Xamarin Form using ASP.NET Core SignalR client
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The document discusses the integration of ASP.NET Core SignalR with Xamarin.Forms to enable real-time communication in cross-platform applications using a .NET Standard 2.0 C# client library. It outlines key features of ASP.NET Core SignalR, including transport mechanisms, hub concepts, and authentication, while providing guidance on implementing it in Xamarin.Forms projects. Additional resources and demo code links are provided for developers to explore further.
Xamarin Form using ASP.NET Core SignalR client
- 1. ASP.NET Core SignalR & Xamarin.Forms Connect ASP.NET Core SignalR service via .NET Standard 2.0 C# client library in Xamarin.Forms
- 2. ASP.NET Core SignalR • A re-designed SignalR(http://signalr.net/) library for ASP.NET Core 2.1 to provide real-time communication: http://github.com/aspnet/signalr • Not compatible with old ASP.NET SignalR. • Existing Application that use ASP.NET SignalR or ASP.NET Core SignalR: • Office 365 real-time document co-authoring: http://bit.ly/2KIZjrb • Visual Studio Live Share: http://bit.ly/2Nl8Aak
- 3. ASP.NET Core SignalR Features • Multiple transport mechanism: • Websocket: http://bit.ly/2MLVwtL • Server-Send event: http://bit.ly/2KuvkXW • Long Polling: http://bit.ly/2lOvg6t • Hub concepts for client & server communication: • Hub protocols: text based JSON & binary based MessagePack ( http://msgpack.org/ ) • Support 3 RPC style: 1. Server RPC call 2. Server Streaming RPC call 3. Server Call Client defined function
- 4. ASP.NET Core SignalR Features • Hub Protocol spec is opened: http://github.com/aspnet/SignalR/blob/master/specs/HubProtocol.m d • Provide many language implementation of client library: • JavaScript: http://www.npmjs.com/package/@aspnet/signalr • C#: http://www.nuget.org/packages/Microsoft.AspNetCore.SignalR.Client/ • C++ & Java Client are under development and will release stable version with ASP.NET Core 2.2 timeline. • 3rd Party: • Swift : http://github.com/moozzyk/SignalR-Client-Swift • RxJs enabled Js client: http:///www.npmjs.com/package/@ssv/signalr-client
- 5. ASP.NET Core SignalR Features • Hub support ASP.NET Core Authentication mechanism • Cookie • JWT Auth Token • Service instance can be scale-out using Redis on-premises, using Azure SignalR Service(https://aka.ms/signalr_service ) in cloud. • Note: ASP.NET SignalR can scale-out via Azure Service Bus, but there’s no plan for ASP.NET Core SignalR right now: https://github.com/aspnet/SignalR/issues/1676
- 6. Xamarin & ASP.NET Core SignalR • Using ASP.NET Core SignalR technology, we can build a cross platform/device broadcasting system via Xamarin. • Demo code: http://bit.ly/2KHv57D
- 7. Xamarin.Forms as Core SignalR client Using following Nuget Package in Xamarin.Forms project: • Microsoft.AspNetCore.SignalR.Client: https://www.nuget.org/packages/Microsoft.AspNetCore.SignalR.Client/ • Microsoft.Extensions.Logging.Console: (for iOS & Android logging) https://www.nuget.org/packages/Microsoft.Extensions.Logging.Console/ • Microsoft.Extensions.Logging.Debug: (for UWP logging) https://www.nuget.org/packages/Microsoft.Extensions.Logging.Debug/ • System.Threading.Channels: (for invoke Server Streaming RPC call) https://www.nuget.org/packages/System.Threading.Channels/
- 8. Xamarin.Forms as Core SignalR client • Hub: a connection joint that client & sever can call their defined methods mutually. Server Client #1 Client #2 Client #3 Hub
- 9. Xamarin.Forms as Core SignalR client • On Client side, use “HubConnection(http://bit.ly/2tRduE6)” to access the Server Method defined in Hub. • To create HubConnection object, using “HubConnectionBuilder(http://bit.ly/2MLLGYC)” to create. • HubConnectionBuilder has many Fluent-API style extension method to configure it. (ASP.NET Core configuration style)
- 11. Xamarin.Forms as Core SignalR client • This kind of “Code as Configuration” coding style is very modifiable based on demand, and can be refactored to a clear style using Action Delegate: http://www.tutorialsteacher.com/csharp/csharp-action-delegate
- 12. Xamarin.Forms as Core SignalR client • Once HubConneciton instance is created, call StartAsync() to connect to remote ASP.NET Core SignalR server, call StopAsync() or DisposeAsync() to tear down connection, HubConnection object cannot be re-used, must create it every time when starting a new connection.
- 13. Xamarin.Forms as Core SignalR client • Server RPC call : (http://bit.ly/2KKDXN8) • Use HubConnectionExtensions.InvokeAsync<TResult>() extension method(http://bit.ly/2MOpy03 ) to get RPC call result.
- 14. Xamarin.Forms as Core SignalR client • Server Streaming RPC call: http://bit.ly/2tQLbp4 • Use HubConnectionExtensions.StreamAsChannelAsync<TResult>() extension method (http://bit.ly/2zfC1bc), • Which needs additional New Type called “ChannelReader(http://bit.ly/2MJARXi)” from .NET Core runtime, that is not documented in official docs yet. Channel(http://bit.ly/2KJAkXG) is a kind of Data Queue that mimics Go’s “Buffered Channel(http://bit.ly/2IRo56K)” concept: https://github.com/stephentoub/corefxlab/blob/master/src/Syst em.Threading.Tasks.Channels/README.md
- 15. Xamarin.Forms as Core SignalR client • Server Streaming RPC call can be cancelled from client via Set Cancellation token parameter in HubConnectionExtensions.StreamAsChannelAsync<TResult>()
- 16. Xamarin.Forms as Core SignalR client • Server Call Client defined function: (http://bit.ly/2lT4cDf) Register client function using HubConnection.On() or HubConnectionExtensions.On(http://bit.ly/2IQ0Auw) API:
- 17. Other Notes Xamarin Client need to use latest preview of Visual Studio 2017 15.8 preview 3 or Visual Studio for Mac 7.6 preview 3: https://github.com/aspnet/Announcements/issues/305 • UWP on Windows 10 Mobile OS is not support since .NET Standard 2.0 support for Windows 10 UWP comes in 2017 Fall Creators Update. • UWP logging has to use AddDebug(), not AddConsole(). • JWT Authentication is configured on HubConnectionBuilder’s WithUrl() extension method: https://github.com/aspnet/SignalR/blob/948ebf34ece11918804f443b65c6a053dfc 8f35c/samples/JwtClientSample/Program.cs#L38 • Local debugging & testing can use ngrok(http://ngrok.com) for real device connection.
- 18. Resources • Code Magazine 2018 Jul/Aug issue: http://www.codemag.com/Magazine/Issue/JulAug18 • Official doc: http://docs.microsoft.com/en- us/aspnet/core/signalr/dotnet-client • ASP.NET Core SignalR source code repo: http://github.com/aspnet/signalr • ASP.NET Core sample code repo: http://github.com/aspnet/SignalR-samples • Build 2018 Introduction Video: https://channel9.msdn.com/Events/Build/2018/BRK2147