Authorization in Angular UI

OAuth is preconfigured in Angular application templates. So, when you start a project using the CLI (or Suite, for that matter), authorization already works. ABP Angular UI packages are using angular-oauth2-oidc library for managing OAuth in the Angular client. You can find OAuth configuration in the environment.ts files.

Authorization Code Flow

import { Config } from '@abp/ng.core';

const baseUrl = 'http://localhost:4200';

export const environment = {
  // other options removed for sake of brevity

  oAuthConfig: {
    issuer: 'https://localhost:44305',
    redirectUri: baseUrl,
    clientId: 'MyProjectName_App',
    responseType: 'code',
    scope: 'offline_access MyProjectName',

  // other options removed for sake of brevity
} as Config.Environment;

This configuration results in an OAuth authorization code flow with PKCE. According to this flow, the user is redirected to an external login page which is built with MVC. So, if you need to customize the login page, please follow this community article.

Resource Owner Password Flow

If you have used the Angular UI account module in your project, you can switch to the resource owner password flow by changing the OAuth configuration in the environment.ts files as shown below:

import { Config } from '@abp/ng.core';

export const environment = {
  // other options removed for sake of brevity

  oAuthConfig: {
    issuer: 'https://localhost:44305',
    clientId: 'MyProjectName_App',
    dummyClientSecret: '1q2w3e*',
    scope: 'offline_access MyProjectName',

  // other options removed for sake of brevity
} as Config.Environment;

According to this flow, the user is redirected to the login page in the account module.

Error Filtering

In AuthFlowStrategy class, there is a method called listenToOauthErrors that listens to OAuthErrorEvent errors. This method clears the localStorage for OAuth keys. However, in certain cases, we might want to skip this process. To achieve this, we can use the AuthErrorFilterService. The AuthErrorFilterService is an abstract service that needs to be replaced with a custom implementation

By default, this service is replaced in the @abp/ng.oauth package


1.Create an auth-filter.provider

import { APP_INITIALIZER, inject } from '@angular/core';
import { AuthErrorFilter, AuthErrorEvent, AuthErrorFilterService } from '@abp/ng.core';
import { eCustomersAuthFilterNames } from '../enums';

  { provide: APP_INITIALIZER, useFactory: configureAuthFilter, multi: true },

type Reason = object & { error: { grant_type: string | undefined } };

function configureAuthFilter() {
  const errorFilterService = inject(
    AuthErrorFilterService<AuthErrorFilter<AuthErrorEvent>, AuthErrorEvent>,
  const filter: AuthErrorFilter = {
    id: eCustomersAuthFilterNames.LinkedUser,
    executable: true,
    execute: (event: AuthErrorEvent) => {
      const { reason } = event;
      const {
        error: { grant_type },
      } = <Reason>(reason || {});

      return !!grant_type && grant_type === eCustomersAuthFilterNames.LinkedUser;

  return () => errorFilterService.add(filter);
  • AuthErrorFilter: is a model for filter object and it have 3 properties
    • id: a unique key in the list for the filter object
    • executable: a status for the filter object. If it's false then it won't work, yet it'll stay in the list
    • execute: a function that stores the skip logic

2.Add to the FeatureConfigModule

import { ModuleWithProviders, NgModule } from "@angular/core";
import { CUSTOMERS_AUTH_FILTER_PROVIDER } from "./providers/auth-filter.provider";

export class CustomersConfigModule {
  static forRoot(): ModuleWithProviders<CustomersConfigModule> {
    return {
      ngModule: CustomersConfigModule,

Now it'll skip the clearing of OAuth storage keys for LinkedUser grant_type if any OAuthErrorEvent occurs

Replace with custom implementation

Use the AbstractAuthErrorFilter<T,E> class for signs of process.



import { Injectable, signal } from '@angular/core';
import { MyAuthErrorEvent } from 'angular-my-auth-oidc';
import { AbstractAuthErrorFilter, AuthErrorFilter } from '@abp/ng.core';

@Injectable({ providedIn: 'root' })
export class OAuthErrorFilterService extends AbstractAuthErrorFilter<
> {
  protected readonly _filters = signal<Array<AuthErrorFilter<MyAuthErrorEvent>>>([]);
  readonly filters = this._filters.asReadonly();

  get(id: string): AuthErrorFilter<MyAuthErrorEvent> {
    return this._filters().find(({ id: _id }) => _id === id);

  add(filter: AuthErrorFilter<MyAuthErrorEvent>): void {
    this._filters.update(items => [...items, filter]);

  patch(item: Partial<AuthErrorFilter<MyAuthErrorEvent>>): void {
    const _item = this.filters().find(({ id }) => id ===;
    if (!_item) {

    Object.assign(_item, item);

  remove(id: string): void {
    const item = this.filters().find(({ id: _id }) => _id === id);
    if (!item) {

    this._filters.update(items => items.filter(({ id: _id }) => _id !== id));

  run(event: MyAuthErrorEvent): boolean {
    return this.filters()
      .filter(({ executable }) => !!executable)
      .map(({ execute }) => execute(event))
      .some(item => item);

See Also

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