Realtime web experience with signal r
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This document summarizes a presentation about SignalR, a library for adding real-time web functionality to applications. It discusses techniques for real-time web experiences like polling, long polling, and web sockets. SignalR is presented as an abstraction layer that can use the best available connection method and supports cross-platform development. Key features of SignalR like Hubs, Groups, and self-hosting are explained. The presentation provides examples of how to use SignalR on both the client and server side and discusses scaling out with Redis.
Realtime web experience with signal r
- 1. SELA DEVELOPER PRACTICE May 5-9, 2013 Ran Wahle Real time Web experience with signalR
- 2. Agenda • “Real Time” web techniques • What is signalR • SignalR protocol • Hubs • Groups and private messages • .Net client • Self Hosting • Scaleout
- 4. Polling
- 5. Long Polling
- 8. Web Socket Web Socket Request TCP Socket ServerClient
- 9. Web socket • Actual TCP socket between server and client • HTML5 standard • Supported by Windows server 2012 / Windows 8 • Supported by IE10+, Chrome, Firefox, Opera and more
- 10. Web socket in code Server (C#): public void ProcessRequest(HttpContext context) { HttpContext.Current. AcceptWebSocketRequest (new ChatWebSocketHandler()); context.Response.StatusCode =(int)HttpStatusCode.SwitchingProtocols; } Client: (javascript) var websocket = new window.WebSocket(“ws://<web socket url>”);
- 11. Web socket in code Server (C#) public class MyWebSocketHandler : WebSocketHandler public override void OnOpen() public override void OnError() public override void OnMessage(string message) Client (Javascript) websocket.onopen = function () { …} websocket.onerror = function(data) {…} websocket.onmessage = function (event) {
- 12. WebSocket is not enough • Not all servers support web sockets • Not all network components support web sockets • It’s API is limited
- 13. What do we need? • Code once, deploy everywhere • As cross-platform as possible • Simple API to work with
- 14. What is signalR • Open source project • Abstraction layer over connection technique • Can be self-hosted • Call client methods from the server ServerSentEvents = Polling ForeverFrames Long-Polling WebSocket
- 15. So, why not WebSocket WebSocket • Good performance • Strict prerequisites • Limited API SignalR • Abstraction layer • Rich API • Supports WebSocket
- 16. Getting started “Every time I see live-coding I get down on my knees and pray” Anonymous narrator
- 17. Protocol Negotiate request Negotiate response Connection phase Client Server
- 19. Hub • Abstraction over signalR connection • Service-like API • Call clients methods from the server
- 20. Hub Server (C#) public void ServerMethod(args) { ….. } private void SendToClient() { Clients.All.doSomething(args); } Client (Javascript) hub.server.serverMethod(args); hub.client.doSomething = function(args) { … };
- 21. Private messages • You can use connection ID • You can access a particular client by it Clients.Client(connectionId).sendMessage(message)
- 22. Groups • Part of Hub API • Stored on client • Not persistent Groups.Add(Context.ConnectionId, groupName); Clients.Group(groupName).invokeSomeClientMethod(args…);
- 23. .Net client _connection = new HubConnection(“Server Url"); IHubProxy proxy = connection.CreateHubProxy(“Hub Name"); _connection.Start().ContinueWith( //define proxies ); //invoke server methods _proxy.Invoke(“HubServerMethod“ , args…));
- 24. Self hosting • Three NuGet packages to install Microsoft.Owin.Hosting Microsoft.Owin.Host.HttpListener Microsoft.AspNet.SignalR.Owin • Create class with Configuration method. • Map hub in the Configuration method • Use the class as a type parameter to WebApplication.Start
- 25. ScaleOut with Redis • Install Redis for Linux or Clone the windows porting • Add One line of code GlobalHost.DependencyResolver.UseRedis(“<server>", <port>, “<password>", “< storagekey>"); • On Windows – run redis from command line • Your app is ready to scaleout
- 26. What have we seen today? • Real time experience is more than just polling • Using signalR can use the best available technique • It can be self hosted • It can scale out • It has several clients
- 27. Other resources •http://www.asp.net/signalr •http://signalr.net/ •Twitters:@signalr @DamianEdwards @davidfowl and @DavianFowlwards •http://blogs.Microsoft.co.il/blogs/ranw