private static void CompleteFailedTask(RevaleeTask task, string message)
{
Supervisor.State.CompleteTask(task);
Supervisor.LogEvent(message, TraceEventType.Error);
Supervisor.Telemetry.RecordWaitTime(CalculateWaitTime(DateTime.UtcNow, task));
Supervisor.Telemetry.RecordFailedCallback();
}
private static TimeSpan CalculateWaitTime(DateTime time, RevaleeTask task)
{
if (task.CallbackTime > task.CreatedTime)
{
if (task.CallbackTime < time)
{
return(time.Subtract(task.CallbackTime));
}
else
{
return(TimeSpan.Zero);
}
}
else
{
if (task.CreatedTime < time)
{
return(time.Subtract(task.CreatedTime));
}
else
{
return(TimeSpan.Zero);
}
}
}
private void ProcessWebException(RevaleeTask task, WebException wex)
{
HttpWebResponse failedResponse = (HttpWebResponse)wex.Response;
if (failedResponse != null)
{
switch (DetermineResult(failedResponse.StatusCode))
{
case CallbackResult.NonretryableError:
CompleteFailedTask(task, FormatHttpErrorMessage(task, failedResponse.StatusCode));
break;
default:
CompleteRetryableTask(task, FormatHttpErrorMessage(task, failedResponse.StatusCode));
break;
}
}
else
{
switch (DetermineResult(wex.Status))
{
case CallbackResult.NonretryableError:
CompleteFailedTask(task, FormatWebExceptionMessage(task, wex));
break;
default:
CompleteRetryableTask(task, FormatWebExceptionMessage(task, wex));
break;
}
}
}
private static void CompleteFailedTask(RevaleeTask task, Exception exception)
{
Supervisor.State.CompleteTask(task);
Supervisor.LogException(exception, TraceEventType.Error, task.CallbackUrl.OriginalString);
Supervisor.Telemetry.RecordWaitTime(CalculateWaitTime(DateTime.UtcNow, task));
Supervisor.Telemetry.RecordFailedCallback();
}
private static HttpWebRequest PrepareWebRequest(RevaleeTask task)
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(FormatCallbackRequestUrl(task.CallbackUrl));
request.ServicePoint.Expect100Continue = false;
request.AllowAutoRedirect = true;
request.MaximumAutomaticRedirections = 10;
request.KeepAlive = false;
request.Method = "POST";
request.Pipelined = false;
request.Timeout = 30000;
request.UserAgent = "Revalee";
request.ContentType = "application/x-www-form-urlencoded";
if (!string.IsNullOrEmpty(task.AuthorizationCipher))
{
string responseCipher = BuildResponseAuthorizationCipher(task.AuthorizationCipher, task.CallbackId);
if (responseCipher != null)
{
request.Headers.Add("Revalee-Auth", responseCipher);
}
}
string postedData = FormatFormPayload(task);
request.ContentLength = postedData.Length;
using (Stream stream = request.GetRequestStream())
{
stream.Write(Encoding.UTF8.GetBytes(postedData), 0, postedData.Length);
}
return(request);
}
private static void CompleteSuccessfulTask(RevaleeTask task)
{
Supervisor.State.CompleteTask(task);
Supervisor.LogEvent(string.Format("Successful callback to {0}. [{1}]", task.CallbackUrl.OriginalString, task.CallbackId), TraceEventType.Verbose);
Supervisor.Telemetry.RecordWaitTime(CalculateWaitTime(DateTime.UtcNow, task));
Supervisor.Telemetry.RecordSuccessfulCallback();
RetryHeuristics.OnSuccess(task.CallbackUrl);
}
private static void CompleteFailedTask(RevaleeTask task, HttpStatusCode statusCode)
{
Supervisor.State.CompleteTask(task);
Supervisor.LogEvent(string.Format("Unsuccessful callback to {0} due to HTTP status code {1}. [{2}]",
task.CallbackUrl.OriginalString, (int)statusCode, task.CallbackId), TraceEventType.Error);
Supervisor.Telemetry.RecordWaitTime(CalculateWaitTime(DateTime.UtcNow, task));
Supervisor.Telemetry.RecordFailedCallback();
}
private void ProcessTask(object state)
{
RevaleeTask task = (RevaleeTask)state;
if (!task.AttemptCallback())
{
return;
}
try
{
HttpWebRequest request = PrepareWebRequest(task);
Task <WebResponse> responseTask = Task.Factory.FromAsync <WebResponse>(request.BeginGetResponse, request.EndGetResponse, request);
responseTask.ContinueWith(t =>
