killnine / hubconnectionmanager

SignalR extension to help retry connecting to server if initialization fails on startup. Also provides more convenient unit testing interface.

##HubConnectionManager##

###Overview###

HubConnectionManager is a simple wrapper class around the HubConnection class SignalR uses to establish a connection with a server.

###NuGet Installation### > Install-Package HubConnectionManager

https://www.nuget.org/packages/HubConnectionManager/

###Background###

Prior to HubConnectionManager, if I happened to launch a client applicaiton when its corresponding SignalR service was unavailable, I'd have to restart the whole application for it to recover. Now, with HubConnectionManager, I can ensure that the client will attempt to re-establish a connection with the server. And it works!

Furthermore, wrapping the HubConnection in an IHubConnectionManager interface means that mocking connection state is easy. Hooray for comprehensive unit testing!

###Usage###

1. Create an instance of HubConnectionManager through the static GetHubConnectionManager method, providing the url of your SignalR endpoint:

HubConnectionManager connectionManager = HubConnectionManager.GetHubConnectionManager("http://localhost:6789");

2. Create you IHubProxy via the CreateHubProxy method, passing in the name of your Hub:

IHubProxy clientProxy = connectionManager.CreateHubProxy("ClientHub");

3. Initialize the Manager via Initialize() method:

connectionManager.Initialize();

That's it! As long as you have a reference to the HubConnectionManager like you'd have a reference to your HubConnection in the past, it should work just the same.

###Additional Functionality###

I also expose many of the events and properties of HubConnection:

####Events####

• Error
• Received
• Closed
• Reconnecting
• Reconnected
• ConnectionSlow
• StateChanged

####Properties####

• State

hubconnectionmanager's Issues

Client Disconnect (by choice!)

As of 1.0.2, the Manager will always try and reconnect any time that it detects the Closed event. Probably need to prevent this. Users may want to eventually disconnect ;)

SignalR.Server closes unexpectedly on restart

When running SignalR.Server and SignalR.Client together for testing, it seems like the server will run fine for a while, but if I restart the server to test the Client's ability to reconnect, the Server will unexpectedly shut down after a short period.

Not sure if I am fat-fingering a key and causing it to close, or something is being disposed prematurely and causing the application to crash.

HubConnectionManager doesn't retry to perform an initial connection when server does not exist

The scenario is:

SignalR Server is down for upgrade/maintenance
Client tries to connect to SignalR Server initially.

workaround:
wrap _HubConnectionManager.Initialize(); in a try...catch... block that squelches the error.

Wondering if this is the best case, or if we should squelch it within the HubConnectionManager class itself?

Support Client SSL Certificates

There should be a method to expose the ability of providing the Client SSL Certificate to the connection.

Extension Method for converting an OAuth access token to a cookie, then adding it to the Hub Connection

Not sure how helpful this is/will be:

    public static class HubConnectionExtensions {
        public async static void WithOAuthToken(this HubConnection connection, Uri authUri, string accessToken) {
            var cookies = new CookieContainer();
            var clientHandler = new System.Net.Http.HttpClientHandler { 
                UseCookies = true, 
                CookieContainer = cookies 
            };
            var client = new HttpClient(clientHandler) {
                BaseAddress = new Uri(connection.Url)
            };
            client.SetBearerToken(accessToken);
            var result = await client.GetAsync(authUri);
            result.EnsureSuccessStatusCode();

            connection.CookieContainer = cookies;
        }
    }

Resubscribing to groups

Looking for input on what happens after a disconnect (not just connection interruption, but after the DisconnectTimeout period ends and the client disconnects).

According to ASP.NET documentation, all Group subscriptions are lost after a disconnect. Just looking for input on what the best course of action should be on the part of the HubConnectionManager after this happens.

Should it facilitate re-subscribing to those groups after connection is re-established?

Currently, I am doing this manually on the client by subscribing to the StateChanged event and calling a method on the Hub that subscribes again to the appropriate groups.

Support multiple targets

Support 4.0, 4.5, PCL targets.