ITCamp 2012 - Alessandro Pilotti - Web API, web sockets and RSignal
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This document summarizes a presentation about building modern web sites with ASP.Net Web API, WebSockets, and SignalR. The presentation introduces these technologies and how they can be used to build single page applications with real-time functionality. It provides examples of using ASP.Net Web API to create RESTful APIs, SignalR for persistent connections and messaging, and WebSockets for bidirectional communication. The presentation demonstrates how these tools allow building applications that approach the usability of desktop applications.
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![ASP.Net Web API routing Mobile &
Development
routes.MapHttpRoute(
name: "API Default",
routeTemplate: "api/{controller}/{id}",
defaults: new { id = RouteParameter.Optional }
);
• Avoids conflicts with MVC routing
• Naming Convention
– GetAllProducts, DeleteProduct, etc
• Explicit action attributes:
– [HttpGet], [HttpPost], [HttpPut], [HttpDelete], [NonAction]
• User "api/{controller}/{action}/{id}” for RPC style routing
– Needs explicit verb attributes
@ itcampro # itcamp12 Premium conference on Microsoft technologies](https://image.slidesharecdn.com/itcamp2012-alessandropilotti-webapiwebsocketsandrsignal-120618041128-phpapp01/85/ITCamp-2012-Alessandro-Pilotti-Web-API-web-sockets-and-RSignal-14-320.jpg)
![Look Mama, no global.asax routes Mobile &
Development
• SignalR’s AspNetBootStrapper defines
– [assembly:
PreApplicationStartMethod(typeof(AspNetBootstrapper),
"Initialize")]
– Initialize calls: RouteTable.Routes.MapHubs();
• Mapping the /signalr route
• No need for:
– Explicit global.asax route mapping
– Web.config settings
@ itcampro # itcamp12 Premium conference on Microsoft technologies](https://image.slidesharecdn.com/itcamp2012-alessandropilotti-webapiwebsocketsandrsignal-120618041128-phpapp01/85/ITCamp-2012-Alessandro-Pilotti-Web-API-web-sockets-and-RSignal-28-320.jpg)
![In ASP.Net – updated support Mobile &
Development
• Install-Package Microsoft.WebSockets
RouteTable.Routes.Add(new ServiceRoute("connect",
new WebSocketServiceHostFactory(),
typeof(GameService)));
public class GameService : WebSocketService
{
private static GameServer server = new GameServer();
private GameConnection connection;
public override void OnOpen()
{
string nickname = QueryParameters["nickname"];
int gameSize = int.Parse(QueryParameters["gamesize"]);
connection = server.JoinGame(this, nickname, gameSize);
}
public override void OnMessage(string message)
{
connection.ProcessCommand(message);
}
protected override void OnClose()
{
if(connection != null)
connection.Disconnect();
}
}
}
@ itcampro # itcamp12 Premium conference on Microsoft technologies](https://image.slidesharecdn.com/itcamp2012-alessandropilotti-webapiwebsocketsandrsignal-120618041128-phpapp01/85/ITCamp-2012-Alessandro-Pilotti-Web-API-web-sockets-and-RSignal-40-320.jpg)
ITCamp 2012 - Alessandro Pilotti - Web API, web sockets and RSignal
- 1. Building modern web sites with ASP .Net Web API, WebSockets and RSignal Alessandro Pilotti MVP ASP.Net / IIS Windows Azure Insider @alexpilotti @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 2. ITCamp 2012 sponsors Mobile & Development @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 3. Agenda Mobile & Development • ASP.Net Web API • SignalR • WebSocket @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 4. What’s the deal? Mobile & Development • The web app designer’s holy grail: – Reach the usability level of a desktop app • The web app designer’s curse: – Lack of standard API on the browser’s side • Until recently the only way out was a RIA framework: – Flash / Silverlight @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 5. HTML5 Mobile & Development • HTML5 is changing the game • Great set of new browser features: – Application cache – Web storage – WebSockets – WebWorkers – Geolocation – Drag&Drop – Multiple file uploads – Inline SVG – History management – … and that Video thing @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 6. Javascript? Mobile & Development • Javascript is getting a huge boost – There’s more than meets the eye – Its prototyping nature and flexibility is great • The rest sucks • An enormous amount of frameworks are available today, e.g: – JQuery / JQuery UI – Knockout.js – Backbone.js – Underscore.js – History.js – …And a gazillion more @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 7. SPA Mobile & Development • Single Page Applications – A single HTML is loaded in the browser – History (aka back button) is managed via Javascript – Templates are used to load and render in the DOM content on demand • Some Ajax might be useful for that – Offline usage • Application cache • Web storage @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 8. And how do we access Data? Mobile & Development • Web pages communicate with the server via asynchronous calls – XmlHttpRequest (as in ajax) – JSON serialization • Way faster than XML • Originally decoded with “eval” • Modern browsers provide native encoding / deconding – JSON.parse(…) / JSON.stringify(…) – Even faster! – RESTful APIs – WebSockets • Where supported @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 9. Great advantages Mobile & Development • Faster web sites • Lower traffic • Clear separation – UI – Services / BL • Enhanced testability – Unit tests for the server API – MVVM in Javascript (e.g. Knockout.js) • Enhanced portability – E.g. Mobile UI @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 10. ASP.Net Web API Mobile & Development • ASP.Net Web API – Comes with MVC4 – Provides a new RESTful Web API framework – ODATA support – Very easy – Great IoC support – EF integration (DbDataController<T>) – Can be also installed on MVC3 or Web Forms • Install-Package AspNetWebApi • All the ASP.Net Stack is open source!! – http://aspnetwebstack.codeplex.com/ • Alternative: WCF – RESTful support – More control • Complicated bindings configuration @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 11. RESTful APIs Mobile & Development • Use of HTTP verbs: – GET – POST – PUT – DELETE • Great for CRUD operations • Errors use HTTP semantics – E.g. not found => 404 • Uses custom routing • A lot less bloated than SOAP @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 12. RESTful APIs example Mobile & Development Action HTTP verb Relative URI Get a list of all products GET /api/products Get a product by ID GET /api/products/id Get a product by category GET /api/products?category=category Create a new product POST /api/products Update a product PUT /api/products/id Delete a product DELETE /api/products/id @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 13. jQuery example Mobile & Development jQuery does all the dirty job, the result is neat and clean: $.getJSON( "api/products", function(data) { $.each(data, function(index, value) { $("#products").append('<li>' + value.Name + '</li>'); }); }); @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 14. ASP.Net Web API routing Mobile & Development routes.MapHttpRoute( name: "API Default", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); • Avoids conflicts with MVC routing • Naming Convention – GetAllProducts, DeleteProduct, etc • Explicit action attributes: – [HttpGet], [HttpPost], [HttpPut], [HttpDelete], [NonAction] • User "api/{controller}/{action}/{id}” for RPC style routing – Needs explicit verb attributes @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 15. HttpMessageHandler Mobile & Development • ASP.Net Web API is based on a pipeline • Inherit from DelegatingHandler to create your handlers – E.g. check an API key • Add with: – config.MessageHandlers.Add(new ApiKeyHandler()); @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 16. ODATA + Web API Mobile & Development • Open Data Protocol – A web protocol for querying and updating data • Enable ODATA queries on your Web API – Just return an IQueriable<T> • Examples – http://localhost:1702/api/Products?$filter=Enabled%2 0eq%20true – http://localhost:1702/api/Products?$orderby=Name% 20desc – http://localhost:1702/api/Products?$filter=startswith( Name,’whatever') @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 17. CURL Mobile & Development • Great tool for troubleshooting • curl -i -H "Accept: application/json" http://localhost:1823/api/Products • curl -i -H "Content-Type: application/json" -H "Accept: application/json" -X POST -d @data.json http://localhost:1823/api/Product @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 18. WEB API DEMO @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 19. SignalR Mobile & Development • A framework that provides some magic for: – Persistent connections • LongPolling • WebSockets • Examples: chat, stock ticker updates – Dynamic proxy generation for Javascript code • Hubs – JSON serialization • Asynchronous model • Supports self hosting • Unrelated to MVC or Web Forms • Install-package SignalR – Or: https://github.com/SignalR/SignalR @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 20. Long Polling Mobile & Development A way to simulate push data connections 1. The client connects via HTTP 2. The server waits for available data 3. The server sends the response 4. Back to step one @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 21. Persistent connections (server) Mobile & Development public class MyConnection : PersistentConnection { protected override Task OnReceivedAsync(IRequest request, string connectionId, string data) { // Broadcast data to all clients return Connection.Broadcast(data); } } Routing setup in global.asax: RouteTable.Routes.MapConnection<MyConnection>("echo", "echo/{*operation}"); @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 22. Persistent connections (client) Mobile & Development $(function () { var connection = $.connection('/echo'); connection.received(function (data) { $('#messages').append('<li>' + data + '</li>'); }); connection.start(); $("#broadcast").click(function () { connection.send($('#msg').val()); }); }); @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 23. PersistentConnection API Mobile & Development • Task OnConnectedAsync(IRequest request, string connectionId) • Task OnReconnectedAsync(IRequest request, IEnumerable groups, string connectionId) • Task OnReceivedAsync(IRequest request, string connectionId, string data) • Task OnDisconnectAsync(string connectionId) • Task