private HttpActionStatus HandleWebException(Request request, HttpWebRequestState state, WebException error)
{
switch (error.Status)
{
case WebExceptionStatus.ConnectFailure:
case WebExceptionStatus.KeepAliveFailure:
case WebExceptionStatus.ConnectionClosed:
case WebExceptionStatus.PipelineFailure:
case WebExceptionStatus.NameResolutionFailure:
case WebExceptionStatus.ProxyNameResolutionFailure:
case WebExceptionStatus.SecureChannelFailure:
LogConnectionFailure(request, error, state.ConnectionAttempt);
return(HttpActionStatus.ConnectionFailure);
case WebExceptionStatus.SendFailure:
LogWebException(error);
return(HttpActionStatus.SendFailure);
case WebExceptionStatus.ReceiveFailure:
LogWebException(error);
return(HttpActionStatus.ReceiveFailure);
case WebExceptionStatus.RequestCanceled: return(HttpActionStatus.RequestCanceled);
case WebExceptionStatus.Timeout: return(HttpActionStatus.Timeout);
case WebExceptionStatus.ProtocolError: return(HttpActionStatus.ProtocolError);
default:
LogWebException(error);
return(HttpActionStatus.UnknownFailure);
}
}
private async Task <HttpActionStatus> SendRequestBodyAsync(Request request, HttpWebRequestState state)
{
try
{
state.RequestStream = await state.Request.GetRequestStreamAsync().ConfigureAwait(false);
}
catch (WebException error)
{
return(HandleWebException(request, state, error));
}
catch (Exception error)
{
LogUnknownException(error);
return(HttpActionStatus.UnknownFailure);
}
try
{
await state.RequestStream.WriteAsync(request.Content.Buffer, request.Content.Offset, request.Content.Length);
state.CloseRequestStream();
}
catch (Exception error)
{
if (IsCancellationException(error))
{
return(HttpActionStatus.RequestCanceled);
}
LogSendBodyFailure(request, error);
return(HttpActionStatus.SendFailure);
}
return(HttpActionStatus.Success);
}
private async Task <HttpActionStatus> GetResponseAsync(Request request, HttpWebRequestState state)
{
try
{
state.Response = (HttpWebResponse)await state.Request.GetResponseAsync().ConfigureAwait(false);
state.ResponseStream = state.Response.GetResponseStream();
return(HttpActionStatus.Success);
}
catch (WebException error)
{
var status = HandleWebException(request, state, error);
// (iloktionov): HttpWebRequest реагирует на коды ответа вроде 404 или 500 исключением со статусом ProtocolError.
if (status == HttpActionStatus.ProtocolError)
{
state.Response = (HttpWebResponse)error.Response;
state.ResponseStream = state.Response.GetResponseStream();
return(HttpActionStatus.Success);
}
return(status);
}
catch (Exception error)
{
LogUnknownException(error);
return(HttpActionStatus.UnknownFailure);
}
}
private static bool NeedToReadResponseBody(Request request, HttpWebRequestState state)
{
if (request.Method == RequestMethods.Head)
{
return(false);
}
// (iloktionov): ContentLength может быть равен -1, если сервер не укажет заголовок, но вернет контент. Это умолчание на уровне HttpWebRequest.