{
HttpWebResponse response = null;
try
{
response = (HttpWebResponse)t.Result;
ProcessWebResponse(task, response);
}
catch (WebException wex)
{
ProcessWebException(task, wex);
}
catch (AggregateException aex)
{
WebException wex = ExtractWebException(aex);
if (wex != null)
{
ProcessWebException(task, wex);
}
else
{
// Non-retryable error
CompleteFailedTask(task, FormatGenericExceptionMessage(task, aex));
}
}
finally
{
if (response != null)
{
response.Close();
}
}
});
}
catch (WebException wex)
{
ProcessWebException(task, wex);
}
catch (SecurityException sex)
{
// Non-retryable error
CompleteFailedTask(task, FormatGenericExceptionMessage(task, sex));
}
}
public void ReenlistTask(RevaleeTask task)
{
if (task == null)
{
throw new ArgumentNullException("task");
}
_AwaitingTaskCollection.AddOrReplace(task.CallbackId, task, task.CallbackTime);
ResetTaskAlarm();
}
private static void RetryTask(RevaleeTask task)
{
// Update the persisted attempt counts
Supervisor.State.UpdateTask(task);
// Reenlist task to be retried later
TimeSpan retryDelay = RetryHeuristics.OnRetryableFailure(task.CallbackUrl);
DateTime delayedCallbackTime = DateTime.UtcNow.Add(retryDelay);
Supervisor.State.ReenlistTask(task, delayedCallbackTime);
Supervisor.LogEvent(string.Format("Retrying callback to {0} after waiting {1}. [{2}]", task.CallbackUrl.OriginalString, retryDelay, task.CallbackId), TraceEventType.Information);
}
private static void CompleteRetryableTask(RevaleeTask task, Exception exception)
{
if (task.AttemptsRemaining > 0)
{
RetryTask(task);
}
else
{
// Out of attempts
CompleteFailedTask(task, exception);
}
}
private static void CompleteRetryableTask(RevaleeTask task, HttpStatusCode statusCode)
{
if (task.AttemptsRemaining > 0)
{
RetryTask(task);
}
else
{
// Out of attempts
CompleteFailedTask(task, statusCode);
}
}
private static string FormatFormPayload(RevaleeTask task)
{
var payload = new StringBuilder();
payload.Append("CallbackId=");
payload.Append(task.CallbackId.ToString("D"));
payload.Append("&CallbackTime=");
payload.Append(task.CallbackTime.ToString(@"yyyy-MM-dd\THH:mm:ss.fff\Z", CultureInfo.InvariantCulture));
payload.Append("&CurrentServiceTime=");
payload.Append(DateTime.UtcNow.ToString(@"yyyy-MM-dd\THH:mm:ss.fff\Z", CultureInfo.InvariantCulture));
return(payload.ToString());
}
public void CompleteTask(RevaleeTask task)
{
if (task == null)
{
throw new ArgumentNullException("task");
}
lock (_SyncRoot)
{
_PersistenceProvider.RemoveTask(task);
Supervisor.Telemetry.DecrementAwaitingTasksValue();
}
}
public void UpdateTask(RevaleeTask task)
{
if (task == null)
{
throw new ArgumentNullException("task");
}
lock (_SyncRoot)
{
_PersistenceProvider.RemoveTask(task);
_PersistenceProvider.AddTask(task);
}
}
private static void CompleteRetryableTask(RevaleeTask task, string message)
{
if (task.AttemptsRemaining > 0)
{
Supervisor.LogEvent(message, TraceEventType.Warning);
RetryTask(task);
}
else
{
// Out of attempts
CompleteFailedTask(task, message);
}
}
public void ReenlistTask(RevaleeTask task, DateTime due)
{
if (task == null)
{
throw new ArgumentNullException("task");
}
if (due.Kind != DateTimeKind.Utc)
{
throw new ArgumentException("DateTime argument not provided in UTC.", "due");
}
_AwaitingTaskCollection.AddOrReplace(task.CallbackId, task, due);
ResetTaskAlarm();
}
public void AddTask(RevaleeTask task)
{
if (task == null)
{
throw new ArgumentNullException("task");
}
lock (_SyncRoot)
{
_PersistenceProvider.AddTask(task);
}
_AwaitingTaskCollection.AddOrReplace(task.CallbackId, task, task.CallbackTime);
Supervisor.Telemetry.IncrementAwaitingTasksValue();
ResetTaskAlarm();
}
private void ProcessWebResponse(RevaleeTask task, HttpWebResponse response)
{
switch (DetermineResult(response.StatusCode))
{
case CallbackResult.Success:
CompleteSuccessfulTask(task);
break;
