我试图根据新的fw 4.5功能(如HttpClient和await/async)重写旧网络身份验证逻辑,并且遇到请求和响应之间的意外延迟(大约15秒)。我的猜测是,这是因为客户端试图从IE浏览器中查找/使用代理服务器,就像使用旧的HttpRequest/WebClient一样。下面的代码:新的HttpClient代理设置问题
public static async Task<AuthResult> GetDataFromServiceAsync(string url, string login, string password)
{
Debug.WriteLine("[" + DateTime.Now + "] GetDataFromServiceAsync");
var handler = new HttpClientHandler { Credentials = new NetworkCredential(login, password)/*, UseProxy = false*/ };
var client = new HttpClient(handler) { MaxResponseContentBufferSize = Int32.MaxValue };
try
{
var resp = await client.GetAsync(new Uri(url));
var content = resp.Content.ReadAsStringAsync().Result;
var auth = ParseContent(content);
Debug.WriteLine("[" + DateTime.Now + "] Returning AuthResult : " + auth);
return new AuthResult { Success = auth, Exception = null};
}
catch (Exception exception)
{
//
Debug.WriteLine("[" + DateTime.Now + "] Returning error AuthResult : " + exception.Message);
return new AuthResult { Success = false, Exception = exception }; ;
}
}
}
这种方法是包裹着从API等方法,实际上什么也不做相关的当前情况:
public async Task<AuthResult> IsAuthenticated(string login, string password)
{
Debug.WriteLine("[" + DateTime.Now + "] Starting ISAuthenticationService.IsAuthenticated");
// ... (cut) ...
// async
var authResult = await ISHelpers.GetDataFromServiceAsync(url, login, password);
Debug.WriteLine("[" + DateTime.Now + "] Ending ISAuthenticationService.IsAuthenticated");
return authResult;
}
认证发生在相应的视图模型的命令:
private async void ExecuteAuthenticationCommand()
{
// Test stub
//var authService = new Helpers.MockupAuthenticationService();
var authService = new Helpers.ISAuthenticationService();
var auth = await authService.IsAuthenticated(Login, Password);
if (auth.Success)
{
MessageBox.Show("Authentication success");
Messenger.Default.Send<LoginDataItem>(_dataItem);
}
else
{
MessageBox.Show(auth.Exception.Message, "Incorrect login data");
}
}
调试输出:
[27.06.2012 16:54:10] Starting ISAuthenticationService.IsAuthenticated
[27.06.2012 16:54:10] GetDataFromServiceAsync
[27.06.2012 16:54:25] ParseContent in GetDataFromServiceAsync
[27.06.2012 16:54:25] Returning AuthResult : True
[27.06.2012 16:54:25] Ending ISAuthenticationService.IsAuthenticated
当我在HttpClientHandler设置中取消注释UseProxy = false时,延迟消失且auth没有延迟。即使我没有取消注释UseProxy(每运行大约十次运行一次),问题也会发生。问题是 - 是一个错误还是什么?试图从服务器端进行调试,发现轮询请求之间没有差异。提前致谢。
为什么有时候检测会立即发生?为什么HttpClient甚至与IE有关?阅读MSDN并没有找到任何的参考。 – Jaded