return(state.Response.ContentLength != 0);
}
private static Content CreateResponseContent(HttpWebRequestState state)
{
if (state.BodyBuffer != null)
{
return(new Content(state.BodyBuffer));
}
if (state.BodyStream != null)
{
return(new Content(state.BodyStream.GetBuffer(), 0, (int)state.BodyStream.Position));
}
return(null);
}
private static Headers CreateResponseHeaders(HttpWebRequestState state)
{
var headers = Headers.Empty;
if (state.Response == null)
{
return(headers);
}
foreach (var key in state.Response.Headers.AllKeys)
{
headers = headers.Set(key, state.Response.Headers[key]);
}
return(headers);
}
public static Response BuildFailureResponse(HttpActionStatus status, HttpWebRequestState state)
{
switch (status)
{
case HttpActionStatus.SendFailure:
return(BuildResponse(ResponseCode.SendFailure, state));
case HttpActionStatus.ReceiveFailure:
return(BuildResponse(ResponseCode.ReceiveFailure, state));
case HttpActionStatus.Timeout:
return(BuildResponse(ResponseCode.RequestTimeout, state));
case HttpActionStatus.RequestCanceled:
return(BuildResponse(ResponseCode.Canceled, state));
default:
return(BuildResponse(ResponseCode.UnknownFailure, state));
}
}
public async Task <Response> SendAsync(Request request, TimeSpan timeout, CancellationToken cancellationToken)
{
if (timeout.TotalMilliseconds < 1)
{
LogRequestTimeout(request, timeout);
return(new Response(ResponseCode.RequestTimeout));
}
var state = new HttpWebRequestState(timeout);
using (var timeoutCancellation = new CancellationTokenSource())
{
var timeoutTask = Task.Delay(state.TimeRemaining, timeoutCancellation.Token);
var senderTask = SendInternalAsync(request, state, cancellationToken);
var completedTask = await Task.WhenAny(timeoutTask, senderTask).ConfigureAwait(false);
if (completedTask is Task <Response> taskWithResponse)
{
timeoutCancellation.Cancel();
return(taskWithResponse.GetAwaiter().GetResult());
}
// (iloktionov): Если выполнившееся задание не кастуется к Task<Response>, сработал таймаут.
state.CancelRequest();
LogRequestTimeout(request, timeout);
threadPoolMonitor.ReportAndFixIfNeeded(log);
// (iloktionov): Попытаемся дождаться завершения задания по отправке запроса перед тем, как возвращать результат:
await Task.WhenAny(senderTask.ContinueWith(_ => { }), Task.Delay(requestAbortTimeout)).ConfigureAwait(false);
if (!senderTask.IsCompleted)
{
LogFailedToWaitForRequestAbort();
}
return(ResponseFactory.BuildResponse(ResponseCode.RequestTimeout, state));
}
}
private async Task <HttpActionStatus> LimitConnectTimeInternal(Task <HttpActionStatus> mainTask, Request request, HttpWebRequestState state, TimeSpan?connectTimeout)
{
using (var timeoutCancellation = new CancellationTokenSource())
{
var completedTask = await Task.WhenAny(mainTask, Task.Delay(connectTimeout.Value, timeoutCancellation.Token)).ConfigureAwait(false);
if (completedTask is Task <HttpActionStatus> taskWithResult)
{
timeoutCancellation.Cancel();
return(taskWithResult.GetAwaiter().GetResult());
}
if (!ConnectTimeoutHelper.IsSocketConnected(state.Request, log))
{
state.CancelRequestAttempt();
LogConnectionFailure(request, new WebException($"Connection attempt timed out. Timeout = {connectTimeout.Value}.", WebExceptionStatus.ConnectFailure), state.ConnectionAttempt);
return(HttpActionStatus.ConnectionFailure);
}
return(await mainTask.ConfigureAwait(false));
}
}
public Task <HttpActionStatus> LimitConnectTime(Task <HttpActionStatus> mainTask, Request request, HttpWebRequestState state, TimeSpan?connectTimeout)
{
if (connectTimeout == null)
{
return(mainTask);
}
if (!ConnectTimeoutHelper.CanCheckSocket)
{
return(mainTask);
}
if (state.TimeRemaining < connectTimeout.Value)
{
return(mainTask);
}
if (request.Url.IsLoopback)
{
return(mainTask);
}
if (ConnectTimeoutHelper.IsSocketConnected(state.Request, log))
{
return(mainTask);
}
return(LimitConnectTimeInternal(mainTask, request, state, connectTimeout));
}
private async Task <Response> SendInternalAsync(Request request, HttpWebRequestState state, CancellationToken cancellationToken)
{
using (cancellationToken.Register(state.CancelRequest))
{
for (state.ConnectionAttempt = 1; state.ConnectionAttempt <= ConnectionAttempts; state.ConnectionAttempt++)
{
using (state)
{
if (state.RequestCancelled)
{
return(new Response(ResponseCode.Canceled));
}
state.Reset();
state.Request = HttpWebRequestFactory.Create(request, state.TimeRemaining);
HttpActionStatus status;
// (iloktionov): Шаг 1 - отправить тело запроса, если оно имеется.
