Bits of .NET

⚙️ Options Pattern = Configuration

Configuration is essential. Options Pattern binds configuration to objects. Strongly typed, easy to use.

📝 Options Setup

// appsettings.json
{
    "AppSettings": {
        "ApiKey": "abc-123-xyz",
        "Timeout": 30,
        "RetryCount": 3,
        "EnableLogging": true,
        "BaseUrl": "https://api.example.com"
    }
}

// Options class
public class AppSettings
{
    public string ApiKey { get; set; }
    public int Timeout { get; set; }
    public int RetryCount { get; set; }
    public bool EnableLogging { get; set; }
    public string BaseUrl { get; set; }
}

// Register options
var builder = WebApplication.CreateBuilder(args);
builder.Services.Configure(
    builder.Configuration.GetSection("AppSettings"));

// Use options (IOptions)
public class MyService
{
    private readonly AppSettings _settings;
    
    public MyService(IOptions options)
    {
        _settings = options.Value;
    }
}

🎯 Options Lifecycle

// IOptions (Singleton - cached)
public class Service1
{
    public Service1(IOptions options)
    {
        // Cached, doesn't update on config change
    }
}

// IOptionsSnapshot (Scoped - updated)
public class Service2
{
    public Service2(IOptionsSnapshot options)
    {
        // Updated when config changes
    }
}

// IOptionsMonitor (Singleton - can detect changes)
public class Service3
{
    private readonly IOptionsMonitor _monitor;
    
    public Service3(IOptionsMonitor monitor)
    {
        _monitor = monitor;
        _monitor.OnChange(settings => {
            Console.WriteLine("Config changed!");
        });
    }
}

// Validation
public class AppSettings
{
    public string ApiKey { get; set; }
    public int Timeout { get; set; }
    
    public void Validate()
    {
        if (string.IsNullOrEmpty(ApiKey))
            throw new Exception("ApiKey is required");
        
        if (Timeout < 1 || Timeout > 60)
            throw new Exception("Timeout must be between 1 and 60");
    }
}

// Options Tips
- Use IOptions for static config
- Use IOptionsSnapshot for dynamic config
- Use IOptionsMonitor for change detection
- Validate configuration
- Use nested options for complex config

💡 Options Tips

• Use IOptions for static config
• Use IOptionsSnapshot for dynamic config
• Use IOptionsMonitor for change detection
• Validate configuration
• Use nested options for complex config