如何在http错误的情况下保证可观察流的连续性？

Question

当我遇到 HTTP 错误响应时，以下方法 (onTrySignin) 出现问题。在我的 HTTP 调用之后的 catch 块阻止 Side Effect 抛出 Action 错误。如果我这样做 console.log 我会得到这个错误。

TypeError: You provided 'undefined' where a stream was expected. You can provide an Observable, Promise, Array, or Iterable.

如何保留 Observable 流并将响应传递到下一个块 (mergeMap)，我可以在其中触发其他 Actions、(FailedSignin())这种情况？

onTrySignin = this.actions$
    .ofType(AuthActions.TRY_SIGNIN)
    .map((action: AuthActions.TrySignin) => {
       return action.payload;
      })
    .switchMap((action: DispatchAction) => {
      const trySignInPayload: TrySignInPayload = action.payload;
      return this.httpService.postRequest('Account/Login', (trySignInPayload.loginData))
        .catch((error: any) => {
          console.log(error)
          return Observable.empty();
        })
        .mergeMap((response: HttpResponse<any>) => {
          switch (response.status) {
            case 200:
              if (trySignInPayload.returnUrl) {
                this.router.navigate([trySignInPayload.returnUrl]);
              } else {
                this.router.navigate(['/dbapp']);
              }
              return Observable.concat(
                Observable.of(new AuthActions.GenerateAntiforgeryToken()),
                Observable.of(new AuthActions.Signin(fromAuth.authId, this.fetchUserData()))
              );
              case 401:
              case 404:
              return Observable.concat(
                Observable.of(new AuthActions.FailedSignin()),
                Observable.empty()
              );
            default:
            return Observable.concat(
              Observable.of(new AuthActions.FailedSignin()),
              Observable.empty()
            );
          }
        })
    }).catch((error) => {
      return Observable.throw(error);
    });

这是我的httpService

public postRequest(apiUrl: string, jsonData: {} = {}): Observable<any> {
        return this.httpService.post(this.baseUrl + apiUrl, JSON.stringify(jsonData),
        {observe: 'response', reportProgress: true, withCredentials: true});
    }

Answer 1

您需要创建一个一次性流，我们是这样做的：

@Effect()
  login$: Observable<Action> = this.actions$
   .ofType(authActions.LOGIN)
   .switchMap((action: any) => {
     // @Effect stream is completing when the error occurs, preventing any further 
     // actions. Therefore create a disposable stream to keep @Effect stream alive
     return Observable.of(action)
       .switchMap((action: any) => {
         return this.apiService.login(action.payload);
       })
       .map((x: any) => {
         return new authActions.SetTokensAction({ token: x.data.token });
       })
       .catch((error: any) => {
         return Observable.of(new authActions.LoginFailedAction(error));
       });
    });

如何在http错误的情况下保证可观察流的连续性？

How to guarantee the continuity of observable stream in case of http errors?

observable

rxjs5

ngrx

ngrx-effects

angular