SignalR---DOTNET客户端

这里面有用到异步的相关知识，本人前几篇文章也简单的提到。

SignalR客户端要寄宿在.NET的客户端，必须安装Microsoft.AspNet.SignalR.Client。

如何建立一个连接
var hubConneciton=new HubConnection("http://www.contos.com/");
IHubProxy stockTickerHubProxy=hubConnection.CreateHubProxy("StockTickerHub");
stockTickerHubProxy.On<Stock>("UpdateStockPrice",stock=>Console.WrireLine("Stock update");
await hubConnection.Start();
);

Start是一个异步方法
C#
await connection.Start();
css
connection.Start().Wait();


配置连接
在建立连接之前可以做一些配置。

设置最大并发数
var hubConnection = new HubConnection("http://www.contoso.com/");
IHubProxy stockTickerHubProxy = hubConnection.CreateHubProxy("StockTickerHub");
stockTickerHubProxy.On<Stock>("UpdateStockPrice", stock => Console.WriteLine("Stock update for {0} new price {1}", stock.Symbol, stock.Price));
ServicePointManager.DefaultConnectionLimit = 10;
await hubConnection.Start();
默认最大并发数为2。

添加连接字符串
客户端
var querystringData = new Dictionary<string, string>();
querystringData.Add("contosochatversion", "1.0");
var connection = new HubConnection("http://contoso.com/", querystringData);

服务端
public class StockTickerHub : Hub
{
    public override Task OnConnected()
    {
        var version = Context.QueryString["contosochatversion"];
        if (version != "1.0")
        {
            Clients.Caller.notifyWrongVersion();
        }
        return base.OnConnected();
    }
}

设置传输方法
var hubConnection = new HubConnection("http://www.contoso.com/");
IHubProxy stockTickerHubProxy = hubConnection.CreateHubProxy("StockTickerHub");
stockTickerHubProxy.On<Stock>("UpdateStockPrice", stock => Console.WriteLine("Stock update for {0} new price {1}", stock.Symbol, stock.Price));
await hubConnection.Start(new LongPollingTransport());

关于传输方式在Microsoft.AspNet.SignalR.Client.Transports命名空间下。
LongPollingTransport、ServerSentEventsTransport、WebSocketTranspor、WebSocketTranspor。
ForevenFrame不被包含在内，因为它只在浏览器中使用。

指定HTTP头信息
hubConnection = new hubConnection("http://www.contoso.com/");
connection.Headers.Add("headername", "headervalue");
IHubProxy stockTickerHubProxy = hubConnection.CreateHubProxy("StockTickerHub");
stockTickerHubProxy.On<Stock>("UpdateStockPrice", stock => Console.WriteLine("Stock update for {0} new price {1}", stock.Symbol, stock.Price));
await connection.Start();

指定客户端的证书
使用connection对象的AddClientCertificate方法。
hubConnection = new hubConnection("http://www.contoso.com/");
hubConnection.AddClientCertificate(X509Certificate.CreateFromCertFile("MyCert.cer"));
IHubProxy stockTickerHubProxy = hubConnection.CreateHubProxy("StockTickerHub");
stockTickerHubProxy.On<Stock>("UpdateStockPrice", stock => Console.WriteLine("Stock update for {0} new price {1}", stock.Symbol, stock.Price));
await connection.Start();



创建Hub代理
服务端
public class StockTickerHub : Hub

[HubName("stockTicker")]
public class StockTickerHub : Hub

客户端
var hubConnection = new HubConnection("http://www.contoso.com/");
IHubProxy stockTickerHubProxy = hubConnection.CreateHubProxy("StockTickerHub");
stockTickerHubProxy.On<Stock>("UpdateStockPrice", stock => Console.WriteLine("Stock update for {0} new price {1}", stock.Symbol, stock.Price));
await hubConnection.Start();

var hubConnection = new HubConnection("http://www.contoso.com/");
IHubProxy stockTickerHubProxy = hubConnection.CreateHubProxy("stockTicker");
stockTickerHubProxy.On<Stock>("UpdateStockPrice", stock => 
    Console.WriteLine("Stock update for {0} new price {1}", stock.Symbol, stock.Price));
await hubConnection.Start();



定义客户端方法
使用代理的On方法去注册事件处理器，方法名符合驼峰命名法。
服务端的Client.All.UpdateStockPrice方法名将会匹配客户端的
udateStockPrice、updatestockprice、UpdateStockPrice方法。

没有参数的方法
服务端
public class StockTickerHub : Hub
{
    public void NotifyAllClients()
    {
         Clients.All.Notify();
    }
}