OnErrorAsync(Exception error) @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 24. IConnection API Mobile & Development • Task Broadcast(object value) • Task Send(string signal, object value) @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 25. External broadcasts Mobile & Development var context = GlobalHost.ConnectionManager. GetConnectionContext<MyEndPoint>(); context.Connection.Broadcast(message); • Useful to send messages starting from a server action @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 26. Hub (server) Mobile & Development public class Chat : Hub { public void Send(string message) { // Call the addMessage method on all clients Clients.addMessage(message); } } • Methods can have any name, the client resolves the names via proxy • Clients is a dynamic object – addMessage is defined in Javascript!! @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 27. Hub (client) Mobile & Development var chat = $.connection.chat; // Declare a function on the chat hub so the server can invoke it chat.addMessage = function(message) { $('#messages').append('<li>' + message + '</li>'); }; $("#broadcast").click(function () { // Call the chat method on the server chat.send($('#msg').val()) .done(function() { console.log('Success!'); }) .fail(function(e) { console.warn(e); }); }); // Start the connection $.connection.hub.start(); @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 28. Look Mama, no global.asax routes Mobile & Development • SignalR’s AspNetBootStrapper defines – [assembly: PreApplicationStartMethod(typeof(AspNetBootstrapper), "Initialize")] – Initialize calls: RouteTable.Routes.MapHubs(); • Mapping the /signalr route • No need for: – Explicit global.asax route mapping – Web.config settings @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 29. External broadcasts Mobile & Development var context = GlobalHost.ConnectionManager. GetHubContext<MyHub>(); context.Clients.say(message); @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 30. IIS setup for high loads Mobile & Development • appcmd.exe set config /section:serverRuntime /appConcurrentRequestLimit:100000 • In %windir%Microsoft.NETFrameworkv4.0.30319 aspnet.config – maxConcurrentRequestsPerCPU="20000” • In %windir%Microsoft.NETFrameworkv4.0.30319 Configmachine.config – <processModel autoConfig="false" requestQueueLimit="250000" /> technologies @ itcampro # itcamp12 Premium conference on Microsoft
- 31. SIGNALR DEMO @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 32. WebSockets Mobile & Development • TCP/IP communication style model – Handshake resembles HTTP • Interoperable • Standard W3C (still in draft) – Older browsers support old versions • Bidirectional communications • Supports cross domain access! @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 33. Handshake Mobile & Development Request: GET /mychat HTTP/1.1 Host: server.example.com Upgrade: websocket Connection: Upgrade Sec-WebSocket-Key: x3JJHMbDL1EzLkh9GBhXDw== Sec-WebSocket-Protocol: chat Sec-WebSocket-Version: 13 Origin: http://example.com Response: HTTP/1.1 101 Switching Protocols Upgrade: websocket Connection: Upgrade Sec-WebSocket-Accept: HSmrc0sMlYUkAGmm5OPpG2HaGWk= Sec-WebSocket-Protocol: chat @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 34. Javascript Mobile & Development • Url: ws://yourhost/etc – wss: when used with SSL/TLS var socket = new WebSocket('ws://game.example.com:12010/update s'); socket.onopen = function () { setInterval(function() { if (socket.bufferedAmount == 0) socket.send(getUpdateData()); }, 50); }; @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 35. Minimum requirements Mobile & Development • IE 10 • Chrome 4 • Firefox 4 • Safari 5 • Opera 11 • Server: IIS 8 @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 36. Proxy support Mobile & Development • Proxies tipically don’t recognize WebSocket traffic • By using SSL/TLS the problem is mitigated – Client uses HTTP CONNECT in this case @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 37. IIS 8 – enable WebSockets feature Mobile & Development @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 38. WCF 4.5 – HTTP Activation Mobile & Development @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 39. WCF 4.5 Mobile & Development @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 40. In ASP.Net – updated support Mobile & Development • Install-Package Microsoft.WebSockets RouteTable.Routes.Add(new ServiceRoute("connect", new WebSocketServiceHostFactory(), typeof(GameService))); public class GameService : WebSocketService { private static GameServer server = new GameServer(); private GameConnection connection; public override void OnOpen() { string nickname = QueryParameters["nickname"]; int gameSize = int.Parse(QueryParameters["gamesize"]); connection = server.JoinGame(this, nickname, gameSize); } public override void OnMessage(string message) { connection.ProcessCommand(message); } protected override void OnClose() { if(connection != null) connection.Disconnect(); } } } @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 41. WEBSOCKETS DEMO @ itcampro # itcamp12 Premium conference on Microsoft technologies
- 42. Q&A @ itcampro # itcamp12 Premium conference on Microsoft technologies