ASP.NET核心MVC混合路由/ FromBody模型绑定和验证

Question

我正在使用ASP.NET Core 1.1 MVC来构建JSON API.给出以下模型和动作方法:

public class TestModel
{
    public int Id { get; set; }

    [Range(100, 999)]
    public int RootId { get; set; }

    [Required, MaxLength(200)]
    public string Name { get; set; }

    public string Description { get; set; }
}

[HttpPost("/test/{rootId}/echo/{id}")]
public IActionResult TestEcho([FromBody] TestModel data)
{
    return Json(new
    {
        data.Id,
        data.RootId,
        data.Name,
        data.Description,
        Errors = ModelState.IsValid ? null : ModelState.SelectMany(x => x.Value.Errors)
    });
}

在[FromBody]我的动作方法的参数导致必须从发布到端点JSON有效载荷的约束的模型,然而,它也可以防止Id和RootId属性经由路由参数的约束.

我可以将其分解为单独的模型,一个绑定路由,一个绑定到正文,或者我也可以强制任何客户端发送id&rootId作为有效负载的一部分,但这两个解决方案似乎比我更复杂.我喜欢并且不允许我将验证逻辑保存在一个地方.有没有办法让这种情况适用于模型可以正确绑定的地方,我可以将我的模型和验证逻辑保持在一起？

Answer 1

您可以删除[FromBody]输入上的装饰器,让MVC绑定映射属性:

[HttpPost("/test/{rootId}/echo/{id}")]
public IActionResult TestEcho(TestModel data)
{
    return Json(new
    {
        data.Id,
        data.RootId,
        data.Name,
        data.Description,
        Errors = ModelState.IsValid ? null : ModelState.SelectMany(x => x.Value.Errors)
    });
}

更多信息: ASP.NET Core MVC中的模型绑定

UPDATE

测试

更新2

@heavyd,你是对的,JSON数据需要[FromBody]属性来绑定你的模型.所以我上面说的将用于表单数据,但不用于JSON数据.

或者,您可以创建一个自定义模型绑定器,用于绑定url中的Id和RootId属性,同时绑定请求主体中的其余属性.

public class TestModelBinder : IModelBinder
{
    private BodyModelBinder defaultBinder;

    public TestModelBinder(IList<IInputFormatter> formatters, IHttpRequestStreamReaderFactory readerFactory) // : base(formatters, readerFactory)
    {
        defaultBinder = new BodyModelBinder(formatters, readerFactory);
    }

    public async Task BindModelAsync(ModelBindingContext bindingContext)
    {
        // callinng the default body binder
        await defaultBinder.BindModelAsync(bindingContext);

        if (bindingContext.Result.IsModelSet)
        {
            var data = bindingContext.Result.Model as TestModel;
            if (data != null)
            {
                var value = bindingContext.ValueProvider.GetValue("Id").FirstValue;
                int intValue = 0;
                if (int.TryParse(value, out intValue))
                {
                    // Override the Id property
                    data.Id = intValue;
                }
                value = bindingContext.ValueProvider.GetValue("RootId").FirstValue;
                if (int.TryParse(value, out intValue))
                {
                    // Override the RootId property
                    data.RootId = intValue;
                }
                bindingContext.Result = ModelBindingResult.Success(data);
            }

        }

    }
}

创建活页夹提供者:

public class TestModelBinderProvider : IModelBinderProvider
{
    private readonly IList<IInputFormatter> formatters;
    private readonly IHttpRequestStreamReaderFactory readerFactory;

    public TestModelBinderProvider(IList<IInputFormatter> formatters, IHttpRequestStreamReaderFactory readerFactory)
    {
        this.formatters = formatters;
        this.readerFactory = readerFactory;
    }

    public IModelBinder GetBinder(ModelBinderProviderContext context)
    {
        if (context.Metadata.ModelType == typeof(TestModel))
            return new TestModelBinder(formatters, readerFactory);

        return null;
    }
}

并告诉MVC使用它:

services.AddMvc()
  .AddMvcOptions(options =>
  {
     IHttpRequestStreamReaderFactory readerFactory = services.BuildServiceProvider().GetRequiredService<IHttpRequestStreamReaderFactory>();
     options.ModelBinderProviders.Insert(0, new TestModelBinderProvider(options.InputFormatters, readerFactory));
  });

然后你的控制器有:

[HttpPost("/test/{rootId}/echo/{id}")]
public IActionResult TestEcho(TestModel data)
{...}

测试

您可以添加一个Id和RootId您的JSON,但它们将被忽略,因为我们在模型绑定器中覆盖它们.

更新3

以上允许您使用数据模型注释进行验证Id和RootId.但我认为可能会混淆其他开发人员,他们会查看您的API代码.我建议只是简化API签名以接受不同的模型使用[FromBody]并分离来自uri的其他两个属性.

