Statuses

Supporting the project

Usage

1. Minimal API

MinimalApi.csproj

<ProjectSdk="Microsoft.NET.Sdk.Web">    <PropertyGroup>        <TargetFramework>net7.0</TargetFramework>        <Nullable>enable</Nullable>        <ImplicitUsings>enable</ImplicitUsings>    </PropertyGroup>    <ItemGroup>        <PackageReferenceInclude="FluentValidation.AspNetCore"Version="11.2.2" />        <PackageReferenceInclude="MicroElements.Swashbuckle.FluentValidation"Version="6.0.0" />        <PackageReferenceInclude="Microsoft.AspNetCore.OpenApi"Version="7.0.2" />        <PackageReferenceInclude="Swashbuckle.AspNetCore"Version="6.4.0" />    </ItemGroup>    </Project>

Program.cs

usingFluentValidation;usingFluentValidation.AspNetCore;usingMicroElements.Swashbuckle.FluentValidation.AspNetCore;varbuilder=WebApplication.CreateBuilder(args);varservices=builder.Services;// Asp.Net stuffservices.AddControllers();services.AddEndpointsApiExplorer();// Add Swaggerservices.AddSwaggerGen();// Add FVservices.AddFluentValidationAutoValidation();services.AddFluentValidationClientsideAdapters();// Add FV validatorsservices.AddValidatorsFromAssemblyContaining<Program>();// Add FV Rules to swaggerservices.AddFluentValidationRulesToSwagger();varapp=builder.Build();// Use Swaggerapp.UseSwagger();app.UseSwaggerUI();app.MapControllers();app.Run();

2. AspNetCore WebApi

Reference packages in your web project

<PackageReferenceInclude="FluentValidation.AspNetCore"Version="11.1.0" /><PackageReferenceInclude="MicroElements.Swashbuckle.FluentValidation"Version="6.0.0" /><PackageReferenceInclude="Swashbuckle.AspNetCore"Version="6.3.0" />

Change Startup.cs

// This method gets called by the runtime. Use this method to add services to the container.publicvoidConfigureServices(IServiceCollectionservices){// Asp.net stuffservices.AddControllers();// HttpContextValidatorRegistry requires access to HttpContextservices.AddHttpContextAccessor();// Register FV validatorsservices.AddValidatorsFromAssemblyContaining<Startup>(lifetime:ServiceLifetime.Scoped);// Add FV to Asp.netservices.AddFluentValidationAutoValidation();// Add swaggerservices.AddSwaggerGen(c=>{c.SwaggerDoc("v1",newOpenApiInfo{Title="My API",Version="v1"});});// [Optional] Add INameResolver (SystemTextJsonNameResolver will be registered by default)// services.AddSingleton<INameResolver, CustomNameResolver>();// Adds FluentValidationRules staff to Swagger. (Minimal configuration)services.AddFluentValidationRulesToSwagger();// [Optional] Configure generation options for your needs. Also can be done with services.Configure<SchemaGenerationOptions>// services.AddFluentValidationRulesToSwagger(options =>// {//     options.SetNotNullableIfMinLengthGreaterThenZero = true;//     options.UseAllOffForMultipleRules = true;// });// Adds loggingservices.AddLogging(builder=>builder.AddConsole());}// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.publicvoidConfigure(IApplicationBuilderapp,IHostingEnvironmentenv){app.UseRouting();app.UseEndpoints(endpoints=>{endpoints.MapControllers();});// Adds swaggerapp.UseSwagger();// Adds swagger UIapp.UseSwaggerUI(c=>{c.SwaggerEndpoint("/swagger/v1/swagger.json","My API V1");});}

Version compatibility

Sample application

Supported validators

Extensibility

newFluentValidationRule("Pattern"){Matches= propertyValidator=>propertyValidatorisIRegularExpressionValidator,Apply= context=>{varregularExpressionValidator=(IRegularExpressionValidator)context.PropertyValidator;context.Schema.Properties[context.PropertyKey].Pattern=regularExpressionValidator.Expression;}},

