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POSignalr Hubs & Twitter Streaming
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copied!<p>So I'm trying to use Signalr with the Twitter Streaming API, and specifically, for this I'm using the Tweetinvi C# API (<a href="http://tweetinvi.codeplex.com/" rel="nofollow">http://tweetinvi.codeplex.com/</a>).</p> <p>The purpose of the app is to stream tweets to a page in realtime filtered with certain keywords. </p> <p>The TweetInvi library works a treat, and I have a command line application successfully printing out tweets with certain keywords in.</p> <p>The basic outline of my usage is as follows:</p> <p>I have an MVC web app with a single page, with a text input and a button (for updating filters) it then calls the Hub method in the Signalr Hub, to start the stream if there isn't one already present and Stops it on a second button click.</p> <p>All this is working fine, except when it comes to the signalr part.</p> <pre><code>public class TweetHub : Hub { private IStreamManager _streamManager; public void AddTweet(String tweet, double lat, double lon) { Clients.All.addTweet(tweet, lat, lon); } public void StartStream(String[] filters) { string accessToken = ConfigurationManager.AppSettings["AccessToken"]; string accessTokenSecret = ConfigurationManager.AppSettings["AccessTokenSecret"]; string consumerKey = ConfigurationManager.AppSettings["ConsumerKey"]; string consumerSecret = ConfigurationManager.AppSettings["ConsumerSecret"]; IToken token = new Token(accessToken, accessTokenSecret, consumerKey, consumerSecret); if (_streamManager != null && _streamManager.StreamIsOpen()) { _streamManager.StopStream(); _streamManager.StartStream(token, filters, tweet => AddTweet(tweet.Text, tweet.LocationCoordinates.Lattitude, tweet.LocationCoordinates.Longitude)); } else if (_streamManager != null && !_streamManager.StreamIsOpen()) { _streamManager.StartStream(token, filters, tweet => AddTweet(tweet.Text, tweet.LocationCoordinates.Lattitude, tweet.LocationCoordinates.Longitude)); } else { _streamManager = new StreamManager(); _streamManager.StartStream(token, filters, tweet => AddTweet(tweet.Text, tweet.LocationCoordinates.Lattitude, tweet.LocationCoordinates.Longitude)); } } public void StopStream() { if (_streamManager != null && _streamManager.StreamIsOpen()) { _streamManager.StopStream(); } } } </code></pre> <p>That is the code for my Signalr Hub. As I said, using js I can trigger the start and stop stream methods fine.</p> <p>This is the code for my StreamManager class:</p> <pre><code>public class StreamManager : IStreamManager { private StreamClient _streamClient; private bool _streamOpen = false; public void StartStream(IToken token, String[] filters, Action<ITweet> action) { if (_streamClient == null) _streamClient = new StreamClient(token, filters, new FilteredStream()); _streamClient.StartStream(action); _streamOpen = true; } public void StopStream() { if (_streamClient != null) { _streamClient.StopStream(); _streamOpen = false; } } public bool StreamIsOpen() { return _streamOpen; } public void Dispose() { if (_streamOpen) { StopStream(); } _streamClient.Dispose(); _streamClient = null; } } </code></pre> <p>The code for my StreamClient class:</p> <pre><code>public class StreamClient : IStreamClient { private IFilteredStream _filteredStream; private IToken _token; private bool _streamOpen = false; public StreamClient(IToken token, String[] filters, IFilteredStream filteredStream) { _token = token; _filteredStream = filteredStream; AddFilters(filters); } private void AddFilters(String[] filters) { for (int i = 0; i < filters.Length; ++i) { _filteredStream.AddTrack(filters[i]); } } public void StartStream(Action<ITweet> action) { _filteredStream.StartStream(_token, action); _streamOpen = true; } public void StartStream(Func<ITweet, bool> predicateFunc) { _filteredStream.StartStream(_token, predicateFunc); _streamOpen = true; } public void StopStream() { _filteredStream.StopStream(); _streamOpen = false; } public void Dispose() { Dispose(true); GC.SuppressFinalize(this); } protected virtual void Dispose(bool disposing) { if (disposing) { // free managed resources if (_streamOpen) { _filteredStream.StopStream(); _filteredStream = null; _token = null; } } } </code></pre> <p>This code above, is where it makes a call to the Tweetinvi library directly.</p> <p>My problem is that when I pass the Hub method into the StreamManager's StartStream method as an Action parameter, the AddTweet method never gets hit.</p> <p>As I said, this all works fine, when using a command prompt application as a client instead, and using this code:</p> <pre><code>static void Main(string[] args) { string accessToken = ConfigurationManager.AppSettings["AccessToken"]; string accessTokenSecret = ConfigurationManager.AppSettings["AccessTokenSecret"]; string consumerKey = ConfigurationManager.AppSettings["ConsumerKey"]; string consumerSecret = ConfigurationManager.AppSettings["ConsumerSecret"]; IToken token = new Token(accessToken, accessTokenSecret, consumerKey, consumerSecret); String[] filters = new string[2] { "test", "twitter" }; StreamClient streamClient = new StreamClient(token, filters, new FilteredStream()); streamClient.StartStream(tweet => TestMethod()); } public static void TestMethod() { Console.WriteLine("test"); } </code></pre> <p>This works perfectly and prints out tweets with those keywords as they are received.</p> <p>This leads me to believe that is a problem with the way I am using Signalr, that the signalr method is never getting hit, because the stream definitely gets opened, I just have a sneaky suspicion that it is something to do with the lifetime of the hub and the way I am using it.</p> <p>I suspect this because, although the StartStream Method in my Hub gets called fine, and updates the button being clicked, when I think click again to call StopStream, the StopStream method gets hit, but my "_streamManager" member variable is null, which it shouldn't be IF the hub maintains state during it's lifetime, which I guess it doesn't.</p> <p>Either that or it's being disposed of and then the stream wouldnt exist anymore anyway.</p> <p>I don't really have enough experience with Signalr to properly debug.</p> <p>Thanks in advance for any help. </p>

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