Throw TimeoutException upon HTTP timeout.

The HttpClient.SendAsync method throws an OperationCanceledException
when the timeout is exceeded.  In order to provide a more informative
exception, we will detect this case and throw a TimeoutException
instead.  This will also allow the BackendUploader to differentiate
between cancellations requested by the user and those generated by
an HTTP timeout.

Previously, a ThreadAbortException or OperationCanceledException would
be rethrown in the BackendUploader.DoWithRetry method.  However, the
modifications made in revision 61f511c087ae0e3fbb6295484a8bd9e36720f1b7
from pull request #3684 appear to have let this case slip through.

See the following links for more information:

https://stackoverflow.com/questions/10547895/how-can-i-tell-when-httpclient-has-timed-out
https://thomaslevesque.com/2018/02/25/better-timeout-handling-with-httpclient

This addresses issue #3772.

1 files changed, 13 insertions, 2 deletions

diff --git a/Duplicati/Library/Backend/OAuthHelper/OAuthHttpClient.cs b/Duplicati/Library/Backend/OAuthHelper/OAuthHttpClient.cs
index 360d5e75c..b6e48bee6 100644
--- a/Duplicati/Library/Backend/OAuthHelper/OAuthHttpClient.cs
+++ b/Duplicati/Library/Backend/OAuthHelper/OAuthHttpClient.cs
@@ -68,9 +68,20 @@ namespace Duplicati.Library
                 this.PreventAuthentication(request);

             }

 

-            return await this.SendAsync(request, token).ConfigureAwait(false);

+            // The HttpClient.SendAsync method throws an OperationCanceledException when the timeout is exceeded.

+            // In order to provide a more informative exception, we will detect this case and throw a TimeoutException

+            // instead.  This will also allow the BackendUploader to differentiate between cancellations requested by

+            // the user and those generated by timeouts.

+            try

+            {

+                return await this.SendAsync(request, token).ConfigureAwait(false);

+            }

+            catch (OperationCanceledException ex) when (!token.IsCancellationRequested)

+            {

+                throw new TimeoutException($"HTTP timeout {this.Timeout} exceeded.");

+            }

         }

-

+        

         /// <summary>

         /// Prevents authentication from being applied on the given request

         /// </summary>