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! 🫶