MahmudX / nswag-fluentvalidation

Use FluentValidation rules instead of ComponentModel attributes to define swagger schema.

ZymLabs.NSwag.FluentValidation

Use FluentValidation rules to define validation requirements for NSwag Swagger/OpenAPI schema.

This project has been split into two packages.

• ZymLabs.NSwag.FluentValidation
  • Provides the core logic, can be included in an application project.
• ZymLabs.NSwag.FluentValidation.AspNetCore
  • Provides the AspNetCore HTTP helpers such as the HttpContextServiceProviderValidatorFactory for supporting HttpContext scoped services when using FluentValidation with DB Context validators.

Statuses

Usage

1. Reference packages in your web project:

dotnet add package ZymLabs.NSwag.FluentValidation.AspNetCore

Or if you want to use the core package for your application without the AspNetCore MVC dependencies.

dotnet add package ZymLabs.NSwag.FluentValidation

2. Change Startup.cs

// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
    // HttpContextServiceProviderValidatorFactory requires access to HttpContext
    services.AddHttpContextAccessor();

    services
        .AddControllers()

        // Adds fluent validators to Asp.net
        .AddFluentValidation(c =>
        {
            c.RegisterValidatorsFromAssemblyContaining<Startup>();

            // Optionally set validator factory if you have problems with scope resolve inside validators.
            c.ValidatorFactoryType = typeof(HttpContextServiceProviderValidatorFactory);
        })

    services.AddOpenApiDocument((settings, serviceProvider) =>
    {
        var fluentValidationSchemaProcessor = serviceProvider.CreateScope().ServiceProvider.GetService<FluentValidationSchemaProcessor>();

        // Add the fluent validations schema processor
        settings.SchemaProcessors.Add(fluentValidationSchemaProcessor);
    });

    // Add the FluentValidationSchemaProcessor as a scoped service
    serviceCollection.AddScoped<FluentValidationSchemaProcessor>(provider =>
    {
        var validationRules = provider.GetService<IEnumerable<FluentValidationRule>>();
        var loggerFactory = provider.GetService<ILoggerFactory>();

        return new FluentValidationSchemaProcessor(provider, validationRules, loggerFactory);
    });
}

Version compatibility

ZymLabs.NSwag.FluentValidation	Swashbuckle.AspNetCore	FluentValidation
[0.1.0, 0.4.0)	[13.0.0, 14.0.0)	>=7.2.0
[0.4.0, 0.5.0)	[13.0.0, 14.0.0)	>=10.0.0

Supported validators

• INotNullValidator (NotNull)
• INotEmptyValidator (NotEmpty)
• ILengthValidator (Length, MinimumLength, MaximumLength, ExactLength)
• IRegularExpressionValidator (Email, Matches)
• IComparisonValidator (GreaterThan, GreaterThanOrEqual, LessThan, LessThanOrEqual)
• IBetweenValidator (InclusiveBetween, ExclusiveBetween)

Extensibility

You can register FluentValidationRule in ServiceCollection.

User defined rule name replaces default rule with the same. Full list of default rules can be get by FluentValidationRules.CreateDefaultRules()

List or default rules:

• Required
• NotEmpty
• Length
• Pattern
• Comparison
• Between

Example of rule:

new FluentValidationRule("Pattern")
{
    Matches = propertyValidator => propertyValidator is IRegularExpressionValidator,
    Apply = context =>
    {
        var regularExpressionValidator = (IRegularExpressionValidator)context.PropertyValidator;
        context.Schema.Properties[context.PropertyKey].Pattern = regularExpressionValidator.Expression;
    }
},

Samples

Swagger Sample model and validator

public class Sample
{
    public string PropertyWithNoRules { get; set; }

    public string NotNull { get; set; }
    public string NotEmpty { get; set; }
    public string EmailAddress { get; set; }
    public string RegexField { get; set; }

    public int ValueInRange { get; set; }
    public int ValueInRangeExclusive { get; set; }

    public float ValueInRangeFloat { get; set; }
    public double ValueInRangeDouble { get; set; }
}

public class SampleValidator : AbstractValidator<Sample>
{
    public SampleValidator()
    {
        RuleFor(sample => sample.NotNull).NotNull();
        RuleFor(sample => sample.NotEmpty).NotEmpty();
        RuleFor(sample => sample.EmailAddress).EmailAddress();
        RuleFor(sample => sample.RegexField).Matches(@"(\d{4})-(\d{2})-(\d{2})");

        RuleFor(sample => sample.ValueInRange).GreaterThanOrEqualTo(5).LessThanOrEqualTo(10);
        RuleFor(sample => sample.ValueInRangeExclusive).GreaterThan(5).LessThan(10);

        RuleFor(sample => sample.ValueInRangeFloat).InclusiveBetween(1.1f, 5.3f);
        RuleFor(sample => sample.ValueInRangeDouble).ExclusiveBetween(2.2, 7.5f);
    }
}

Swagger Sample model screenshot

Validator with Include

public class CustomerValidator : AbstractValidator<Customer>
{
    public CustomerValidator()
    {
        RuleFor(customer => customer.Surname).NotEmpty();
        RuleFor(customer => customer.Forename).NotEmpty().WithMessage("Please specify a first name");

        Include(new CustomerAddressValidator());
    }
}

internal class CustomerAddressValidator : AbstractValidator<Customer>
{
    public CustomerAddressValidator()
    {
        RuleFor(customer => customer.Address).Length(20, 250);
    }
}

Upgrading

• To 0.6.0

  Update the dependency injection to specify the constructor to use as there is now ambiguity with the other constructor.

  System.InvalidOperationException
      Unable to activate type 'ZymLabs.NSwag.FluentValidation.FluentValidationSchemaProcessor'. The following constructors are ambiguous:
  
      Void .ctor(System.IServiceProvider, System.Collections.Generic.IEnumerable`1[ZymLabs.NSwag.FluentValidation.FluentValidationRule], Microsoft.Extensions.Logging.ILoggerFactory)
  
      Void .ctor(FluentValidation.IValidatorFactory, System.Collections.Generic.IEnumerable`1[ZymLabs.NSwag.FluentValidation.FluentValidationRule], Microsoft.Extensions.Logging.ILoggerFactory)
  
      at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateConstructorCallSite(ResultCache lifetime, Type serviceType, Type implementationType, CallSiteChain callSiteChain)

  From:

  serviceCollection.AddScoped<FluentValidationSchemaProcessor>();

  To:

  serviceCollection.AddScoped<FluentValidationSchemaProcessor>(provider =>
  {
      var validationRules = provider.GetService<IEnumerable<FluentValidationRule>>();
      var loggerFactory = provider.GetService<ILoggerFactory>();
  
      return new FluentValidationSchemaProcessor(provider, validationRules, loggerFactory);
  });

Credits

This project is a port of MicroElements.Swashbuckle.FluentValidation to NSwag. The initial version of this project was based on Mujahid Daud Khan answer on StackOverflow: https://stackoverflow.com/questions/44638195/fluent-validation-with-swagger-in-asp-net-core/49477995#49477995