if (state.RequestCancelled)
{
return(new Response(ResponseCode.Canceled));
}
if (request.Content != null)
{
status = await connectTimeLimiter.LimitConnectTime(SendRequestBodyAsync(request, state), request, state, ConnectionTimeout).ConfigureAwait(false);
if (status == HttpActionStatus.ConnectionFailure)
{
continue;
}
if (status != HttpActionStatus.Success)
{
return(ResponseFactory.BuildFailureResponse(status, state));
}
}
// (iloktionov): Шаг 2 - получить ответ от сервера.
if (state.RequestCancelled)
{
return(new Response(ResponseCode.Canceled));
}
status = request.Content != null
? await GetResponseAsync(request, state).ConfigureAwait(false)
: await connectTimeLimiter.LimitConnectTime(GetResponseAsync(request, state), request, state, ConnectionTimeout).ConfigureAwait(false);
if (status == HttpActionStatus.ConnectionFailure)
{
continue;
}
if (status != HttpActionStatus.Success)
{
return(ResponseFactory.BuildFailureResponse(status, state));
}
// (iloktionov): Шаг 3 - скачать тело ответа, если оно имеется.
if (!NeedToReadResponseBody(request, state))
{
return(ResponseFactory.BuildSuccessResponse(state));
}
if (state.RequestCancelled)
{
return(new Response(ResponseCode.Canceled));
}
status = await ReadResponseBodyAsync(request, state).ConfigureAwait(false);
return(status == HttpActionStatus.Success
? ResponseFactory.BuildSuccessResponse(state)
: ResponseFactory.BuildFailureResponse(status, state));
}
}
return(new Response(ResponseCode.ConnectFailure));
}
}
private async Task <HttpActionStatus> ReadResponseBodyAsync(Request request, HttpWebRequestState state)
{
try
{
var contentLength = (int)state.Response.ContentLength;
if (contentLength > 0)
{
state.BodyBuffer = new byte[contentLength];
var totalBytesRead = 0;
// (iloktionov): Если буфер размером contentLength не попадет в LOH, можно передать его напрямую для работы с сокетом.
// В противном случае лучше использовать небольшой промежуточный буфер из пула, т.к. ссылка на переданный сохранится надолго из-за Keep-Alive.
if (contentLength < lohObjectSizeThreshold)
{
while (totalBytesRead < contentLength)
{
var bytesToRead = Math.Min(contentLength - totalBytesRead, preferredReadSize);
var bytesRead = await state.ResponseStream.ReadAsync(state.BodyBuffer, totalBytesRead, bytesToRead).ConfigureAwait(false);
if (bytesRead == 0)
{
break;
}
totalBytesRead += bytesRead;
}
}
else
{
using (var bufferHandle = readBuffersPool.AcquireHandle())
{
var buffer = bufferHandle.Resource;
while (totalBytesRead < contentLength)
{
var bytesToRead = Math.Min(contentLength - totalBytesRead, buffer.Length);
var bytesRead = await state.ResponseStream.ReadAsync(buffer, 0, bytesToRead).ConfigureAwait(false);
if (bytesRead == 0)
{
break;
}
Buffer.BlockCopy(buffer, 0, state.BodyBuffer, totalBytesRead, bytesRead);
totalBytesRead += bytesRead;
}
}
}
if (totalBytesRead < contentLength)
{
throw new EndOfStreamException($"Response stream ended prematurely. Read only {totalBytesRead} byte(s), but Content-Length specified {contentLength}.");
}
}
else
{
state.BodyStream = new MemoryStream();
using (var bufferHandle = readBuffersPool.AcquireHandle())
{
var buffer = bufferHandle.Resource;
while (true)
{
var bytesRead = await state.ResponseStream.ReadAsync(buffer, 0, buffer.Length).ConfigureAwait(false);
if (bytesRead == 0)
{
break;
}
state.BodyStream.Write(buffer, 0, bytesRead);
}
}
}
return(HttpActionStatus.Success);
}
catch (Exception error)
{
if (IsCancellationException(error))
{
return(HttpActionStatus.RequestCanceled);
}
LogReceiveBodyFailure(request, error);
return(HttpActionStatus.ReceiveFailure);
}
}
public static Response BuildSuccessResponse(HttpWebRequestState state)
{
return(BuildResponse((ResponseCode)(int)state.Response.StatusCode, state));
}
public static Response BuildResponse(ResponseCode code, HttpWebRequestState state)
{
return(new Response(code, CreateResponseContent(state), CreateResponseHeaders(state)));
}
