Asp.net core 学习笔记 Fluent Validation

2020-02-20

NotEmpty vs NotNull

public class SimpleTestData
{
    public string? string1 { get; set; }
    public string string2 { get; set; } = "";
    public int? number1 { get; set; }
    public int numbe2 { get; set; }
}

json

{
    "string1" : "",
    "string2" : "",
    "number1" : 0,
    "number2" : 0
}

result

"errors": {
    "numbe2": [
      "'numbe2' must not be empty."
    ],
    "string1": [
      "'string1' must not be empty."
    ],
    "string2": [
      "'string2' must not be empty."
    ]
  }

int 如果是 nullable 的话, empty 只是验证 != null, 0 是 ok 的, 因为 default(int?) 是 null. 符合逻辑.

int 如果不是 nullable, empty 验证 != 0 因为 default(int) 是 0

但是 string 就不同了, 因为没有初始值, 所以 emptty 永远都会检查 "" empty string. 所以这个时候用 notnull 就比较合理了.

not empty 对 List<string> length = 0 也是会保护哦

2020-02-04

InclusiveBetween vs ExclusiveBetween

between 1 - 10， 没有说明 1 和 10 是不是 ok. (大部分情况下是)

如果 1 和 10 ok 那么就是 InclusiveBetween

如果是 1 和 10 不可以, 2...9 才可以的话，那么是 ExclusiveBetween

2019-10-24

新功能，child validation

从前需要特地开一个 child validator 来写逻辑, 现在不需要咯

public class CustomerValidator : AbstractValidator<Customer> {
  public CustomerValidator() {
    RuleForEach(x => x.Orders).ChildRules(order => {
      order.RuleFor(x => x.ProductName).NotNull();
      order.RuleFor(x => x.Amount).GreaterThan();
    });
  }
}

2019-08-18

验证 decimal scale 和 precision

RuleFor(x => x.Amount).ScalePrecision(4, 9);

留意哦，1st param 是 scale 2nd 才是 precision

和 sql 是相反的. sql 是 decimal(9,4), 真奇葩...

issue : https://github.com/JeremySkinner/FluentValidation/issues/1008

目前它的验证也和 sql 不同, 比如 decimal(9, 4), 意思是前面最多 5 位数. 但是 fluent validation 没有左右验证的概念. 所以这个是通过的，然后你输入 sql 就会报错了.

作者说 9.0 可能修改这个. 让它和 sql 验证行为一致.

之前就有在 .net 时代介绍过了.

这个 dll 也支持 .net core 而且一直有人维护.

对比 data annotation 的 validation, 我越来越觉得这个 fluent 好用多了.

一堆 Attribute 在 property 上面真的很乱.

安装很容易

nuget : https://www.nuget.org/packages/FluentValidation.AspNetCore/

然后 startup.cs

  services.AddMvc().AddFluentValidation(fvc => fvc.RegisterValidatorsFromAssemblyContaining<Startup>()).SetCompatibilityVersion(CompatibilityVersion.Version_2_2);

定义规则 : getting started refer : https://fluentvalidation.net/start

        public class ProductPostData
        {
            public string code { get; set; }
        }

        public class ProductPostDataValidator : AbstractValidator<ProductPostData>
        {
            public ProductPostDataValidator()
            {
                RuleFor(product => product.code).NotEmpty();
            }
        }

build in rule ：

https://fluentvalidation.net/built-in-validators

complex 的做法 ：

写一个 child validator, 然后 SetValidator. 一定要 set 哦, 不会自动的

RuleFor(o => o.Address).NotNull();
RuleFor(o => o.Address).SetValidator(new AddressValidator());

或者直接定义, 不过要记得另外处理 null 的情况哦, 还有一般的 If

RuleFor(o => o.Address).NotNull();
RuleFor(o => o.Address.text1).NotEmpty().When(o => o.Address != null);

