ApiExplorer无法识别具有自定义类型的路由属性 [英] ApiExplorer does not recognize route attributes with custom type

问题描述

我有一个项目，我想在其中使用具有自定义类型的路由属性. 我将自定义类型用作查询参数的以下代码可以正常工作，并且帮助页面显示该自定义类型.

I have a project where I want to use route attributes with a custom type. The following code where I have the custom type as a query parameter works fine and the help page displays the custom type.

// GET api/values?5,6
[Route("api/values")]
public string Get(IntegerListParameter ids)
{
    return "value";
}

WebApi.HelpPage提供以下文档 帮助:页面

WebApi.HelpPage gives the following documentation Help:Page

如果我更改代码以使用路由属性，结果是我得到一个空的帮助页面.

If I change the code to use route attributes, the result is that I get an empty help page.

// GET api/values/5,6
[Route("api/values/{ids}")]
public string Get(IntegerListParameter ids)
{
    return "value";
}

当我检查在HelpController.cs中观察到的代码时，ApiExplorer.ApiDescriptions返回一个空的ApiDescriptions集合

When I inspect the code I observe in HelpController.cs that ApiExplorer.ApiDescriptions returns an empty collection of ApiDescriptions

public ActionResult Index()
{
    ViewBag.DocumentationProvider = Configuration.Services.GetDocumentationProvider();
    Collection<ApiDescription> apiDescriptions = Configuration.Services.GetApiExplorer().ApiDescriptions;

    return View(apiDescriptions);
}

有什么办法让ApiExplorer将我的自定义类IntegerListParameter识别为属性路由?

Is there any way to get ApiExplorer to recognize my custom class IntegerListParameter as attribute routing?

推荐答案

您需要:

1. 为您的IntegerListParameter类型添加HttpParameterBinding
2. 将绑定标记为IValueProviderParameterBinding并实现ValueProviderFactories
3. 为IntegerListParameter添加一个转换器，并为typeof(string)参数覆盖CanConvertFrom方法

1. add HttpParameterBinding for your IntegerListParameter type
2. mark the binding as IValueProviderParameterBinding and implement ValueProviderFactories
3. add a converter for IntegerListParameter and override CanConvertFrom method for typeof(string) parameter

执行这些操作后，必须在ApiExplorer中识别具有自定义类型IntegerListParameter的路由.

After these actions, route with custom type IntegerListParameter must be recognized in ApiExplorer.

请参阅示例ObjectId的示例:

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        //...
        config.ParameterBindingRules.Insert(0, GetCustomParameterBinding);
        TypeDescriptor.AddAttributes(typeof(ObjectId), new TypeConverterAttribute(typeof(ObjectIdConverter)));
        //...
    }

    public static HttpParameterBinding GetCustomParameterBinding(HttpParameterDescriptor descriptor)
    {
        if (descriptor.ParameterType == typeof(ObjectId))
        {
            return new ObjectIdParameterBinding(descriptor);
        }
        // any other types, let the default parameter binding handle
        return null;
    }
}

public class ObjectIdParameterBinding : HttpParameterBinding, IValueProviderParameterBinding
{
    public ObjectIdParameterBinding(HttpParameterDescriptor desc)
        : base(desc)
    {
    }

    public override Task ExecuteBindingAsync(ModelMetadataProvider metadataProvider, HttpActionContext actionContext, CancellationToken cancellationToken)
    {
        try
        {
            SetValue(actionContext, new ObjectId(actionContext.ControllerContext.RouteData.Values[Descriptor.ParameterName] as string));
            return Task.CompletedTask;
        }
        catch (FormatException)
        {
            throw new BadRequestException("Invalid id format");
        }
    }

    public IEnumerable<ValueProviderFactory> ValueProviderFactories { get; } = new[] { new QueryStringValueProviderFactory() };
}

public class ObjectIdConverter : TypeConverter
{
    public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
    {
        if (sourceType == typeof(string))
            return true;
        return base.CanConvertFrom(context, sourceType);
    }
}

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