asp.net-mvc SignalR + 通过操作方法将消息发布到集线器

SignalR + posting a message to a Hub via an action method

提问by ollifant

I am using the hub- feature of SignalR (https://github.com/SignalR/SignalR) to publish messages to all subscribed clients:

我正在使用 SignalR ( https://github.com/SignalR/SignalR)的集线器功能向所有订阅的客户端发布消息：

public class NewsFeedHub : Hub
public void Send(string channel, string content)
{
    Clients[channel].addMessage(content);
}

This works fine when calling "Send" via Javascript, but I would also like the web application to publish messages (from within an ASP.NET MVC action method). I already tried instantiating a new object ob NewsFeedHub and calling the Send method, but this results in an error (as the underlying "Connection" of the Hub is not set). Is there a way to use the Hub without a connection?

这在通过 Javascript 调用“发送”时工作正常，但我也希望 Web 应用程序发布消息（从 ASP.NET MVC 操作方法中）。我已经尝试实例化一个新对象 ob NewsFeedHub 并调用 Send 方法，但这会导致错误（因为未设置集线器的底层“连接”）。有没有办法在没有连接的情况下使用集线器？

回答by Tim B James

Please note that the SignalR API has changed multiple times since this question was asked. There is a chance that some answers will become out of date. This does not mean that they should be down-voted as they were correct at the time of writing

请注意，自提出此问题以来，SignalR API 已多次更改。有些答案可能会过时。这并不意味着它们应该被否决，因为它们在撰写本文时是正确的

There is another updated answer for this, as seen in the SignalR Wiki

对此还有另一个更新的答案，如SignalR Wiki 中所示

c#

C＃

Public ActionResult MyControllerMethod()
{
    var context = GlobalHost.ConnectionManager.GetHubContext<MyHub>();
    context.Clients.All.methodInJavascript("hello world");
    // or
    context.Clients.Group("groupname").methodInJavascript("hello world");
}

vb.net

网络

Public Function MyControllerMethod() As ActionResult
    Dim context = GlobalHost.ConnectionManager.GetHubContext(Of MyHub)()
    context.Clients.All.methodInJavascript("hello world")
    '' or
    context.Clients.Group("groupname").methodInJavascript("hello world")
End Function

Update

更新

This code has been updated. Follow http://www.asp.net/signalr/overview/signalr-20/hubs-api/hubs-api-guide-serverfor changes.

此代码已更新。按照http://www.asp.net/signalr/overview/signalr-20/hubs-api/hubs-api-guide-server进行更改。

If you are using DI container

如果您使用的是 DI 容器

If you are using a DI container to wire up your hubs, get IConnectionManagerfrom your container, and call GetHubContexton that connectionManager.

如果您使用 DI 容器来连接您的集线器，请IConnectionManager从您的容器中获取并调用GetHubContext该 connectionManager。

回答by DDan

2018 February, Short and simple solution

2018 年 2 月，简短而简单的解决方案

For solving this I usually design my hubs in the following way:

为了解决这个问题，我通常按以下方式设计我的集线器：

public class NewsFeedHub : Hub 
{
    private static IHubContext hubContext = GlobalHost.ConnectionManager.GetHubContext<NewsFeedHub>();

    // Call this from JS: hub.client.send(channel, content)
    public void Send(string channel, string content)
    {
        Clients.Group(channel).addMessage(content);
    }

    // Call this from C#: NewsFeedHub.Static_Send(channel, content)
    public static void Static_Send(string channel, string content)
    {
        hubContext.Clients.Group(channel).addMessage(content);
    }

}

So it's easy to call from Javascript and from back-end code as well. The two methods are resulting in the same event at the client.

因此，从 Javascript 和后端代码调用也很容易。这两种方法在客户端产生相同的事件。

回答by Judah Gabriel Himango

update 2012: This answer is old, too! SignalR's public API is in constant flux, it seems. Tim B James has the new, proper API usage as of July 2012.

2012 年更新：这个答案也很旧！SignalR 的公共 API 似乎在不断变化。截至 2012 年 7 月，Tim B James 拥有新的、正确的 API 用法。

update 2019Don't use this answer anymore. New versions of SignalR that work on AspNetCore should refer to the accepted answer by Tim B James, or other up-voted answers. I'm leaving this answer here for history's sake.

更新 2019不要再使用这个答案了。在 AspNetCore 上工作的 SignalR 的新版本应该参考 Tim B James 接受的答案，或其他投票的答案。为了历史的缘故，我将这个答案留在这里。

---

---

The currently accepted answer from Mike is old, and no longer works with the latest version of SignalR.

Mike 当前接受的答案是旧的，不再适用于最新版本的 SignalR。

Here's an updated version that shows how to post a message to a hub from an MVC controller action:

这是一个更新版本，显示了如何从 MVC 控制器操作向集线器发布消息：

public ActionResult MyControllerMethod() 
{
     // Important: .Resolve is an extension method inside SignalR.Infrastructure namespace.
     var connectionManager = AspNetHost.DependencyResolver.Resolve<IConnectionManager>();
     var clients = connectionManager.GetClients<MyHub>();

     // Broadcast to all clients.
     clients.MethodOnTheJavascript("Good news!");

     // Broadcast only to clients in a group.
     clients["someGroupName"].MethodOnTheJavascript("Hello, some group!");

     // Broadcast only to a particular client.
     clients["someConnectionId"].MethodOnTheJavascript("Hello, particular client!");
 } 

回答by J45

Following on from DDan's answer you can create an overloaded static method and keep common logic in one method - I use this pattern

继 DDan 的回答之后，您可以创建一个重载的静态方法并将通用逻辑保留在一个方法中 - 我使用这种模式

public class ChatHub : Hub
{
    private static IHubConnectionContext<dynamic> GetClients(ChatHub chatHub)
    {
        if (chatHub == null)
            return GlobalHost.ConnectionManager.GetHubContext<ChatHub>().Clients;
        else
            return chatHub.Clients;
    }

    // Call from JavaScript
    public void Send(string message)
    {
        Send(message, this);
    }

    // Call from C# eg: Hubs.ChatHub.Send(message, null);
    public static void Send(string message, ChatHub chatHub)
    {
        IHubConnectionContext<dynamic> clients = GetClients(chatHub);
        // common logic goes here 
        clients.All.receiveSend(message);
    }
}

Then from your controller you can use

然后从你的控制器你可以使用

Hubs.ChatHub.Send(arg1, null);