HttpControllerDescriptor与HttpActionDescriptor
HttpControllerDescriptor封装了某个HttpController类型的元数据，我们可以将它视为某个HttpController类型的描述对象。HttpActionDescriptor也类似。上一篇中说到Abp将ApiControler与Action信息分别封装于DynamicApiControllerInfo，DynamicApiActionInfo。Abp种HttpControllerDescriptor与HttpActionDescriptor有新的实现DynamicHttpControllerDescriptor，DyanamicHttpActionDescriptor。
Action的执行
Action方法的执行最终实现在HttpActionDescriptor的ExecuteAsync方法中。DyanamicHttpActionDescriptor也重写了ExecuteAsync，并且将Action的返回值类型定义为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与IHttpActionSelector
在上一篇的开头提到了动态的WebApi的核心之一就是对原有的WebApi服务进行了替换。其中就包括IHttpControllerSelector与IHttpActionSelector，这两个接口的主要功能就是对url进行解析生成相应的HttpControllerDescriptor与HttpControllerDescriptor，并传给WebApi系统，再由WebApi系统去执行Action。
在上一篇中说到Abp将ApiController作DynamicApiControllerInfo缓存于DynamicApiControllerManager中，在DynamicApiControllerManager中有一DynamicApiControllers的静态IDictionary属性。
private static readonly IDictionary<string, DynamicApiControllerInfo> DynamicApiControllers;
在Abp系统的AbpHttpControllerSelector的中，根据url的解析出相应的服务名在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字典所以获取Action也就十分方便。
Abp的路由
Abp定义了自己的路由格式
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}"
);
}
}
具体的解析就是：
Api/services/{ServicePrefix}/{ServiceName}/{Action}
在SimpleTaskSystem中一访问所有Tasks的url为
http://localhost:6247/api/services/tasksystem/task/GetTasks
ServicePrefix：服务前缀，由开发者自己定义
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:服务名，由服务接口名解析而成。具体规则在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:即为方法名
HttpVerb
Apb定义的四种Http访问方式
[Flags]
public enum HttpVerb
{
/// <summary>
/// GET
/// </summary>
Get,
/// <summary>
/// POST
/// </summary>
Post,
/// <summary>
/// PUT
/// </summary>
Put,
/// <summary>
/// DELETE
/// </summary>
Delete,
}
原本作者是定义了HttpVerb的处理方式，即对是通过方法名进行的分析。
/// <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;
}
}
但作者好像并不打算这么做，在源代码中我也没有找到别的处理方式。