How to make an angular module to ignore http interceptor added in a core module

user_4477818 0
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I do have a core module with an HttpInterceptor for authorization handling and I include this module in AppModule, in this way all the other modules that use HttpClient are using this interceptor.

@NgModule({
  imports: [],
  declarations: [],
  providers: [
    {
      provide: HTTP_INTERCEPTORS,
      useClass: AuthInterceptor,
      multi: true,
    },
  ]
})
export class CoreModule { }

How to make a module bypass the default interceptor?

@NgModule({
  imports: [
    CommonModule
  ],
  declarations: components,
  providers: [CustomService],
  exports: components,
})
export class ModuleWithoutInterceptorModule { }
angular-http-interceptors angular
3 Answers

In order to bypass all interceptors we can use HttpBackend as @deg suggested.

In other cases we can create HttpClient factory that will allows us to exclude interceptors from the interceptors chain:

import { createHttpClient } from './http-client.factory';
// ...

@Injectable({
  providedIn: 'root'
})
export class TodosApiService {
  http = createHttpClient(this.injector, [Interceptor2]);
//                                        ^^^^^^^^^^^^
//                                    Interceptors to exclude

  constructor(private injector: Injector) { }

  getTodo() {
    // Interceptor2 will be bypassed
    return this.http.get('https://jsonplaceholder.typicode.com/todos')
  }
}

Ng-run Example

Note that you can reuse this logic by creating base class:

@Injectable()
export class BasicHttpClient {
  protected http = createHttpClient(this.injector, [Interceptor2]);

  constructor(private injector: Injector) { }
}

@Injectable({ providedIn: 'root' })
export class TodosApiService extends BaseHttpClient {

  getTodo() {
    // Interceptor2 will be bypassed
    return this.http.get('https://jsonplaceholder.typicode.com/todos')
  }
}

http-client.factory.ts

import {
  HTTP_INTERCEPTORS,
  HttpBackend,
  HttpClient,
  HttpEvent,
  HttpHandler,
  HttpInterceptor,
  HttpRequest,
} from '@angular/common/http';
import { Observable } from 'rxjs';
import { Injector, Type } from '@angular/core';

class HttpInterceptorHandler implements HttpHandler {
  constructor(private next: HttpHandler, private interceptor: HttpInterceptor) {}

  handle(req: HttpRequest<any>): Observable<HttpEvent<any>> {
    return this.interceptor.intercept(req, this.next);
  } 
}

class HttpInterceptingHandler implements HttpHandler {
  private chain: HttpHandler | null = null;

  constructor(
    private backend: HttpBackend,
    private injector: Injector,
    private interceptorsToExclude: Type<HttpInterceptor>[],
    private intercept?: (req: HttpRequest<any>) => HttpRequest<any>
  ) {}

  handle(req: HttpRequest<any>): Observable<HttpEvent<any>> {
    if (this.intercept) {
      req = this.intercept(req);
    }

    if (this.chain === null) {
      const interceptors = this.injector
        .get(HTTP_INTERCEPTORS, [])
        .filter(
          interceptor => !this.interceptorsToExclude.some(interceptorType => interceptor instanceof interceptorType)
        );

      this.chain = interceptors.reduceRight(
        (next, interceptor) => new HttpInterceptorHandler(next, interceptor),
        this.backend
      );
    }
    return this.chain.handle(req);
  }
}

export function createHttpClient(
  injector: Injector,
  excludedInterceptors: Type<HttpInterceptor>[],
  intercept?: (req: HttpRequest<any>) => HttpRequest<any>
) {
  return new HttpClient(
    new HttpInterceptingHandler(injector.get(HttpBackend), injector, excludedInterceptors, intercept)
  );
}
user_54851670
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