalid.
        /// </returns>
        [HttpPost] // Specifies that this action responds to
                   // HTTP POST requests.
        [Route("~/api/[action]")] // Overrides the controller's base route.
                                  // The route becomes "api/RefreshToken"
                                  // (action name is replaced at runtime).
        public async Task<IActionResult> RefreshToken(RefreshTokenRequest request)
        {
            request.SecurityKey = _configuration["SecurityKey"]; 
            // get the SecurityKey section value from the previously added
            // section in Program.cs
            request.Audience = _configuration["Audience"]; 
            // get the Audience section value from appsettings.json
            request.Issuer = _configuration["Issuer"]; 
            // get the Issuer section value from appsettings.json
            if (ModelState.IsValid)
            {
                var response = await _mediator.Send(request);
                if (response is not null)
                    return Ok(response);
                return NotFound(_configuration["TokenMessage:NotFound"]); 
                // return the NotFound section value of the TokenMessage section
                // from appsettings.json as a HTTP 404 NotFound response
            }
            return BadRequest(_configuration["TokenMessage:BadRequest"]); 
            // return the BadRequest section value of the TokenMessage section
            // from appsettings.json as a HTTP 400 BadRequest response
        }
    }
}