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fix error mapping in HttpWebRequest to handle NetworkException #40666

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Merged
geoffkizer merged 2 commits into from
Aug 12, 2020
+14 −5
Merged

fix error mapping in HttpWebRequest to handle NetworkException #40666

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be43782
fix error mapping in HttpWebRequest to handle NetworkException
Aug 11, 2020
75d7f77
add mapping for SocketError.NoData => NetworkError.HostNotFound
Aug 11, 2020
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1 change: 1 addition & 0 deletions src/libraries/Common/src/System/Net/NetworkErrorHelper.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,7 @@ internal static NetworkException MapSocketException(SocketException socketExcept
{
SocketError.AddressAlreadyInUse => NetworkError.EndPointInUse,
SocketError.HostNotFound => NetworkError.HostNotFound,
SocketError.NoData => NetworkError.HostNotFound,
SocketError.ConnectionRefused => NetworkError.ConnectionRefused,
SocketError.OperationAborted => NetworkError.OperationAborted,
SocketError.ConnectionAborted => NetworkError.ConnectionAborted,
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9 changes: 9 additions & 0 deletions src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/ConnectHelper.cs
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Expand Up @@ -61,6 +61,15 @@ public static Connection Connect(string host, int port, CancellationToken cancel
socket.Connect(new DnsEndPoint(host, port));
}
}
catch (SocketException se)
{
socket.Dispose();

// SocketConnectionFactory wraps SocketException in NetworkException. Do the same here.
NetworkException ne = NetworkErrorHelper.MapSocketException(se);

throw CreateWrappedException(ne, host, port, cancellationToken);
}
Comment on lines +64 to +72

@antonfirsov antonfirsov Aug 11, 2020

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Wouldn't it be wise to add a test for this path?

@geoffkizer geoffkizer Aug 12, 2020

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Probably, yeah. I want to get this in so people aren't seeing this in CI.

catch (Exception e)
{
socket.Dispose();
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9 changes: 4 additions & 5 deletions src/libraries/System.Net.Requests/src/System/Net/WebException.cs
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Expand Up @@ -96,18 +96,17 @@ internal static Exception CreateCompatibleException(Exception exception)

private static WebExceptionStatus GetStatusFromExceptionHelper(HttpRequestException ex)
{
SocketException? socketEx = ex.InnerException as SocketException;
NetworkException? networkException = ex.InnerException as NetworkException;

@stephentoub stephentoub Aug 12, 2020 •
edited
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Any concerns about a breaking change here for other consumers of HttpClient? i.e. if WebRequest is fishing out the inner exception and expecting it to be a SocketException and now it's a NetworkException?

@geoffkizer geoffkizer Aug 12, 2020

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It's a minor concern, but I'm not sure there's a better option.

Note that this only matters for exceptions that come during Connect, since those are the only ones that have SocketException as the inner exception today. Other exceptions are already IOExceptions.

The ConnectionFactory stuff is generalizing the Connect path so that you can plug in your own transport. In general these can't throw SocketException, and that's what we invented NetworkException for. We could special case SocketConnectionFactory in SocketsHttpHandler, pull out the inner SocketException, and discard the NetworkException, but that means we'll have different exception behavior based on whether you use SocketConnectionFactory or not, which seems bad.

Long-term, a better solution here would be to have distinct HttpRequestException errors like HostNotFound so that a user can inspect it directly and doesn't need to fish out the inner exception. WebRequestException already has this, as you can see here. We've discussed doing this in the past but haven't actually implemented it.


if (socketEx is null)
if (networkException is null)
{
return WebExceptionStatus.UnknownError;
}

WebExceptionStatus status;
switch (socketEx.SocketErrorCode)
switch (networkException.NetworkError)
{
case SocketError.NoData:
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case SocketError.HostNotFound:
case NetworkError.HostNotFound:
status = WebExceptionStatus.NameResolutionFailure;
break;
default:
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