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ASP.NET SignalR Basis Step by Step

2014-10-20 13:46 471 查看

SignalR 能做什么?

服务器通过HTTP连接推送数据到客户端
服务器与客户端RPC
易扩充

SignalR用什么技术传输数据？

用WebSockets，如果它是可靠的
Otherwise, using other technologies, e.g. long polling

SignalR支持什么样的数据格式？

非压缩 JSON 文本或纯文本
If you want to transfer compressed JSON or BSON or your binary data, you have to encode and decode the data (e.g. using Base64) or to implement

IJsonSerializer

by
your own logic on the server side and implement the same logic on the client side. Note that

TextReader

and

TextWriter

are
used inside SignalR. That means you have to convert your data to text before transferring anyway.

开发包

All SignalR development packages can be fetched through NuGet. Normally, you just need to fetch

Microsoft.AspNet.SignalR

(Package
ID) which contains most of the components you need, including:

Microsoft.AspNet.SignalR.Core

: 服务端组件用于创建 SignalR 终结点.

Microsoft.AspNet.SignalR.Owin

: OWIN host for SignalR.

Microsoft.AspNet.SignalR.SystemWeb

: used to host SignalR in ASP.NET
(via OWIN ASP.NET host).

Microsoft.AspNet.SignalR.Js

: JavaScript client for SignalR.
Dependencies are also included: jQuery,

Newtonsoft.Json

Microsoft.Owin.Host.SystemWeb

Microsoft.Web.Infrastructure

and
OWIN.

You could fetch other SignalR packages when you need:

Microsoft.AspNet.SignalR.Client

: .NET client for SignalR (includes
WinRT, WP8 and Silverlight5).

Microsoft.AspNet.SignalR.Redis

: Redis messaging backplane for scaling
out SignalR in web farm.

Microsoft.AspNet.SignalR.ServiceBus

: Windows Azure Service Bus messaging
backplane for scaling out SignalR in web farm.

Microsoft.AspNet.SignalR.SqlServer

: SQL Server messaging backplane
for scaling out SignalR in web farm.

Microsoft.AspNet.SignalR.Sample

: used to quickly setup a working sample
in your application.

PersistentConnection

PersistentConnection 是

服务端提供 SignalR 服务的核心类 . Let me demonstrate how to use it.

First, I create a new ASP.NET web application and use NuGet to fetch the

Microsoft.AspNet.SignalR

package.
Then,定义一个从PersistentConnection继承的新类:

public class MyConnection : PersistentConnection
{
protected override Task OnConnected(IRequest request, string connectionId)
{
string msg = string.Format(
"A new user {0} has just joined. (ID: {1})",
request.QueryString["name"], connectionId);
return Connection.Broadcast(msg);
}
protected override Task OnReceived(IRequest request, string connectionId, string data)
{
// Broadcast data to all clients
string msg = string.Format(
"{0}: {1}", request.QueryString["name"], data);
return Connection.Broadcast(msg);
}
}

OnConnected

当客户端连接服务时触发. Connections are differentiated by connection IDs (GUID). The client can pass some information
through

IRequest.QueryString

when the connection is established. We can also get other HTTP items like cookies, posted
form, headers and user principal from

IRequest

. Note all these items belong to the first request which requests to
establish the connection.

OnReceived 当客户端数据到达时触发

connectionId

tells
which connection the data comes from. The data is in text format. You have to parse it by yourself if it does not represent plain text.

PersistentConnection.Connection

provides
the 广播方法 to send a message to all connected
clients; it also provides the

Send

method
to send a message to a specific connection or a group (using the group name as

connectionId

).
Both methods support an excluded list for connections that we don’t want to send messages to.

用

MyConnection在Global.asax 文件的路由表注册

<span style="font-size:14px;">public class Global : System.Web.HttpApplication
{
protected void Application_Start(object sender, EventArgs e)
{
RouteTable.Routes.MapConnection<MyConnection>("echo", "/echo");
}
} </span>

write JavaScript in a web page to connect to our service:

<span style="font-size:14px;font-weight: normal;"><!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>SignalR Echo</title>
<script type="text/javascript" src="Scripts/jquery-2.0.3.min.js"></script>
<script type="text/javascript" src="Scripts/jquery.signalR-1.1.3.min.js"></script>
</head>
<body>
<script type="text/javascript">
function htmlEncode(value) {
return $("<div/>").text(value).html();
}

function addMsg(msg) {
$("#messages").append("<li>" + htmlEncode(msg) + "</li>");
}
$(function () {
$("#join").click(function () {
var connection = $.connection("/echo", "name=" + $("#name").val(), true);;

connection.received(function (data) {
addMsg(data);
});
connection.error(function (err) {
addMsg("Error: " + err);
});

addMsg("Connecting...");
connection.start(function () {
addMsg("Connected.");
$("#send").click(function () {
connection.send($("#msg").val());
});
});
});
});
</script>
<table>
<tr>
<td><span>Name:</span></td>
<td><input type="text" id="name" /></td>
<td><input type="button" value="Join" id="join" /></td>
</tr>
<tr>
<td><span>Message:</span></td>
<td><input type="text" id="msg" /></td>
<td><input type="button" value="Send" id="send" /></td>
</tr>
</table>
<ul id="messages"></ul>
</body>
</html>  </span>

Next let’s create a .NET client. Just create a new console application and use NuGet to
fetch the

Microsoft.AspNet.SignalR.Client

package.
In

Main

, I use the
Connection class to communicate with our service:

<span style="font-size:14px;font-weight: normal;">class Program
{
private const string ServiceUri = "http://localhost:12722/echo";
static void Main(string[] args)
{
var connection = new Connection(ServiceUri, "name=dzy");
connection.Received += connection_Received;
connection.StateChanged += connection_StateChanged;
Console.WriteLine("Connecting...");
connection.Start().Wait();
string inputMsg;
while (!string.IsNullOrEmpty(inputMsg = Console.ReadLine()))
{
connection.Send(inputMsg).Wait();
}
connection.Stop();
}
static void connection_StateChanged(StateChange state)
{
if (state.NewState == ConnectionState.Connected)
{
Console.WriteLine("Connected.");
}
}
static void connection_Received(string data)
{
Console.WriteLine(data);
}
} </span>

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