CODEWITHSUNDEEP
c#asynchronous
Andrew
Andrew

Reputation: 701

async Exception not being caught

I have a windows service that references the following code. My code that uses the below method contains a try..catch block but it doesn't seem to catch RefereshTokenException that is thrown in the below method. Obviously my understanding of async is not correct. 

private async void RefreshTokens()
{
    try
    {
        var cognito = new CognitoApi();
        var response = cognito.TokenRefresh(_refreshToken);

        if (response.HttpStatusCode == HttpStatusCode.OK)
        {
            _idToken = new AwsToken(response.AuthenticationResult.IdToken);
            _accessToken = new AwsToken(response.AuthenticationResult.AccessToken);
        }
        else
        {
            await _signIn(_credentials.SiteId, _credentials.LocationId, null);
        }
    }
    catch (NotAuthorizedException)
    {
        await _signIn(_credentials.SiteId, _credentials.LocationId, null);
    }
    catch (Exception ex)
    {
        throw new RefreshTokenException("Failed refreshing tokens.", ex);
    }
}

This is the code that calls RefreshTokens

public async void Process(QueueMessage queueMessage, Action<QueueMessage> retryAction)
{
    _processingCounter.Increment();

    try
    {
        ......
        IAwsToken idToken = authenticationService.Tokens.IdToken; //This is the code that calls "RefreshTokens" method
        ........
    }
    catch (Exception ex)
    {
        //Code never reaches here...
        _logger.Error("Error in ProcessMessage", ex);
    }

    _processingCounter.Decrement();
}

Upvotes: 0

Views: 108

Answers (1)

bommelding
bommelding

Reputation: 3037

This is an async void. One of the main reasons to avoid async void methods is that you cannot handle the exceptions they throw.

Make it an async Task and await it in the caller.

Note that you then have the same issue in that caller, async void Process(...)

Make that an async Task as well and work your way up. async/await should form a chain, from your GUI or Controller down to an async I/O call.

Upvotes: 5

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