case CallbackResult.NonretryableError:
CompleteFailedTask(task, FormatHttpErrorMessage(task, response.StatusCode));
break;
default:
CompleteRetryableTask(task, FormatHttpErrorMessage(task, response.StatusCode));
break;
}
}
public void CancelTask(RevaleeTask task)
{
if (task == null)
{
throw new ArgumentNullException("task");
}
RevaleeTask awaitingTask;
if (_AwaitingTaskCollection.TryGetValue(task.CallbackId, out awaitingTask))
{
if (awaitingTask.CallbackUrl.ToString().StartsWith(task.CallbackUrl.ToString(), StringComparison.OrdinalIgnoreCase))
{
RevaleeTask removedTask;
bool wasTaskRemoved = _AwaitingTaskCollection.TryRemove(awaitingTask.CallbackId, out removedTask);
lock (_SyncRoot)
{
_PersistenceProvider.RemoveTask(awaitingTask);
}
if (wasTaskRemoved)
{
Supervisor.Telemetry.DecrementAwaitingTasksValue();
}
}
}
else
{
RevaleeTask storedTask = RetrieveTask(task.CallbackId);
if (storedTask != null)
{
if (storedTask.CallbackUrl.ToString().StartsWith(task.CallbackUrl.ToString(), StringComparison.OrdinalIgnoreCase))
{
lock (_SyncRoot)
{
_PersistenceProvider.RemoveTask(storedTask);
}
}
}
}
}
public void AddTask(RevaleeTask Task)
{
return;
}
private static string FormatHttpErrorMessage(RevaleeTask task, HttpStatusCode statusCode)
{
return(string.Format("Unsuccessful callback to {0} due to HTTP status code {1}. [{2}]",
task.CallbackUrl.OriginalString, (int)statusCode, task.CallbackId));
}
public void RemoveTask(RevaleeTask Task)
{
return;
}
private void ProcessTask(object state)
{
RevaleeTask task = (RevaleeTask)state;
if (!task.AttemptCallback())
{
return;
}
try
{
HttpWebRequest request = PrepareWebRequest(task);
Task <WebResponse> responseTask = Task.Factory.FromAsync <WebResponse>(request.BeginGetResponse, request.EndGetResponse, request);
responseTask.ContinueWith(t =>
{
try
{
HttpWebResponse response = null;
try
{
response = (HttpWebResponse)t.Result;
ProcessWebResponse(task, response);
}
catch (AggregateException aex)
{
if (aex.InnerExceptions.Count == 1 && aex.InnerExceptions[0] is WebException)
{
ProcessWebException(task, aex.InnerExceptions[0] as WebException);
}
else
{
aex = aex.Flatten();
if (aex.InnerExceptions.Count > 0)
{
throw aex.InnerExceptions[0];
}
else
{
throw;
}
}
}
finally
{
if (response != null)
{
response.Close();
}
}
}
catch (WebException wex)
{
ProcessWebException(task, wex);
}
catch (AggregateException aex)
{
// Non-retryable error
CompleteFailedTask(task, aex);
}
});
}
catch (WebException wex)
{
ProcessWebException(task, wex);
}
catch (SecurityException sex)
{
// Non-retryable error
CompleteFailedTask(task, sex);
}
}
public void Process(HttpListenerRequest request, HttpListenerResponse response)
{
try
{
if (request.HttpMethod != "PUT" && request.HttpMethod != "DELETE")
{
FinalizeRejectedResponse(request, response, 405, "Method Not Supported", null);
return;
}
if (request.QueryString.Count < 2)
{
FinalizeRejectedResponse(request, response, 400, "Bad Request", null);
return;
}
Guid?guid = RetrieveGuidParameter(request);
if (!guid.HasValue)
{
FinalizeRejectedResponse(request, response, 400, "Bad Request", null);
return;
}
Uri url = RetrieveUrlParameter(request);
if (url == null)
{
FinalizeRejectedResponse(request, response, 400, "Bad Request", null);
return;
}
if (UrlContainsDangerousMarkup(url))
{
FinalizeRejectedResponse(request, response, 400, "Bad Request", url);
return;
}
RevaleeUrlAuthorization authorization = Supervisor.Configuration.AuthorizedTargets.Match(url);
if (authorization == null)
{
// Keep all authorization errors homogeneous from the client perspective
RevaleeUrlAuthorization.ObfuscateExecutionTime();
FinalizeRejectedResponse(request, response, 401, "Unauthorized", url);
return;
}
if (!authorization.IsAuthorizedRequestSource(request.RemoteEndPoint.Address))
{
// Keep all authorization errors homogeneous from the client perspective
