HttpRouteBuilder - 它去了哪里,为什么？

Question

我将我的nuget包的Web API 2从RC1升级到5.0.0,并且傻眼了,发现曾经可以访问的HttpRouteBuilder是内置的.除此之外,HttpConfiguration.MapHttpAttributeRoutes不再存在重载,它将HttpRouteBuilder作为参数.为什么？

我正在使用它,它解决了我的项目中的一个主要问题.我该用什么呢？

背景:我正在编写一个使用Web API 2属性路由的服务器.我实现了一个继承自HttpRouteBuilder的类,这样我就可以为每个URI注入一些额外的路径段.例如,如果默认路由构建器最终为// myserver/user/update创建路由,则我的路由构建器会将该路由修改为// myserver/{instance}/user/update.我希望这是自动完成的,这样我就不必在我的数百个HttpGet,HttpPost等属性的每一个中都坚持这一点.那么现在我如何处理这一重大变化呢？

Answer 1

这种内部因素也破坏了我正在做的事情。

2013 年 8 月 21 日进行的更改集对api 进行了更改以解决此问题。根据该问题，删除功能的唯一原因是使 Web Api 更接近 MVC 的 api。我认为这并不是一个特别好的理由。

为了解决我的问题，我实现了一个IHttpActionSelector源自ApiControllerActionSelector. 我希望这不会是我的最终解决方案，因为对于一个简单的事情来说，代码确实太多了。这种方法也应该适用于您的问题。

在我的项目中，每个路由都需要根据在哪个程序集中找到它进行修改。在下面的简化代码中，每个路由都带有前缀/Api（在控制器之前RoutePrefixAttribute（如果存在））。

实际上IHttpActionSelector：

public class PrefixWithApiControllerActionSelector : WrappingApiControllerActionSelector {
    protected override HttpActionDescriptor WrapHttpActionDescriptor(HttpActionDescriptor actionDescriptor) {
        if (actionDescriptor is ReflectedHttpActionDescriptor)
            return new PrefixWithApiReflectedHttpActionDescriptor((ReflectedHttpActionDescriptor)actionDescriptor);
        return actionDescriptor;
    }
}

public abstract class WrappingApiControllerActionSelector : ApiControllerActionSelector {
    protected abstract HttpActionDescriptor WrapHttpActionDescriptor(HttpActionDescriptor actionDescriptor);

    public override ILookup<string, HttpActionDescriptor> GetActionMapping(HttpControllerDescriptor controllerDescriptor) {
        return base.GetActionMapping(controllerDescriptor).SelectMany(grouping => {
            return grouping.Select(actionDescriptor => new KeyValuePair<string, HttpActionDescriptor>(grouping.Key, WrapHttpActionDescriptor(actionDescriptor)));
        }).ToLookup(_ => _.Key, _ => _.Value);
    }
}

改变路线的部分：

public class PrefixWithApiHttpRouteInfoProvider : WrappedHttpRouteInfoProvider {
    public PrefixWithApiHttpRouteInfoProvider(IHttpRouteInfoProvider infoProvider, HttpControllerDescriptor controllerDescriptor) : base(infoProvider, controllerDescriptor) { }

    public override string Template {
        get {
            var parts = new List<string>();
            parts.Add("Api");

            var prefix = ControllerDescriptor.GetCustomAttributes<RoutePrefixAttribute>().FirstOrDefault();
            if (prefix != null && !string.IsNullOrEmpty(prefix.Prefix)) {
                parts.Add(prefix.Prefix);
            }

            if (!string.IsNullOrEmpty(InfoProvider.Template)) {
                parts.Add(InfoProvider.Template);
            }

            var route = "~/" + string.Join("/", parts);
            if (route.Length > 2 && route.EndsWith("/", StringComparison.Ordinal)) {
                route = route.Substring(0, route.Length - 1);
            }
            return route;
        }
    }
}

public abstract class WrappedHttpRouteInfoProvider : IHttpRouteInfoProvider {
    private readonly IHttpRouteInfoProvider _infoProvider;
    private readonly HttpControllerDescriptor _controllerDescriptor;

    protected WrappedHttpRouteInfoProvider(IHttpRouteInfoProvider infoProvider, HttpControllerDescriptor controllerDescriptor) {
        _infoProvider = infoProvider;
        _controllerDescriptor = controllerDescriptor;
    }

    public virtual string Name {
        get { return InfoProvider.Name; }
    }

    public virtual string Template {
        get { return _infoProvider.Template; }
    }

    public virtual int Order {
        get { return InfoProvider.Order; }
    }

    protected HttpControllerDescriptor ControllerDescriptor {
        get { return _controllerDescriptor; }
    }

    protected IHttpRouteInfoProvider InfoProvider {
        get { return _infoProvider; }
    }
}

