SignalR Core 之 Hubs 基本概念

services.AddSignalR();

app.UseRouting();
app.UseEndpoints(endpoints =>
{
    endpoints.MapHub<ChatHub>("/chathub");
});

public class ChatHub : Hub
{
    public Task SendMessage(string user, string message)
    {
        return Clients.All.SendAsync("ReceiveMessage", user, message);
    }
}

public Task SendMessage(string user, string message)
{
    return Clients.All.SendAsync("ReceiveMessage", user, message);
}
public Task SendMessageToCaller(string message)
{
    return Clients.Caller.SendAsync("ReceiveMessage", message);
}
public Task SendMessageToGroup(string message)
{
    return Clients.Group("SignalR Users").SendAsync("ReceiveMessage", message);
}

// 定义RFC约束
public interface IChatClient
{
    Task ReceiveMessage(string user, string message);
    Task ReceiveMessage(string message);
}
// 增加RFC编译时检查
public class ChatHub : Hub<IChatClient>
{
    public async Task SendMessage(string user, string message)
    {
        await Clients.All.ReceiveMessage(user, message);
    }
    public Task SendMessageToCaller(string message)
    {
        return Clients.Caller.ReceiveMessage(message);
    }
}

// 需要注意Hubs中Group的概念，客户端断开连接后，即使没有显示将其从Group中移除，也会自动离开加入的Group；
public override async Task OnConnectedAsync()
{
    await Groups.AddToGroupAsync(Context.ConnectionId, "SignalR Users");
    await base.OnConnectedAsync();
}
public override async Task OnDisconnectedAsync(Exception exception)
{
    await Groups.RemoveFromGroupAsync(Context.ConnectionId, "SignalR Users");
    await base.OnDisconnectedAsync(exception);
}

connection.invoke("SendMessage", user, message).catch(err => console.error(err));