Question

当我将响应json从websocket服务器转换为ts对象时，我有一个基本问题，但我找不到错误在哪里... 你能帮忙解决一下吗？

这是websocket服务器：

const wsServer: Server = new Server({port: WEBSOCKET_PORT});

console.log('WebSocket server is listening on port 8085');
export class PushData {
  constructor(public push: string,
              public workflowId: number) {
  }
}

wsServer.on('connection', (websocket, req) => {
  websocket.send('This message was pushed by WebSocket server');
  websocket.send('Data pushed by server: ');
  websocket.on('message', (message) => {
    console.log('Server received : %s', message);
    const todaysDate = new Date();
    // websocket.send('Data pushed by server: ' + todaysDate.toString());
    const request1 = new PushData('data', 30);
    websocket.send(JSON.stringify(request1));
   }
}

这是客户班级服务：

private faceSubject = new BehaviorSubject<any>(null);
createObservableSocket(url: string): Observable<string> {
  this.ws = new WebSocket(url);
  return new Observable(
    observer => {
      this.ws.onmessage = (event) => observer.next(event.data);
      this.ws.onerror = (event) => observer.error(event);
      this.ws.onclose = (event) => observer.complete();
    }
  );
}

这里是客户端组件，我想进行转换：

ngAfterViewInit(): void {
  this.drawOverlayPicture();

  // subscribe to the subject
  this.subscription = this.wsService.getFaceSubject()
    .subscribe((data: PushData) => {
        if (data !== null) {
          console.log('received data from server', data);
          console.log('received data from server push=', data.push);
          // var ob = JSON.parse(JSON.stringify(data));
          // console.log('received data from server, workflowId=', (<PushData> ob).push);
          console.log(this.i++);
}

和

export class PushData {
  constructor(public push: string, public workflowId: number) {}
}

这里我总是te data.push = undefined。你能告诉我如何将websocket响应转换为对象吗？

Answer 1

编辑： 服务器只在从客户端收到消息时才会推送PushData对象，但是他会在连接时向客户端发送两个字符串。这就是为什么你得到data.push是未定义的，因为数据只是字符串。

websocket.send('This message was pushed by WebSocket server');  
websocket.send('Data pushed by server: ');

您需要从客户端发出消息才能接收pushData对象！

Typescript将字符串转换为对象错误

1 个答案: