LinqtoTwitter TweetAsync never returns in ServiceStack App

Question

When using LinqToTwitter the status update gets posted to twitter with no problems, however the route times out and when debugging the if statement after the await line the debugger never reaches that point. What can I do to fix this?

async public Task<object> Post(RetweetPost retweetInfo){

...


var auth = new SingleUserAuthorizer
{
  CredentialStore = new SingleUserInMemoryCredentialStore
  {
    ConsumerKey = "ConsumerKey",
    ConsumerSecret = "ConsumerSecret",
    AccessToken = account.OAuthToken,
    AccessTokenSecret = account.OAuthTokenSecret
  }
};

var twitterCtx = new TwitterContext(auth);

var tweet = await twitterCtx.TweetAsync(retweetInfo.tweet);

//DOES NOT REACH THIS LINE
if (tweet != null)
{
    return new RetweetPostResponse
    {
        twitterTweetId = tweet.StatusID.ToString()
    };
}

Answer 1

I believe the real problem I was facing was the ServiceStack Framework. As discussed here. Apparently async functions on routes were not supported until ServiceStack 4.

Answer 2

You probably have a call to Task<T>.Result or Task.Wait further up your call stack. This will cause a deadlock that I describe in detail on my blog.

await will capture a "context" by default (e.g., a UI context) and use that to resume the async method. When the TweetAsync task completes, it attempts to resume within that context (e.g., on the UI thread), but it can't because there's already a thread blocked in that context (i.e., calling Result/Wait).

The best solution is to replace all Result and Wait calls with await.