胶水：

public class PrefixWithApiReflectedHttpActionDescriptor : WrappedReflectedHttpActionDescriptor {
    public PrefixWithApiReflectedHttpActionDescriptor(ReflectedHttpActionDescriptor descriptor) : base(descriptor) {}

    public override Collection<T> GetCustomAttributes<T>(bool inherit) {
        if (typeof(T) == typeof(IHttpRouteInfoProvider)) {
            var attributes = Descriptor.GetCustomAttributes<T>(inherit).Cast<IHttpRouteInfoProvider>().Select(_ => new PrefixWithApiHttpRouteInfoProvider(_, Descriptor.ControllerDescriptor));
            return new Collection<T>(attributes.Cast<T>().ToList());
        }
        return Descriptor.GetCustomAttributes<T>(inherit);
    }

    public override Collection<T> GetCustomAttributes<T>() {
        if (typeof(T) == typeof(IHttpRouteInfoProvider)) {
            var attributes = Descriptor.GetCustomAttributes<T>().Cast<IHttpRouteInfoProvider>().Select(_ => new PrefixWithApiHttpRouteInfoProvider(_, Descriptor.ControllerDescriptor));
            return new Collection<T>(attributes.Cast<T>().ToList());
        }
        return Descriptor.GetCustomAttributes<T>();
    }
}

public abstract class WrappedReflectedHttpActionDescriptor : ReflectedHttpActionDescriptor {
    private readonly ReflectedHttpActionDescriptor _descriptor;

    protected WrappedReflectedHttpActionDescriptor(ReflectedHttpActionDescriptor descriptor) : base(descriptor.ControllerDescriptor, descriptor.MethodInfo) {
        _descriptor = descriptor;
    }

    public override HttpActionBinding ActionBinding {
        get { return Descriptor.ActionBinding; }
        set { Descriptor.ActionBinding = value; }
    }

    public override Collection<T> GetCustomAttributes<T>(bool inherit) {
        return Descriptor.GetCustomAttributes<T>(inherit);
    }

    public override Collection<T> GetCustomAttributes<T>() {
        return Descriptor.GetCustomAttributes<T>();
    }

    public override Collection<System.Web.Http.Filters.FilterInfo> GetFilterPipeline() {
        return Descriptor.GetFilterPipeline();
    }

    public override Collection<System.Web.Http.Filters.IFilter> GetFilters() {
        return Descriptor.GetFilters();
    }

    public override System.Collections.Concurrent.ConcurrentDictionary<object, object> Properties {
        get { return Descriptor.Properties; }
    }

    public override IActionResultConverter ResultConverter {
        get { return Descriptor.ResultConverter; }
    }

    public override Collection<HttpMethod> SupportedHttpMethods {
        get { return Descriptor.SupportedHttpMethods; }
    }

    public override Collection<HttpParameterDescriptor> GetParameters() {
        return Descriptor.GetParameters();
    }

    public override Task<object> ExecuteAsync(HttpControllerContext controllerContext, IDictionary<string, object> arguments, CancellationToken cancellationToken) {
        return Descriptor.ExecuteAsync(controllerContext, arguments, cancellationToken);
    }

    public override string ActionName {
        get { return Descriptor.ActionName; }
    }

    public override Type ReturnType {
        get { return Descriptor.ReturnType; }
    }

    protected ReflectedHttpActionDescriptor Descriptor {
        get { return _descriptor; }
    }
}

要使用此功能，只需在配置中替换该IHttpActionSelector服务即可。PrefixWithApiControllerActionSelector

如果您找到更干净的做事方式，请发布您的解决方案！