interceptor in angular 8

1import { Injectable } from '@angular/core';
2import { HttpInterceptor, HttpEvent, HttpResponse, HttpRequest, HttpHandler } from '@angular/common/http';
3import { Observable } from 'rxjs';
4
5@Injectable()
6export class MyInterceptor implements HttpInterceptor {
7  intercept(httpRequest: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
8    return next.handle(httpRequest);
9  }
10}
11

1// src/app/auth/auth.service.ts
2
3import { Injectable } from '@angular/core';
4import decode from 'jwt-decode';
5
6@Injectable()
7export class AuthService {  
8  public getToken(): string {
9    return localStorage.getItem('token');
10  }  
11
12	public isAuthenticated(): boolean {    
13      // get the token
14      const token = this.getToken();    
15      // return a boolean reflecting 
16      // whether or not the token is expired
17      return tokenNotExpired(null, token);  
18    }
19}
20
21// src/app/auth/token.interceptor.ts
22import { Injectable } from '@angular/core';
23import {
24  HttpRequest,
25  HttpHandler,
26  HttpEvent,
27  HttpInterceptor
28} from '@angular/common/http';
29import { AuthService } from './auth/auth.service';
30import { Observable } from 'rxjs/Observable';
31@Injectable()
32export class TokenInterceptor implements HttpInterceptor {
33  constructor(public auth: AuthService) {}
34  intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
35    
36    request = request.clone({
37      setHeaders: {
38        Authorization: `Bearer ${this.auth.getToken()}`
39      }
40    });
41    return next.handle(request);
42  }
43}
44
45// src/app/app.module.ts
46import { HTTP_INTERCEPTORS } from '@angular/common/http';
47import { TokenInterceptor } from './../auth/token.interceptor';
48
49@NgModule({  bootstrap: [AppComponent],
50          	 imports: [...],
51			 providers: [
52                       { 
53                       provide: HTTP_INTERCEPTORS,
54                       useClass: TokenInterceptor,
55                       multi: true   
56                       }  
57          ]})
58export class AppModule {}

1// src/app/app.module.ts
2
3import { HTTP_INTERCEPTORS } from '@angular/common/http';
4import { TokenInterceptor } from './../auth/token.interceptor';
5
6@NgModule({
7  bootstrap: [AppComponent],
8  imports: [...],
9  providers: [
10    {
11      provide: HTTP_INTERCEPTORS,
12      useClass: TokenInterceptor,
13      multi: true
14    }
15  ]
16})
17export class AppModule {}
18

1      
2      interface HttpInterceptor {
3  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>>
4}
5    

1// register the interceptor as a service
2$provide.factory('myHttpInterceptor', function($q, dependency1, dependency2) {
3  return {
4    // optional method
5    'request': function(config) {
6      // do something on success
7      return config;
8    },
9
10    // optional method
11   'requestError': function(rejection) {
12      // do something on error
13      if (canRecover(rejection)) {
14        return responseOrNewPromise
15      }
16      return $q.reject(rejection);
17    },
18
19
20
21    // optional method
22    'response': function(response) {
23      // do something on success
24      return response;
25    },
26
27    // optional method
28   'responseError': function(rejection) {
29      // do something on error
30      if (canRecover(rejection)) {
31        return responseOrNewPromise
32      }
33      return $q.reject(rejection);
34    }
35  };
36});
37
38$httpProvider.interceptors.push('myHttpInterceptor');
39
40
41// alternatively, register the interceptor via an anonymous factory
42$httpProvider.interceptors.push(function($q, dependency1, dependency2) {
43  return {
44   'request': function(config) {
45       // same as above
46    },
47
48    'response': function(response) {
49       // same as above
50    }
51  };
52});