protected virtual Task <T> AttemptOperationAndOnFailureCallExecuteWithReplication <T>(string url, ExecuteWithReplicationState <T> state, bool avoidThrowing)
{
Task <Task <T> > finalTask = state.Operation(url).ContinueWith(task =>
{
switch (task.Status)
{
case TaskStatus.RanToCompletion:
ResetFailureCount(url);
var tcs = new TaskCompletionSource <T>();
tcs.SetResult(task.Result);
return(tcs.Task);
case TaskStatus.Canceled:
tcs = new TaskCompletionSource <T>();
tcs.SetCanceled();
return(tcs.Task);
case TaskStatus.Faulted:
Debug.Assert(task.Exception != null);
if (IsServerDown(task.Exception) && avoidThrowing)
{
return(ExecuteWithReplicationAsync(state));
}
tcs = new TaskCompletionSource <T>();
tcs.SetException(task.Exception);
return(tcs.Task);
default:
throw new InvalidOperationException("Unknown task status in AttemptOperationAndOnFailureCallExecuteWithReplication");
}
});
return(finalTask.Unwrap());
}
protected virtual Task <T> AttemptOperationAndOnFailureCallExecuteWithReplication <T>(OperationMetadata operationMetadata, OperationMetadata primaryOperationMetadata, ExecuteWithReplicationState <T> state, bool avoidThrowing)
{
var tryWithPrimaryCredentials = IsFirstFailure(operationMetadata.Url) && primaryOperationMetadata != null;
Task <Task <T> > finalTask = state.Operation(tryWithPrimaryCredentials ? new OperationMetadata(operationMetadata.Url, primaryOperationMetadata.Credentials) : operationMetadata).ContinueWith(task =>
{
switch (task.Status)
{
case TaskStatus.RanToCompletion:
ResetFailureCount(operationMetadata.Url);
var tcs = new TaskCompletionSource <T>();
tcs.SetResult(task.Result);
return(tcs.Task);
case TaskStatus.Canceled:
tcs = new TaskCompletionSource <T>();
tcs.SetCanceled();
return(tcs.Task);
case TaskStatus.Faulted:
Debug.Assert(task.Exception != null);
if (task.Exception != null)
{
var aggregateException = task.Exception;
var webException = aggregateException.ExtractSingleInnerException() as WebException;
if (tryWithPrimaryCredentials && operationMetadata.Credentials.HasCredentials() && webException != null)
{
IncrementFailureCount(operationMetadata.Url);
var response = webException.Response as HttpWebResponse;
if (response != null && response.StatusCode == HttpStatusCode.Unauthorized)
{
return(AttemptOperationAndOnFailureCallExecuteWithReplication(operationMetadata, primaryOperationMetadata, state, avoidThrowing));
}
}
}
bool timeoutThrown;
if (IsServerDown(task.Exception, out timeoutThrown) && avoidThrowing)
{
state.TimeoutThrown = timeoutThrown;
return(ExecuteWithReplicationAsync(state));
}
tcs = new TaskCompletionSource <T>();
tcs.SetException(task.Exception);
return(tcs.Task);
default:
throw new InvalidOperationException("Unknown task status in AttemptOperationAndOnFailureCallExecuteWithReplication");
}
});
return(finalTask.Unwrap());
}