Samples

Swagger Sample model and validator

publicclassSample{publicstringPropertyWithNoRules{get;set;}publicstringNotNull{get;set;}publicstringNotEmpty{get;set;}publicstringEmailAddress{get;set;}publicstringRegexField{get;set;}publicintValueInRange{get;set;}publicintValueInRangeExclusive{get;set;}publicfloatValueInRangeFloat{get;set;}publicdoubleValueInRangeDouble{get;set;}}publicclassSampleValidator:AbstractValidator<Sample>{publicSampleValidator(){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);// WARNING: Swashbuckle implements minimum and maximim as int so you will loss fraction part of float and double numbersRuleFor(sample=>sample.ValueInRangeFloat).InclusiveBetween(1.1f,5.3f);RuleFor(sample=>sample.ValueInRangeDouble).ExclusiveBetween(2.2,7.5f);}}

Swagger Sample model screenshot

Validator with Include

publicclassCustomerValidator:AbstractValidator<Customer>{publicCustomerValidator(){RuleFor(customer=>customer.Surname).NotEmpty();RuleFor(customer=>customer.Forename).NotEmpty().WithMessage("Please specify a first name");Include(newCustomerAddressValidator());}}internalclassCustomerAddressValidator:AbstractValidator<Customer>{publicCustomerAddressValidator(){RuleFor(customer=>customer.Address).Length(20,250);}}

Get params bounded to validatable models

Defining rules dynamically from database

Common problems and workarounds

Error:System.InvalidOperationException: 'Cannot resolve 'IValidator<T>' from root provider because it requires scoped service 'TDependency'

Workaround 1 (Use HttpContextServiceProviderValidatorFactory) by @WarpSpideR

publicvoidConfigureServices(IServiceCollectionservices){// HttpContextServiceProviderValidatorFactory requires access to HttpContextservices.AddHttpContextAccessor();services.AddMvc()// 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);});

Workaround 2 (Use ScopedSwaggerMiddleware)

publicvoidConfigure(IApplicationBuilderapp,IHostingEnvironmentenv){app.UseMvc()// Use scoped swagger if you have problems with scoped services in validators.UseScopedSwagger();

Workaround 3 (Set ValidateScopes to false)

publicstaticIWebHostBuildWebHost(string[]args)=>WebHost.CreateDefaultBuilder(args)// Needed for using scoped services (for example DbContext) in validators.UseDefaultServiceProvider(options=>options.ValidateScopes=false).UseStartup<Startup>().Build();

Problem: I cant use several validators of one type

Problem: I'm usingFluentValidation orFluentValidation.DependencyInjectionExtensions instead ofFluentValidation.AspNetCore

services.TryAddTransient<IValidatorFactory,ServiceProviderValidatorFactory>();services.AddFluentValidationRulesToSwagger();

Problem: Newtonsoft.Json DefaultNamingStrategy, SnakeCaseNamingStrategy does not work

Startup.cs:.AddJsonOptions(options=>{options.JsonSerializerOptions.PropertyNamingPolicy=newNewtonsoftJsonNamingPolicy(newSnakeCaseNamingStrategy());//options.JsonSerializerOptions.DictionaryKeyPolicy = new NewtonsoftJsonNamingPolicy(new SnakeCaseNamingStrategy());})/// <summary>/// Allows use Newtonsoft <see cref="NamingStrategy"/> as System.Text <see cref="JsonNamingPolicy"/>./// </summary>publicclassNewtonsoftJsonNamingPolicy:JsonNamingPolicy{privatereadonlyNamingStrategy_namingStrategy;/// <summary>/// Creates new instance of <see cref="NewtonsoftJsonNamingPolicy"/>./// </summary>/// <param name="namingStrategy">Newtonsoft naming strategy.</param>publicNewtonsoftJsonNamingPolicy(NamingStrategynamingStrategy){_namingStrategy=namingStrategy;}/// <inheritdoc />publicoverridestringConvertName(stringname){return_namingStrategy.GetPropertyName(name,false);}}

Credits