angular - 检查 api 是否从 Angular 客户端应用程序关闭

Question

我有一个 Angular 8 应用程序，它从 .Net 代码 Web API 应用程序中提取数据。我需要检查 API 是否已关闭然后重定向到系统维护页面。我目前已经编写了一个方法，该方法将调用端点以查看服务是否可用并订阅该方法来检查每 10 秒。这是最好的方法吗

连接服务

@Injectable()
export class ConnectionService {
    constructor(private httpClient: HttpClient, private configurationService: ConfigurationService) { }
    checkIfCoreApiIsAvailable() {
        var pingUrl = this.configurationService.baseUrl + "/api/online";
        return this.httpClient.get(pingUrl);
    }
}

离线组件

@Component({
    selector: 'not-found',
    templateUrl: './offline.component.html',
    styleUrls: ['./offline.component.css'],
    animations: [fadeInOut]
})
export class OfflineComponent implements OnInit {
    subscription: Subscription;
    pingInterval: number;
    constructor(private connectionService: ConnectionService) {
        // Check if Core-API service is Online or Offline
        this.pingInterval = environment.corePingIntervalSeconds;
        const source = interval(this.pingInterval*1000);
        this.subscription = source.subscribe(val => 
            {
                this.opensnack();
                console.log(val);
            });   
    }

Answer 1

这种检查服务器可用性的方法完全没问题。您错过了对您的服务的调用。我认为这个重构会让你到达那里。 Here is a Stackblitz with working example ，我 ping 了谷歌，但你明白了:

      import { first } from "rxjs/operators";

      export class OfflineComponent implements OnInit {

        private source = interval(
           environment.corePingIntervalSeconds * 1000;
        );

        constructor(private connectionService: ConnectionService) {

          this.source.subscribe(() => {
             this.connectionService
            .checkIfCoreApiIsAvailable()
            .pipe(first())
            .subscribe(resp => {
              if (resp.status === 200 ) {
                console.log(true)
              } else {
                console.log(false)
              }
            }, err => console.log(err));
          });
        }
...