/// <summary>
/// Invokes service method that returns a value of type T.
/// </summary>
protected T Invoke <T>(ServiceMethod <T> method)
{
const int maxRetryCount = 1;
int retryCount = 0;
while (true)
{
var client = _AcquireClient();
try
{
return(method.Invoke(client));
}
catch (Exception e)
{
if (ProxyAuthenticationErrorHandler.HandleError(e))
{
continue;
}
var isTokenError = _IsTokenError(e);
if (retryCount >= maxRetryCount || !isTokenError)
{
if (ServiceHelper.IsCommunicationError(e))
{
throw ServiceHelper.CreateCommException(
_connection.Title,
e);
}
throw;
}
if (isTokenError)
{
_connection.GenerateToken();
_CloseClient(client);
client = null;
}
++retryCount;
}
finally
{
_ReleaseClient(client);
}
}
}
/// <summary>
/// Attempts to prepare for retrying request sending upon catching the
/// specified exception.
/// </summary>
/// <param name="exception">The exception caused failure of the previous
/// request sending.</param>
/// <returns>True if and only if the request sending could be repeated.</returns>
private bool _PrepareRetry(Exception exception)
{
var restException = exception as RestException;
if (restException != null)
{
return(false);
}
if (ProxyAuthenticationErrorHandler.HandleError(exception))
{
return(true);
}
if (_IsTransientError(exception))
{
Thread.Sleep(RETRY_WAIT_TIME);
return(true);
}
return(false);
}
/// <summary>
/// Handles AsyncCompleted event results.
/// </summary>
/// <returns>
/// Returns true if the operation is completed, false if it's retried.
/// </returns>
protected bool IsAsyncCompleted(object sender, AsyncCompletedEventArgs args,
out AsyncCompletedEventArgs outArgs)
{
outArgs = null;
Guid id = Guid.Empty;
Exception error = args.Error;
object userState = null;
bool isCompleted = true;
try
{
TClient client = (TClient)sender;
_DecrementAsyncRefCount(client);
if (args.UserState == null)
{
throw new InvalidOperationException();
}
id = (Guid)args.UserState;
AsyncContext ctx = null;
if (!_asyncContextMap.TryGetValue(id, out ctx))
{
throw new InvalidOperationException();
}
userState = ctx.UserState;
if (_IsAsyncFailed(args))
{
bool needToRetry =
ctx.RetryCount == 0 &&
_IsTokenError(args.Error);
if (ProxyAuthenticationErrorHandler.HandleError(args.Error))
{
needToRetry = true;
}
if (needToRetry)
{
_connection.GenerateToken(); // update token
}
if (needToRetry || client.State == CommunicationState.Faulted)
{
_CloseClient(client);
// do retry if needed
if (needToRetry)
{
client = _AcquireClient();
_IncrementAsyncRefCount(client);
ctx.RetryMethod(client);
isCompleted = false;
}
}
}
}
catch (Exception e)
{
error = e;
}
if (isCompleted)
{
if (error != null)
{
error = _ConvertCommException(error);
}
_asyncContextMap.Remove(id);
outArgs = new AsyncCompletedEventArgs(error, args.Cancelled, userState);
}
return(isCompleted);
}