RevaleeUrlAuthorization.ObfuscateExecutionTime();
FinalizeRejectedResponse(request, response, 401, "Unauthorized", url);
return;
}
if (Supervisor.Work.IsOverloaded)
{
FinalizeRejectedResponse(request, response, 503, "Service Unavailable", url);
return;
}
RevaleeTask taskToCancel = RevaleeTask.Revive(DateTime.MinValue, url, DateTime.UtcNow, guid.Value, 0, null);
Supervisor.State.CancelTask(taskToCancel);
FinalizeAcceptedResponse(request, response, guid.Value, url);
return;
}
catch (HttpListenerException hlex)
{
Supervisor.LogException(hlex, TraceEventType.Error, request.RawUrl);
FinalizeRejectedResponse(request, response, 500, "Error Occurred", null);
return;
}
}
public void Process(HttpListenerRequest request, HttpListenerResponse response)
{
try
{
if (request.HttpMethod != "PUT")
{
FinalizeRejectedResponse(request, response, 405, "Method Not Supported", null);
return;
}
if (request.QueryString.Count < 2)
{
FinalizeRejectedResponse(request, response, 400, "Bad Request", null);
return;
}
Uri url = RetrieveUrlParameter(request);
if (url == null)
{
FinalizeRejectedResponse(request, response, 400, "Bad Request", null);
return;
}
DateTime?time = RetrieveTimeParameter(request);
if (!time.HasValue)
{
FinalizeRejectedResponse(request, response, 400, "Bad Request", url);
return;
}
if (UrlContainsDangerousMarkup(url))
{
FinalizeRejectedResponse(request, response, 400, "Bad Request", url);
return;
}
RevaleeUrlAuthorization authorization = Supervisor.Configuration.AuthorizedTargets.Match(url);
if (authorization == null)
{
// Keep all authorization errors homogeneous from the client perspective
RevaleeUrlAuthorization.ObfuscateExecutionTime();
FinalizeRejectedResponse(request, response, 401, "Unauthorized", url);
return;
}
if (!authorization.IsAuthorizedRequestSource(request.RemoteEndPoint.Address))
{
// Keep all authorization errors homogeneous from the client perspective
RevaleeUrlAuthorization.ObfuscateExecutionTime();
FinalizeRejectedResponse(request, response, 401, "Unauthorized", url);
return;
}
if (Supervisor.Work.IsOverloaded)
{
FinalizeRejectedResponse(request, response, 503, "Service Unavailable", url);
return;
}
string authorizationCipher = RetrieveAuthorizationHeader(request);
RevaleeTask newTask = new RevaleeTask(time.Value, url, authorization.RetryCount, authorizationCipher);
Supervisor.State.AddTask(newTask);
FinalizeAcceptedResponse(request, response, newTask);
return;
}
catch (HttpListenerException hlex)
{
Supervisor.LogException(hlex, TraceEventType.Error, request.RawUrl);
FinalizeRejectedResponse(request, response, 500, "Error Occurred", null);
return;
}
}
private static string FormatGenericExceptionMessage(RevaleeTask task, Exception exception)
{
return(string.Format("{0} [{1}]", exception.Message, task.CallbackUrl.OriginalString));
}
private static string FormatWebExceptionMessage(RevaleeTask task, WebException webException)
{
return(string.Format("Unsuccessful callback to {0} with status '{1}'. [{2}]",
task.CallbackUrl.OriginalString, webException.Status.ToString(), task.CallbackId));
}
private static void FinalizeAcceptedResponse(HttpListenerRequest request, HttpListenerResponse response, RevaleeTask task)
{
string remoteAddress = request.RemoteEndPoint.Address.ToString();
try
{
response.StatusCode = 200;
response.StatusDescription = "OK";
byte[] confirmation_number = Encoding.UTF8.GetBytes(task.CallbackId.ToString());
response.ContentLength64 = confirmation_number.LongLength;
response.OutputStream.Write(confirmation_number, 0, confirmation_number.Length);
}
finally
{
response.Close();
}
Supervisor.Telemetry.RecordAcceptedRequest();
Supervisor.LogEvent(string.Format("Request accepted for {0} @ {1:d} {1:t} from {2}. [{3}]", task.CallbackUrl.OriginalString, task.CallbackTime, remoteAddress, task.CallbackId), TraceEventType.Verbose);
}
