allow returning promise about ngx-config

[FritzHerbers]

@fulls1z3 I have the same or a similar problem.

Your HTTP interceptor will/might solve the problem when ConfigService is not yet initialized.
It does not solve the problem with a call to GetSettings (within mergeMap) with a resolved ConfigService as the HTTP request initiated by the ConfigHttpLoader has not yet returned data.

I have a service, in the constructor I receive an initialized ConfigService, but the call to GetSettings fails, as no config is yet available. (I think the OP has the same problem).

Is there a possibility to wait for the HTTP request to finish before calling getSettings or have getSettings to wait until the config is available ?

[fulls1z3]

@danielmhair first of all thanks for suggesting this feature, and I really appreciate each of them 😄

I think I more or less understood your case.

Actually, any of those ConfigLoaders are appended to APP_INITIALIZER lifecycle hook of the app, so in any of your services you should be able to access the configuration through the scalar method getSettings().

If the app is already initalized, then there're no problems.

However, there are some race conditions (ex: server-side rendering, injecting HTTP interceptors, etc.) where the app has not been initalized yet. For such cases I suggest you to pass an injector to the service and delay the invocation of getSettings method.

To make an example, and provide reference I'm hereby sharing a sample HTTP interceptor below:

// angular
import { Injectable, Injector } from '@angular/core';
import { HttpEvent, HttpHandler, HttpInterceptor, HttpRequest } from '@angular/common/http';

// libs
import { Observable } from 'rxjs';
import { mergeMap } from 'rxjs/operators';
import { get, getOr } from 'lodash/fp';
import { ConfigService } from '@ngx-config/core';
import { Auth0Service } from '@ngx-auth/auth0';

@Injectable()
export class JwtInterceptor implements HttpInterceptor {
  constructor(private readonly injector: Injector) {
  }

  intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    return Observable.create((observer: any) => {
      const item = this.injector.get(ConfigService);
      observer.next(item);
      observer.complete();
    })
      .pipe(
        mergeMap((res: ConfigService) => {
          const settings = res.getSettings('');
          const baseUrl = getOr('', 'backend.baseUrl', settings);

          if (get('auth', settings) && baseUrl && request.url.indexOf(baseUrl) >= 0) {
            const auth = this.injector.get(Auth0Service);

            if (auth && auth.accessToken)
              request = request.clone({
                setHeaders: {Authorization: `Bearer ${auth.accessToken}`}
              });
          }

          return next.handle(request);
        })
      );
  }
}

Don't forget to let me know about the results! 👍

[FritzHerbers]

Instead of ConfigHttpLoader i tried with ConfigStaticLoader.
The situation is the same, the Promise has not been resolved at the time the Service (used in an ngrx Effects) initializes.

[salem84]

I have the same problem... I cannot use angular-oauth2-oidc module initialization using JSON configurations.
Any news?

[djmcgrath101]

I managed to resolve this by using the loadSettings() method of the loader property in ConfigService which returns a Promise. Don't know what possible side effects this might have but it worked for me.

[unlight]

@fulls1z3
Is somebody working on this? Similar issues #147

[unlight]

As a stop gap solution CustomConfigHttpLoader

import { ConfigHttpLoader } from '@ngx-config/http-loader';
import pDefer from 'p-defer';

export class CustomConfigHttpLoader extends ConfigHttpLoader {
    readonly onLoadSettings = pDefer();

    async loadSettings(): Promise<void> {
        const result = await super.loadSettings();
        this.onLoadSettings.resolve();
        return result;
    }
}

in other app initializer

(configService.loader as CustomConfigHttpLoader).onLoadSettings.promise.then(() => {
console.log('loaded');
}));