GetHttpWebResponseStreamWithRetries
(
String url,
HttpStatusCode [] httpStatusCodesToFailImmediately,
RequestStatistics requestStatistics,
String userAgent,
Int32 timeoutMs,
ReportProgressHandler reportProgressHandler,
CheckCancellationPendingHandler checkCancellationPendingHandler
)
{
Debug.Assert(!String.IsNullOrEmpty(url));
Debug.Assert(requestStatistics != null);
Debug.Assert(!String.IsNullOrEmpty(userAgent));
Debug.Assert(timeoutMs > 0);
Int32 iMaximumRetries = HttpRetryDelaysSec.Length;
Int32 iRetriesSoFar = 0;
while (true)
{
if (reportProgressHandler != null && iRetriesSoFar > 0)
{
reportProgressHandler("Retrying request.");
}
// Important Note: You cannot use the same HttpWebRequest object
// for the retries. The object must be recreated each time.
HttpWebRequest oHttpWebRequest = CreateHttpWebRequest(
url, userAgent, timeoutMs);
Stream oStream = null;
try
{
if (checkCancellationPendingHandler != null)
{
checkCancellationPendingHandler();
}
oStream = GetHttpWebResponseStreamNoRetries(oHttpWebRequest);
if (reportProgressHandler != null && iRetriesSoFar > 0)
{
reportProgressHandler("Retry succeeded, continuing...");
}
requestStatistics.OnSuccessfulRequest();
return(oStream);
}
catch (Exception oException)
{
#if WriteRequestsToDebug
Debug.WriteLine("Exception: " + oException.Message);
#endif
if (oStream != null)
{
oStream.Close();
}
// The IOException "Unable to read data from the transport"
// connection: The connection was closed." can occur when
// requesting data from Twitter, for example.
if (!(
oException is WebException
||
oException is IOException
))
{
throw oException;
}
if (iRetriesSoFar == iMaximumRetries)
{
requestStatistics.OnUnexpectedException(oException);
throw (oException);
}
// If the status code is one of the ones specified in
// httpStatusCodesToFailImmediately, rethrow the exception
// without retrying the request.
if (httpStatusCodesToFailImmediately != null &&
oException is WebException)
{
if (WebExceptionHasHttpStatusCode(
(WebException)oException,
httpStatusCodesToFailImmediately))
{
throw (oException);
}
}
Int32 iSeconds = HttpRetryDelaysSec[iRetriesSoFar];
if (reportProgressHandler != null)
{
reportProgressHandler(String.Format(
"Request failed, pausing {0} {1} before retrying..."
,
iSeconds,
StringUtil.MakePlural("second", iSeconds)
));
}
System.Threading.Thread.Sleep(1000 * iSeconds);
iRetriesSoFar++;
}
}
}
GetHttpWebResponseStreamWithRetries
(
String url,
HttpStatusCode [] httpStatusCodesToFailImmediately,
RequestStatistics requestStatistics,
String userAgent,
Int32 timeoutMs,
ReportProgressHandler reportProgressHandler,
CheckCancellationPendingHandler checkCancellationPendingHandler
)
{
Debug.Assert( !String.IsNullOrEmpty(url) );
Debug.Assert(requestStatistics != null);
Debug.Assert( !String.IsNullOrEmpty(userAgent) );
Debug.Assert(timeoutMs > 0);
Int32 iMaximumRetries = HttpRetryDelaysSec.Length;
Int32 iRetriesSoFar = 0;
while (true)
{
if (reportProgressHandler != null && iRetriesSoFar > 0)
{
reportProgressHandler("Retrying request.");
}
// Important Note: You cannot use the same HttpWebRequest object
// for the retries. The object must be recreated each time.
HttpWebRequest oHttpWebRequest = CreateHttpWebRequest(
url, userAgent, timeoutMs);
Stream oStream = null;
try
{
if (checkCancellationPendingHandler != null)
{
checkCancellationPendingHandler();
}
oStream = GetHttpWebResponseStreamNoRetries(oHttpWebRequest);
if (reportProgressHandler != null && iRetriesSoFar > 0)
{
reportProgressHandler("Retry succeeded, continuing...");
}
requestStatistics.OnSuccessfulRequest();
return (oStream);
}
catch (Exception oException)
{
#if WriteRequestsToDebug
Debug.WriteLine("Exception: " + oException.Message);
#endif
if (oStream != null)
{
oStream.Close();
}
// The IOException "Unable to read data from the transport"
// connection: The connection was closed." can occur when
// requesting data from Twitter, for example.
if ( !(
oException is WebException
||
oException is IOException
) )
{
throw oException;
}
if (iRetriesSoFar == iMaximumRetries)
{
requestStatistics.OnUnexpectedException(oException);
throw (oException);
}
// If the status code is one of the ones specified in
// httpStatusCodesToFailImmediately, rethrow the exception
// without retrying the request.
if (httpStatusCodesToFailImmediately != null &&
oException is WebException)
{
if ( WebExceptionHasHttpStatusCode(
(WebException)oException,
httpStatusCodesToFailImmediately) )
{
throw (oException);
}
}
Int32 iSeconds = HttpRetryDelaysSec[iRetriesSoFar];
if (reportProgressHandler != null)
{
reportProgressHandler( String.Format(
"Request failed, pausing {0} {1} before retrying..."
,
iSeconds,
StringUtil.MakePlural("second", iSeconds)
) );
}
System.Threading.Thread.Sleep(1000 * iSeconds);
iRetriesSoFar++;
}
}
}