HttpControllerDescriptor與HttpActionDescriptor
HttpControllerDescriptor封裝了某個HttpController類型的元數據,我們可以將它視為某個HttpController類型的描述對象。HttpActionDescriptor也類似。上一篇中說到Abp將ApiControler與Action信息分別封裝於DynamicApiControllerInfo,DynamicApiActionInfo。Abp種HttpControllerDescriptor與HttpActionDescriptor有新的實現DynamicHttpControllerDescriptor,DyanamicHttpActionDescriptor。
Action的執行
Action方法的執行最終實現在HttpActionDescriptor的ExecuteAsync方法中。DyanamicHttpActionDescriptor也重寫了ExecuteAsync,並且將Action的返回值類型定義為AjaxResponse。

public override Type ReturnType { get { return typeof(AjaxResponse); } } public override System.Threading.Tasks.Task<object> ExecuteAsync(HttpControllerContext controllerContext, System.Collections.Generic.IDictionary<string, object> arguments, System.Threading.CancellationToken cancellationToken) { return base .ExecuteAsync(controllerContext, arguments, cancellationToken) .ContinueWith(task => { try { if (task.Result == null) { return new AjaxResponse(); } if (task.Result is AjaxResponse) { return task.Result; } return new AjaxResponse(task.Result); } catch (AggregateException ex) { ex.InnerException.ReThrow(); throw; // The previous line will throw, but we need this to makes compiler happy } }); }
IHttpControllerSelector與IHttpActionSelector
在上一篇的開頭提到了動態的WebApi的核心之一就是對原有的WebApi服務進行了替換。其中就包括IHttpControllerSelector與IHttpActionSelector,這兩個接口的主要功能就是對url進行解析生成相應的HttpControllerDescriptor與HttpControllerDescriptor,並傳給WebApi系統,再由WebApi系統去執行Action。
在上一篇中說到Abp將ApiController作DynamicApiControllerInfo緩存於DynamicApiControllerManager中,在DynamicApiControllerManager中有一DynamicApiControllers的靜態IDictionary屬性。
private static readonly IDictionary<string, DynamicApiControllerInfo> DynamicApiControllers;
在Abp系統的AbpHttpControllerSelector的中,根據url的解析出相應的服務名在DynamicApiControllerManager查找出DynamicApiControllerInfo.再生成DynamicHttpControllerDescriptor返回。

public override HttpControllerDescriptor SelectController(HttpRequestMessage request) { if (request != null) { var routeData = request.GetRouteData(); if (routeData != null) { string serviceNameWithAction; if (routeData.Values.TryGetValue("serviceNameWithAction", out serviceNameWithAction) && DynamicApiServiceNameHelper.IsValidServiceNameWithAction(serviceNameWithAction)) { var serviceName = DynamicApiServiceNameHelper.GetServiceNameInServiceNameWithAction(serviceNameWithAction); var controllerInfo = DynamicApiControllerManager.FindOrNull(serviceName); if (controllerInfo != null) { var controllerDescriptor = new DynamicHttpControllerDescriptor(_configuration, controllerInfo.ServiceName, controllerInfo.Type, controllerInfo.Filters); controllerDescriptor.Properties["__AbpDynamicApiControllerInfo"] = controllerInfo; return controllerDescriptor; } } } } return base.SelectController(request); }
DynamicApiControllerInfo中有IDictionary<string, DynamicApiActionInfo> Actions字典所以獲取Action也就十分方便。
Abp的路由
Abp定義了自己的路由格式

public static class DynamicApiRouteConfig { /// <summary> /// Registers dynamic api controllers /// </summary> public static void Register() { //Dynamic Web APIs (with area name) GlobalConfiguration.Configuration.Routes.MapHttpRoute( name: "AbpDynamicWebApi", routeTemplate: "api/services/{*serviceNameWithAction}" ); } }
具體的解析就是:
Api/services/{ServicePrefix}/{ServiceName}/{Action}
在SimpleTaskSystem中一訪問所有Tasks的url為
http://localhost:6247/api/services/tasksystem/task/GetTasks
ServicePrefix:服務前綴,由開發者自己定義
如SimpleTaskSystem:
[DependsOn(typeof(AbpWebApiModule))] //We declare depended modules explicitly public class SimpleTaskSystemWebApiModule : AbpModule { public override void Initialize() { //This code is used to register classes to dependency injection system for this assembly using conventions. IocManager.RegisterAssemblyByConvention(Assembly.GetExecutingAssembly()); //Creating dynamic Web Api Controllers for application services. //Thus, 'web api layer' is created automatically by ABP. DynamicApiControllerBuilder .ForAll<IApplicationService>(Assembly.GetAssembly(typeof (SimpleTaskSystemApplicationModule)), "tasksystem") .Build(); } }
ServiceName:服務名,由服務接口名解析而成。具體規則在BatchApiControllerBuilder. GetConventionalServiceName中

public static string GetConventionalServiceName(Type type) { var typeName = type.Name; if (typeName.EndsWith("ApplicationService")) { typeName = typeName.Substring(0, typeName.Length - "ApplicationService".Length); } else if (typeName.EndsWith("AppService")) { typeName = typeName.Substring(0, typeName.Length - "AppService".Length); } else if (typeName.EndsWith("Service")) { typeName = typeName.Substring(0, typeName.Length - "Service".Length); } if (typeName.Length > 1 && typeName.StartsWith("I") && char.IsUpper(typeName, 1)) { typeName = typeName.Substring(1); } return typeName.ToCamelCase(); }
Action:即為方法名
HttpVerb
Apb定義的四種Http訪問方式

[Flags] public enum HttpVerb { /// <summary> /// GET /// </summary> Get, /// <summary> /// POST /// </summary> Post, /// <summary> /// PUT /// </summary> Put, /// <summary> /// DELETE /// </summary> Delete, }
原本作者是定義了HttpVerb的處理方式,即對是通過方法名進行的分析。

/// <summary> /// NOTE: This is not used (as all members are private) /// </summary> internal static class DynamicApiVerbHelper { private static HttpVerb GetConventionalVerbForMethodName(string methodName) { if (methodName.StartsWith("Get")) { return HttpVerb.Get; } if (methodName.StartsWith("Update") || methodName.StartsWith("Put")) { return HttpVerb.Put; } if (methodName.StartsWith("Delete") || methodName.StartsWith("Remove")) { return HttpVerb.Delete; } if (methodName.StartsWith("Create") || methodName.StartsWith("Post")) { return HttpVerb.Post; } return GetDefaultHttpVerb(); } private static HttpVerb GetDefaultHttpVerb() { return HttpVerb.Post; } }
但作者好像並不打算這么做,在源代碼中我也沒有找到別的處理方式。