SignalR解决方法从服务器获取客户端数据(SignalR workaround to get client data from server)

 我知道当服务器发出invokation时，SignalR无法从客户端返回。 在SignalR的github存储库中，我要求一个解决方法（ https://github.com/aspnet/SignalR/issues/1329 ），他们建议我通过将它从客户端发送到服务器到集线器中的另一个方法来获得结果所以使用TaskCompletionSource和一些连接元数据来捕获结果，但我仍然坚持如何做到这一点 
 
 Controller Server： 
 
[HttpPut("send/{message}")]
public async Task<IActionResult> SendMessage(string message)
{
    if (!ModelState.IsValid) return BadRequest(ModelState.Values);

    string connectionId = Request.Headers["connectionId"];
    await _chatHubContext.Clients.Client(connectionId).InvokeAsync("send");

    // Catch the call of MessageReceived and get the chat status

    return new OkObjectResult(new EmptyJsonResult() { Result = "OK" }); 

}
 
 Hub服务器 
 
public class ChatHub : Hub
{
    public Task MessageReceive(bool chatStatus)
    {
        // Tell controller that message is received
    }
}
 
 Angular 4客户端 
 
import { Component, Inject } from '@angular/core';
import { HubConnection } from '@aspnet/signalr-client';

@Component({
  selector: 'chat',
  templateUrl: './chat.component.html',
  styleUrls: ['./chat.component.css']
})
/** chat component*/
export class ChatComponent {
  hubConnection: HubConnection;
  chatStatus = false;

  /** chat ctor */
  constructor( @Inject('BASE_URL') private originUrl: string) {
    this.hubConnection = new HubConnection(`${this.originUrl}chat`);

    setInterval(() => {
      this.chatStatus = !this.chatStatus;
    },
      5000);

    this.hubConnection
      .start()
      .then(() => {
        this.hubConnection.on('send', (message: string) => {
          if (this.chatStatus) {
            //send message
          }
          this.hubConnection
            .invoke('messageReceived', this.chatStatus);
        });
      });

  }
}
 
 正如您在此代码中看到的那样，我不知道在控制器方法和Hub方法中要做什么来知道调用MessageReceive方法并让他返回将其发送回控制器请求。 

I know that SignalR can't have a return from client when invokation came from the server. On the github repository of SignalR I asked for a workaround (https://github.com/aspnet/SignalR/issues/1329) and they suggest me to get the result by sending it from the client to server to another method in the hub and so use TaskCompletionSource and some connection metadata to catch the result, but I'm stuck on how to do this
 
Controller Server :
 
[HttpPut("send/{message}")]
public async Task<IActionResult> SendMessage(string message)
{
    if (!ModelState.IsValid) return BadRequest(ModelState.Values);

    string connectionId = Request.Headers["connectionId"];
    await _chatHubContext.Clients.Client(connectionId).InvokeAsync("send");

    // Catch the call of MessageReceived and get the chat status

    return new OkObjectResult(new EmptyJsonResult() { Result = "OK" }); 

}
 
Hub Server
 
public class ChatHub : Hub
{
    public Task MessageReceive(bool chatStatus)
    {
        // Tell controller that message is received
    }
}
 
Angular 4 client
 
import { Component, Inject } from '@angular/core';
import { HubConnection } from '@aspnet/signalr-client';

@Component({
  selector: 'chat',
  templateUrl: './chat.component.html',
  styleUrls: ['./chat.component.css']
})
/** chat component*/
export class ChatComponent {
  hubConnection: HubConnection;
  chatStatus = false;

  /** chat ctor */
  constructor( @Inject('BASE_URL') private originUrl: string) {
    this.hubConnection = new HubConnection(`${this.originUrl}chat`);

    setInterval(() => {
      this.chatStatus = !this.chatStatus;
    },
      5000);

    this.hubConnection
      .start()
      .then(() => {
        this.hubConnection.on('send', (message: string) => {
          if (this.chatStatus) {
            //send message
          }
          this.hubConnection
            .invoke('messageReceived', this.chatStatus);
        });
      });

  }
}
 
As you can see on this code, I don't know what to do in the controller method and the Hub method to know that the method MessageReceive was called and to get his return to send it back to the controller request.

原文：https://stackoverflow.com/questions/48464800