Options Pattern

IOptions Pattern in ASP.NET Core in 4 Steps

This is a pattern that allows you to inject strongly typed configuration settings into your classes. It is a great way to keep your configuration settings in one place and to avoid having to use the IConfiguration interface directly in your classes.

How to use it

mkdir IOptionsPatternDemo
cd IOptionsPatternDemo

Create a new ASP.NET Core Web Application

dotnet new webapi -o IOptionsPatternDemo
cd IOptionsPatternDemo

Step 1. Create a new class called JwtSettings in the Models folder

 public class JwtSettings
    {
        public string Secret { get; set; } = string.Empty;

        public string Issuer { get; set; } = string.Empty;

        public string Audience { get; set; } = string.Empty;

        public int ExpirationInMinutes { get; set; } = 0;
    }

Step 2. Add the following to the appsettings.json file

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*",
  "JwtSettings": {
    "Secret": "Damaam",
    "Issuer": "me",
    "Audience": "me",
    "ExpirationInMinutes": 90
  }
}

Step 3. Add the following to the Program.cs file

using OptionsPattern.Models;

var builder = WebApplication.CreateBuilder(args);


builder.Services.Configure<JwtSettings>(builder.Configuration.GetSection("JwtSettings")); // <--- Add this line
builder.Services.AddControllers();
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

var app = builder.Build();

if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseHttpsRedirection();

app.UseAuthorization();
app.MapControllers();

app.Run();

Create a new controller called UserController in the Controllers folder

  [ApiController]
    [Route("api/[controller]")]
    public class UserControllers : ControllerBase
    {
        private readonly IOptions<JwtSettings> _jwtSettings;

        public UserControllers(IOptions<JwtSettings> jwtSettings)
        {
            _jwtSettings = jwtSettings;
        }

        [HttpGet]
        public IActionResult Get()
        {
            return Ok(_jwtSettings.Value);
        }

        //GET A SPECIFIC VALUE
        [HttpGet("{key}")]
        public IActionResult Get(string key)
        {
            var value = _jwtSettings.Value.GetType().GetProperty(key)?.GetValue(_jwtSettings.Value, null);
            return Ok(value);
        }



    }

Run the application

dotnet run