客户端
var hubConnection = new HubConnection("http://www.contoso.com/");
IHubProxy stockTickerHubProxy = hubConnection.CreateHubProxy("StockTickerHub");
stockTickerHub.On("notify", () =>
    // Context is a reference to SynchronizationContext.Current
    Context.Post(delegate
    {
        textBox.Text += "Notified!
";
    }, null)
);
await hubConnection.Start();

有参数的方法
使用On方法的泛型On<T>指定参数的类型。
服务端
public void BroadcastStockPrice(Stock stock)
{
    context.Clients.Others.UpdateStockPrice(stock);
}

public class Stock
{
    public string Symbol { get; set; }
    public decimal Price { get; set; }
}

客户端
stockTickerHubProxy.On<Stock>("UpdateStockPrice", stock => 
    // Context is a reference to SynchronizationContext.Current
    Context.Post(delegate
    {
        textBox.Text += string.Format("Stock update for {0} new price {1}
", stock.Symbol, stock.Price);
    }, null)
);

也可以为动态对象
stockTickerHubProxy.On("UpdateStockPrice", stock => 
    // Context is a reference to SynchronizationContext.Current
    Context.Post(delegate
    {
        textBox.Text += string.Format("Stock update for {0} new price {1}
", stock.Symbol, stock.Price);
    }, null)
);
不通过On的泛型指定参数类型。



移除方法
C#
var updateStockPriceHandler = stockTickerHubProxy.On<Stock>("UpdateStockPrice", stock => 
    Context.Post(delegate
    {
        textBox.Text += string.Format("Stock update for {0} new price {1}
", stock.Symbol, stock.Price);
    }, null)
);

css
updateStockPriceHandler.Dispose();




客户端调用服务端的方法
使用Hub代理的Invoke方法。

没有返回值
服务端
public class StockTickerHub : Hub
{
    public void JoinGroup(string groupName)
    {
        Groups.Add(Context.ConnectionId, groupName); 
    }
}

客户端
stockTickerHubProxy.Invoke("JoinGroup", "SignalRChatRoom");

有返回值
服务端
public IEnumerable<Stock> AddStock(Stock stock)
{
    _stockTicker.AddStock(stock);
    return _stockTicker.GetAllStocks();
}

public class Stock
{
    public string Symbol { get; set; }
    public decimal Price { get; set; }
}


客户端
var stocks = stockTickerHub.Invoke<IEnumerable<Stock>>("AddStock", new Stock() { Symbol = "MSFT" }).Result;
foreach (Stock stock in stocks)
{
    textBox.Text += string.Format("Symbol: {0} price: {1}
", stock.Symbol, stock.Price);
}




连接生命周期事件
SignalR提供以下可以处理的连接生命周期事件：
Received：在连接上收到任何数据时触发。提供收到的数据。
ConnectionSlow：当客户端检测到缓慢或频繁丢弃的连接时引发。
Reconnecting：当底层传输开始重新连接时引发。
Reconnected：当底层运输工具重新连接时提起。
StateChanged：连接状态发生变化时触发。提供旧状态和新状态
Closed：连接断开连接时触发。

示例：
hubConnection.ConnectionSlow += () => Console.WriteLine("Connection problems.");
注册事件。




处理错误
如果没有在服务器上显式启用详细的错误消息，则SignalR在错误后返回的异常对象包含有关错误的最少信息。

服务端开启详细信息
var hubConfiguration = new HubConfiguration();
hubConfiguration.EnableDetailedErrors = true;
App.MapSignalR(hubConfiguration);

为signalR引发的错误注册事件
hubConnection.Error += ex => Console.WriteLine("SignalR error: {0}", ex.Message);

在try-catch块中处理
try
{
    IEnumerable<Stock> stocks = await stockTickerHub.Invoke<IEnumerable<Stock>>("GetAllStocks");
    foreach (Stock stock in stocks)
    {
        Console.WriteLine("Symbol: {0} price: {1}", stock.Symbol, stock.Price);
    }
}
catch (Exception ex)
{
    Console.WriteLine("Error invoking GetAllStocks: {0}", ex.Message);
}



启用客户端日记记录
通过连接对象的TrackLevel和TraceWriter属性设置。
var hubConnection = new HubConnection("http://www.contoso.com/");
hubConnection.TraceLevel = TraceLevels.All;
hubConnection.TraceWriter = Console.Out;
IHubProxy stockTickerHubProxy = hubConnection.CreateHubProxy("StockTickerHub");
stockTickerHubProxy.On<Stock>("UpdateStockPrice", stock => Console.WriteLine("Stock update for {0} new price {1}", stock.Symbol, stock.Price));
await hubConnection.Start();