[HttpPost("/test/{rootId}/echo/{id}")]
public IActionResult TestEcho(int id, int rootId, [FromBody]TestModelNameAndAddress testModelNameAndAddress)

你可以为你的所有输入找到一个验证器,例如:

// This would return a list of tuples of property and error message.
var errors = validator.Validate(id, rootId, testModelNameAndAddress); 
if (errors.Count() > 0)
{
    foreach (var error in errors)
    {
        ModelState.AddModelError(error.Property, error.Message);
    }
}

Answer 2

在研究之后,我想出了一个创建新模型绑定器+绑定源+属性的解决方案,它结合了BodyModelBinder和ComplexTypeModelBinder的功能.它首先使用BodyModelBinder从body读取,然后ComplexModelBinder填充其他字段.代码在这里:

public class BodyAndRouteBindingSource : BindingSource
{
    public static readonly BindingSource BodyAndRoute = new BodyAndRouteBindingSource(
        "BodyAndRoute",
        "BodyAndRoute",
        true,
        true
        );

    public BodyAndRouteBindingSource(string id, string displayName, bool isGreedy, bool isFromRequest) : base(id, displayName, isGreedy, isFromRequest)
    {
    }

    public override bool CanAcceptDataFrom(BindingSource bindingSource)
    {
        return bindingSource == Body || bindingSource == this;
    }
}

[AttributeUsage(AttributeTargets.Parameter | AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
public class FromBodyAndRouteAttribute : Attribute, IBindingSourceMetadata
{
    public BindingSource BindingSource => BodyAndRouteBindingSource.BodyAndRoute;
}

public class BodyAndRouteModelBinder : IModelBinder
{
    private readonly IModelBinder _bodyBinder;
    private readonly IModelBinder _complexBinder;

    public BodyAndRouteModelBinder(IModelBinder bodyBinder, IModelBinder complexBinder)
    {
        _bodyBinder = bodyBinder;
        _complexBinder = complexBinder;
    }

    public async Task BindModelAsync(ModelBindingContext bindingContext)
    {
        await _bodyBinder.BindModelAsync(bindingContext);

        if (bindingContext.Result.IsModelSet)
        {
            bindingContext.Model = bindingContext.Result.Model;
        }

        await _complexBinder.BindModelAsync(bindingContext);
    }
}

public class BodyAndRouteModelBinderProvider : IModelBinderProvider
{
    private BodyModelBinderProvider _bodyModelBinderProvider;
    private ComplexTypeModelBinderProvider _complexTypeModelBinderProvider;

    public BodyAndRouteModelBinderProvider(BodyModelBinderProvider bodyModelBinderProvider, ComplexTypeModelBinderProvider complexTypeModelBinderProvider)
    {
        _bodyModelBinderProvider = bodyModelBinderProvider;
        _complexTypeModelBinderProvider = complexTypeModelBinderProvider;
    }

    public IModelBinder GetBinder(ModelBinderProviderContext context)
    {
        var bodyBinder = _bodyModelBinderProvider.GetBinder(context);
        var complexBinder = _complexTypeModelBinderProvider.GetBinder(context);

        if (context.BindingInfo.BindingSource != null
            && context.BindingInfo.BindingSource.CanAcceptDataFrom(BodyAndRouteBindingSource.BodyAndRoute))
        {
            return new BodyAndRouteModelBinder(bodyBinder, complexBinder);
        }
        else
        {
            return null;
        }
    }
}

public static class BodyAndRouteModelBinderProviderSetup
{
    public static void InsertBodyAndRouteBinding(this IList<IModelBinderProvider> providers)
    {
        var bodyProvider = providers.Single(provider => provider.GetType() == typeof(BodyModelBinderProvider)) as BodyModelBinderProvider;
        var complexProvider = providers.Single(provider => provider.GetType() == typeof(ComplexTypeModelBinderProvider)) as ComplexTypeModelBinderProvider;

        var bodyAndRouteProvider = new BodyAndRouteModelBinderProvider(bodyProvider, complexProvider);

        providers.Insert(0, bodyAndRouteProvider);
    }
}

Answer 3

1. 安装包HybridModelBinding

2. 添加到Statrup:

   services.AddMvc()
       .AddHybridModelBinder();
   

3. 模型:

   public class Person
   {
       public int Id { get; set; }
       public string Name { get; set; }
       public string FavoriteColor { get; set; }
   }
   

4. 控制器:

   [HttpPost]
   [Route("people/{id}")]
   public IActionResult Post([FromHybrid]Person model)
   { }
   

5. 请求:

   curl -X POST -H "Accept: application/json" -H "Content-Type:application/json" -d '{
       "id": 999,
       "name": "Bill Boga",
       "favoriteColor": "Blue"
   }' "https://localhost/people/123?name=William%20Boga"
   

6. 结果:

   {
       "Id": 123,
       "Name": "William Boga",
       "FavoriteColor": "Blue"
   }
   

7. 还有其他高级功能.