MVC5爲WebAPI添加命名空間的支持

時間 2019-11-13

標籤 mvc5 mvc webapi 添加命名空間支持简体版

原文原文鏈接

前言

默認狀況下，微軟提供的MVC框架模板中，WebAPI路由是不支持Namespace參數的。這致使一些比較大型的項目，沒法把WebApi分離到單獨的類庫中。 html

本文將提供解決該問題的方案。 api

微軟官方曾經給出過一個關於WebAPI支持Namespace的擴展，其主要內容就是自定義實現了IHttpControllerSelector接口，經過路由配置時替換掉MVC中自帶的DefaultHttpControllerSelector達到WebAPI支持Namespace的目的。可是通過個人測試，效果並很差。這就就不貼微軟官方的源碼了。框架

解決方案

下面我介紹一下個人解決方案。 ide

首先看一下我自定義的目錄結構，以下圖： 測試

首先定義一個類，名字能夠隨意，我這裏命名爲ZhuSirNamespaceHttpControllerSelector，他繼承自MVC框架默認的DefaultHttpControllerSelector類，該繼承類主要目的是在請求URI到達WebAPI路由時檢索咱們指定的命名空間的WebAPI控制器。下面是ZhuSirNamespaceHttpControllerSelector類的源代碼，可直接複製到你本身的項目中就能夠用： this

/// <summary>
    /// 擴展自DefaultHttpControllerSelector類的控制器選擇器，目前在用
    /// </summary>
    public class ZhuSirNamespaceHttpControllerSelector : DefaultHttpControllerSelector
    {
        private const string NamespaceRouteVariableName = "namespaces";
        private readonly HttpConfiguration _configuration;
        private readonly Lazy<ConcurrentDictionary<string, Type>> _apiControllerCache;

        public ZhuSirNamespaceHttpControllerSelector(HttpConfiguration configuration)
            : base(configuration)
        {
            _configuration = configuration;
            _apiControllerCache = new Lazy<ConcurrentDictionary<string, Type>>(
                new Func<ConcurrentDictionary<string, Type>>(InitializeApiControllerCache));
        }

        private ConcurrentDictionary<string, Type> InitializeApiControllerCache()
        {
            IAssembliesResolver assembliesResolver = this._configuration.Services.GetAssembliesResolver();
            var types = this._configuration.Services.GetHttpControllerTypeResolver()
                .GetControllerTypes(assembliesResolver).ToDictionary(t => t.FullName, t => t);

            return new ConcurrentDictionary<string, Type>(types);
        }

        public IEnumerable<string> GetControllerFullName(HttpRequestMessage request, string controllerName)
        {
            object namespaceName;
            var data = request.GetRouteData();
            IEnumerable<string> keys = _apiControllerCache.Value.ToDictionary<KeyValuePair<string, Type>, string, Type>(t => t.Key,
                    t => t.Value, StringComparer.CurrentCultureIgnoreCase).Keys.ToList();

            if (!data.Values.TryGetValue(NamespaceRouteVariableName, out namespaceName))
            {
                return from k in keys
                       where k.EndsWith(string.Format(".{0}{1}", controllerName,
                       DefaultHttpControllerSelector.ControllerSuffix), StringComparison.CurrentCultureIgnoreCase)
                       select k;
            }

            string[] namespaces = (string[])namespaceName;
            return from n in namespaces
                   join k in keys on string.Format("{0}.{1}{2}", n, controllerName,
                   DefaultHttpControllerSelector.ControllerSuffix).ToLower() equals k.ToLower()
                   select k;
        }

        public override HttpControllerDescriptor SelectController(HttpRequestMessage request)
        {
            Type type;
            if (request == null)
            {
                throw new ArgumentNullException("request");
            }
            string controllerName = this.GetControllerName(request);
            if (string.IsNullOrEmpty(controllerName))
            {
                throw new HttpResponseException(request.CreateErrorResponse(HttpStatusCode.NotFound,
                    string.Format("沒法經過API路由匹配到您所請求的URI '{0}'",
                    new object[] { request.RequestUri })));
            }
            IEnumerable<string> fullNames = GetControllerFullName(request, controllerName);
            if (fullNames.Count() == 0)
            {
                throw new HttpResponseException(request.CreateErrorResponse(HttpStatusCode.NotFound,
                        string.Format("沒法經過API路由匹配到您所請求的URI '{0}'",
                        new object[] { request.RequestUri })));
            }

            if (this._apiControllerCache.Value.TryGetValue(fullNames.First(), out type))
            {
                return new HttpControllerDescriptor(_configuration, controllerName, type);
            }
            throw new HttpResponseException(request.CreateErrorResponse(HttpStatusCode.NotFound,
                string.Format("沒法經過API路由匹配到您所請求的URI '{0}'",
                new object[] { request.RequestUri })));
        }
    }

第二步，須要咱們配置WebAPI路由設置，添加{ namespaces }片斷變量，同時也能夠直接爲其設置默認值，而後替換掉原MVC框架中的DefaultHttpControllerSelector選額器爲咱們以前擴展的ZhuSirNamespaceHttpControllerSelector選額器。這裏須要注意片斷變量的變量名namespaces必定要與咱們ZhuSirNamespaceHttpControllerSelector中定義的NamespaceRouteVariableName字符串常量的值一致。下面貼出WebApiConfig的源碼:

public static class WebApiConfig
    {
        public static void Register(HttpConfiguration config)
        {
            //配置檢查Api控制後綴爲ApiController
            //var suffix = typeof(MicrosoftNamespaceHttpControllerSelector)
            //    .GetField("ControllerSuffix", BindingFlags.Static | BindingFlags.Public);
            //if (suffix != null)
            //{
            //    suffix.SetValue(null, "ApiController");
            //}

            // Web API 配置和服務
            // 將 Web API 配置爲僅使用不記名令牌身份驗證。
            config.SuppressDefaultHostAuthentication();
            config.Filters.Add(new HostAuthenticationFilter(OAuthDefaults.AuthenticationType));

            // 對 JSON 數據使用混合大小寫。
            config.Formatters.JsonFormatter.SerializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver();

            // Web API 路由
            config.MapHttpAttributeRoutes();


            config.Routes.MapHttpRoute(
                name: "DefaultApi",
                routeTemplate: "api/{controller}/{id}/{namespaces}",
                defaults: new { id = RouteParameter.Optional ,namespaces = new[] { "ZhuSir.HMS.WebApi.ApiControllers" }  }
            );

            config.Services.Replace(typeof(IHttpControllerSelector), new ZhuSirNamespaceHttpControllerSelector(config));
        }
    }

如上源碼。咱們替換了原MVC框架的DefaultHttpControllerSelector爲ZhuSirNamespaceHttpControllerSelector，而且指定了默認的namespaces爲ZhuSir.HMS.WebApi.ApiControllers。大致意思就是當URL爲 http://XXX/api/testApi時，WebApi路由將在ZhuSir.HMS.WebApi.ApiControllers命名空間下尋找名稱爲testApi的WebAPI控制器的Get方法。 spa

固然，WebAPI控制器除了集成字ApiController意外還要注意命名規範，都須要以Controller結尾，爲了避免讓API控制器與MVC控制器重名，我都以ApiController結尾。下面貼出testAPI的源碼：code

namespace ZhuSir.HMS.WebApi.ApiControllers
{
    public class TestApiController : ApiController
    {
        [HttpGet]
        public string Gettest()
        {
            return "測試數據";
        }
    }
}