我目前正在使用多个委派处理程序(派生自DelegatingHandler
的类)在发送之前处理请求,例如验证签名等。这一切都非常好,因为我没有在所有调用上复制签名验证(例如)。
我想对来自同一网络请求的响应使用相同的原则。是否有类似于DelegatingHandler的响应?一种在回复方法之前捕获响应的方法吗?
其他信息:
我使用HttpClient.PutAsync(...)
答案 0 :(得分:43)
是。您可以在继续任务中执行此操作。
我解释一下here。
例如,此代码(来自上面的博客)跟踪请求URI并向响应添加虚拟标头。
public class DummyHandler : DelegatingHandler
{
protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
{
// work on the request
Trace.WriteLine(request.RequestUri.ToString());
var response = await base.SendAsync(request, cancellationToken);
response.Headers.Add("X-Dummy-Header", Guid.NewGuid().ToString());
return response;
}
}
答案 1 :(得分:17)
以下是拦截请求和响应的示例。重写方法SendAsync用于捕获原始请求,而名为ResponseHandler的方法用于捕获响应。
捕获原始请求和响应的示例
using System.Net.Http;
using System.Threading.Tasks;
namespace webAPI_Test
{
public class MessageInterceptor : DelegatingHandler
{
protected override System.Threading.Tasks.Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, System.Threading.CancellationToken cancellationToken)
{
// CATCH THE REQUEST BEFORE SENDING TO THE ROUTING HANDLER
var headers = request.ToString();
var body = request.Content.ReadAsStringAsync().Result;
var fullRequest = headers + "\n" + body;
// SETUP A CALLBACK FOR CATCHING THE RESPONSE - AFTER ROUTING HANDLER, AND AFTER CONTROLLER ACTIVITY
return base.SendAsync(request, cancellationToken).ContinueWith(
task =>
{
// GET THE COPY OF THE TASK, AND PASS TO A CUSTOM ROUTINE
ResponseHandler(task);
// RETURN THE ORIGINAL RESULT
var response = task.Result;
return response;
}
);
}
public void ResponseHandler(Task<HttpResponseMessage> task)
{
var headers = task.Result.ToString();
var body = task.Result.Content.ReadAsStringAsync().Result;
var fullResponse = headers + "\n" + body;
}
}
}
要使用此方法,需要标识该类并将其注册为MessageHandler。我将以下行添加到我的Global.asax文件中......
示例如何注册新的MessageInterceptor类
GlobalConfiguration.Configuration.MessageHandlers.Add(new MessageInterceptor());
这是我完整的Global.asax文件。注意MessageInterceptor是如何引用的......
Global.asax的完整版本显示MessageInterceptor集成
using System.Web.Http;
using System.Web.Mvc;
using System.Web.Optimization;
using System.Web.Routing;
namespace webAPI_Test
{
// Note: For instructions on enabling IIS6 or IIS7 classic mode,
// visit http://go.microsoft.com/?LinkId=9394801
public class WebApiApplication : System.Web.HttpApplication
{
protected void Application_Start()
{
AreaRegistration.RegisterAllAreas();
WebApiConfig.Register(GlobalConfiguration.Configuration);
FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
RouteConfig.RegisterRoutes(RouteTable.Routes);
BundleConfig.RegisterBundles(BundleTable.Bundles);
GlobalConfiguration.Configuration.MessageHandlers.Add(new MessageInterceptor());
}
}
}