Using options pattern in a different way

[amirhessampourhossein]

Currently, this is how your JwtSettings is configured 👇

var jwtSettings = new JwtSettings();
configuration.Bind(JwtSettings.Section, jwtSettings);
services.AddSingleton(Options.Create(jwtSettings));

What's your opinion about the approach below 👇

services.AddOptions<JwtSettings>().BindConfiguration(JwtSettings.Section);

we could also add validation in two different ways :

• Data Annotations (built-in)

  services.AddOptions<JwtSettings>()
  .BindConfiguration(JwtSettings.Section)
  .ValidateDataAnnotations()
  .ValidateOnStart();

• Fluent Validation

  public class FluentValidateOptions<TOptions>
  : IValidateOptions<TOptions>
  where TOptions : class
  {
  private readonly IServiceProvider _serviceProvider;
  private readonly string? _name;
  
  public FluentValidateOptions(IServiceProvider serviceProvider, string? name)
  {
      _serviceProvider = serviceProvider;
      _name = name;
  }
  
  public ValidateOptionsResult Validate(string? name, TOptions options)
  {
      if (_name is not null && _name != name)
          return ValidateOptionsResult.Skip;
  
      ArgumentNullException.ThrowIfNull(options);
  
      using var scope = _serviceProvider.CreateScope();
  
      var validator = scope.ServiceProvider.GetRequiredService<IValidator<TOptions>>();
  
      var result = validator.Validate(options);
  
      if (result.IsValid)
          return ValidateOptionsResult.Success;
  
      var errors = result.Errors
          .Select(x => $"Validation failed for {x.PropertyName} with the error: {x.ErrorMessage}")
          .ToList();
  
      return ValidateOptionsResult.Fail(errors);
  }

  public static OptionsBuilder<TOptions> ValidateFluentValidation<TOptions>(
      this OptionsBuilder<TOptions> optionsBuilder)
      where TOptions : class
  {
      optionsBuilder.Services.AddSingleton<IValidateOptions<TOptions>>(
          serviceProvider => new FluentValidateOptions<TOptions>(
              serviceProvider,
              optionsBuilder.Name
              ));
      return optionsBuilder;
  }

  builder.Services.AddOptions<JwtSettings>()
  .BindConfiguration(JwtSettings.ConfigurationSectionName)
  .ValidateFluentValidation()
  .ValidateOnStart();

[amantinband]

Generally I go with what you suggested, but over here we need to both register the settings as singleton and use it a few lines later:

Regarding validation, not sure I want to add this to the template, but let me think about it. Keeping the issue open for now

[amirhessampourhossein]

What about separating the second part and putting it in another class that implements IConfigureOptions<JwtBearerOptions> ?

[amantinband]

Yeah that's a good option as well. Feel free to create a PR for this if you'd like :)

[amantinband]

Thanks Amir! 🫶