也可以 if else 包起来

When(customer => customer.IsPreferred, () => {
   RuleFor(customer => customer.CustomerDiscount).GreaterThan();
   RuleFor(customer => customer.CreditCardNumber).NotNull();
}).Otherwise(() => {
  RuleFor(customer => customer.CustomerDiscount).Equal();
});

这个很常用到 .Must()

refer : https://fluentvalidation.net/custom-validators#predicate-validator

custom valid

https://fluentvalidation.net/custom-validators

namespace Project.Validators
{
    public static class CustomValidatorExtensions
    {
        public static IRuleBuilderOptions<T, string> IsKeatKeat<T>(
            this IRuleBuilder<T, string> ruleBuilder, string value)
        {

            return ruleBuilder.Must((rootObject, propertyValue, context) =>
            {
                context.MessageFormatter.AppendArgument("value", value);
                return (propertyValue as string) == "keatkeat";
            }).WithMessage("{PropertyValue} is not keatkeat {value}");

            //return ruleBuilder.SetValidator(new IsKeatKeatValidator(value));
        }
    }

    public class IsKeatKeatValidator : PropertyValidator
    {
        private readonly string Value;
        public IsKeatKeatValidator(string value)
               : base("{PropertyValue} is not keatkeat {value}")
        {
            Value = value;
        }
        protected override bool IsValid(PropertyValidatorContext context)
        {
            if (context.PropertyValue == null) return false;
            var propertyValue = context.PropertyValue as string;
            context.MessageFormatter.AppendArgument("value", Value);
            return propertyValue == "keatkeat";
        }
    }
}

RuleFor(p => p.code).NotEmpty().IsKeatKeat("keatkeat");

DI 和 async

public ProductPostDataValidator(
    ApplicationDbContext Db
)
{
    //RuleFor(p => p.code).NotEmpty().IsKeatKeat("keatkeat");
    RuleFor(p => p.code).NotEmpty().MustAsync(async (id, cancellation) =>
    {
        var products =  await Db.Products.ToListAsync();
        return true;
    });
}

如果用 setValidator 那就要自己传进去了。

多一个例子, 不用匿名方法

public class SimpleTestDataValidator : AbstractValidator<SimpleTestData>
{
    private readonly IHttpContextAccessor HttpContextAccessor;
    public SimpleTestDataValidator(
        IHttpContextAccessor httpContextAccessor
    )
    {
        HttpContextAccessor = httpContextAccessor;
        RuleFor(p => p.age).NotEmpty().MustAsync(BeSomething);
    }

    private async Task<bool> BeSomething(int age, CancellationToken cancellation)
    {
        await Task.Delay();
        return true;
    }
}

array, not empty 就是 check null 和 count, 通过 foreach set 后面的

 RuleFor(p => p.colors).NotEmpty().ForEach(c => c.SetValidator(new ProductColorPostDataValidator()));

错一个就停 CascadeMode, defualt 行为是会验证所有的错误.

refer https://fluentvalidation.net/start#setting-the-cascade-mode#setting-the-cascade-mode

RuleFor(p => p.age).NotEmpty();
RuleFor(p => p.age).Cascade(CascadeMode.StopOnFirstFailure).Must(BeSomething).MustAsync(BeSomethingAsync);

DependentRules 这个也是用于错就不要跑接下来的

RuleFor(p => p.name).NotEmpty();
RuleFor(p => p.datas).NotEmpty().DependentRules(() =>
{
    RuleForEach(p => p.datas).SetValidator(new DataValidator()).DependentRules(() =>
    {
        RuleFor(p => p.datas).Must(v => false);
    });
});

也可以针对整个 validator 

public class PersonValidator : AbstractValidator<Person> {
  public PersonValidator() {
    // First set the cascade mode
    CascadeMode = CascadeMode.StopOnFirstFailure;

    RuleFor(x => x.Surname).NotNull().NotEqual("foo");
    RuleFor(x => x.Forename).NotNull().NotEqual("foo");
  }
}

甚至是全局 ( 注意这个是 static 属性来的，不需要通过 config options 来配置 )

ValidatorOptions.CascadeMode = CascadeMode.StopOnFirstFailure;