Skip to main content

3 Best Ways To Set Http Request Header in Angular 4 and Angular 2!

How to Set Http Request Header in Angular 4 and Angular 2?
The HTTP Interceptors are used to Set Http Headers Request in Angular 4 using the import from “@angular/common/http”. The HTTP Interceptors are available in Angular 4.x versions.

The HTTP Interceptors are not supported in Angular 2. We are creating the HttpClient Injectable class to achieve this. You can see the below examples for set http headers request with and without HTTP interceptors.

What Is the Use of Interceptors in Angular 4?
The Interceptors is a common used to set default headers for all responses.

Example 1 –  For Angular 4

Set Headers Http Request Using Http Interceptors -
The HTTP Interceptors are now available via using the new HttpClient from angular/common/http in the Angular 4.x versions.

Steps 1 - Writing an interceptor for adds a header for every request!
import {HttpEvent, HttpInterceptor, HttpHandler, HttpRequest} from '@angular/common/http';

export class AddHttpHeaderInterceptor implements HttpInterceptor {
  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    // Get the auth header from the service.
    const authHeader = 'token_value';
    const clonedReq = req.clone({headers: req.headers.set('Authorization', authHeader)});

    return next.handle(clonedReq);
  }
}

Steps 2 - Providing your interceptor!
- After creating the interceptor, we need to register it using the HTTP_INTERCEPTORS in the @NgModule()

import { HTTP_INTERCEPTORS } from '@angular/common/http';

@NgModule({
  providers: [{
    provide: HTTP_INTERCEPTORS,
    useClass: AddHttpHeaderInterceptor,
    multi: true,
  }],
})

export class AppModule {}

Example 2-  For Angular 2

Set Headers Http Request without HTTP Interceptors  -

Steps 1 – We are creating the HttpClient Injectable class.
import {Injectable} from '@angular/core';
import {Http, Headers} from '@angular/http';

@Injectable()
export class HttpClient {
  constructor(private http: Http) {}

  createAuthHeader(headers: Headers) {
    headers.append('Content-Type', 'application/json');
    headers.append('Authorization', 'Basic ' + btoa('user-name:password')); 
  }

  get(url) {
    let headers = new Headers();
    this.createAuthHeader(headers);

    return this.http.get(url, {headers: headers});
  }

  post(url, data) {
    let headers = new Headers();
    this.createAuthHeader(headers);

    return this.http.post(url, data, {headers: headers});
  }

  put(url, data) {
    let headers = new Headers();
    this.createAuthHeader(headers);

    return this.http.put(url, data, {headers: headers});
  }
}

Steps 2 - Injecting the HttpClient object in the Component
import { HttpClient } from '../http-client';

export class userComponent {
  constructor(http: HttpClient) {
    this.http = httpClient;
  }

  getUsers() {
    this.http.get(url).subscribe(data =>{console.log(data); });
  }

  addUsers(user) {
    this.http.post(url, user).subscribe(data =>{console.log(data); });
  }
}

References –

I hope you are enjoying with this post! Please share with you friends! Thank you!!!
By Anil Singh | Rating of this article (*****)

Popular posts from this blog

Angular 2, 4, 5, 6, 7, 8 and 9 Interview Questions and Answers -Books

» Are you preparing for Angular Interview? Buy this book (Including Angular 8, 7, 6, 5,4, 2) Interview Q/A Interview Q/A Interview Q/A Interview Q/A Interview Q/A Interview Q/A Interview Q/A » A Complete Guide Book of Angular 9 This is a concise, complete overview of the key aspects of Angular 9. It is fully up to date with the latest release of Angular. This article provide all the important aspects required for angular developers looking for brief and useful content... Posted In Angular 9 » A Complete Guide Book of Angular 8 This is a concise, complete overview of the key aspects of Angular 9. It is fully up to date with the latest release of Angular. This article provide all the important aspects required for angular developers looking for brief and useful content... Posted In Angular 8 » A Complete Guide Book of Angular 7 This is a concise, complete overview of the key aspects of Angular 7. It is fully up to date with the latest release of Angular. This

39 Best Object Oriented JavaScript Interview Questions and Answers

Most Popular 37 Key Questions for JavaScript Interviews. What is Object in JavaScript? What is the Prototype object in JavaScript and how it is used? What is "this"? What is its value? Explain why "self" is needed instead of "this". What is a Closure and why are they so useful to us? Explain how to write class methods vs. instance methods. Can you explain the difference between == and ===? Can you explain the difference between call and apply? Explain why Asynchronous code is important in JavaScript? Can you please tell me a story about JavaScript performance problems? Tell me your JavaScript Naming Convention? How do you define a class and its constructor? What is Hoisted in JavaScript? What is function overloadin

25 Best Vue.js 2 Interview Questions and Answers

What Is Vue.js? The Vue.js is a progressive JavaScript framework and used to building the interactive user interfaces and also it’s focused on the view layer only (front end). The Vue.js is easy to integrate with other libraries and others existing projects. Vue.js is very popular for Single Page Applications developments. The Vue.js is lighter, smaller in size and so faster. It also supports the MVVM ( Model-View-ViewModel ) pattern. The Vue.js is supporting to multiple Components and libraries like - ü   Tables and data grids ü   Notifications ü   Loader ü   Calendar ü   Display time, date and age ü   Progress Bar ü   Tooltip ü   Overlay ü   Icons ü   Menu ü   Charts ü   Map ü   Pdf viewer ü   And so on The Vue.js was developed by “ Evan You ”, an Ex Google software engineer. The latest version is Vue.js 2. The Vue.js 2 is very similar to Angular because Evan You was inspired by Angular and the Vue.js 2 components looks like -

nullinjectorerror no provider for httpclient angular 17

In Angular 17 where the standalone true option is set by default, the app.config.ts file is generated in src/app/ and provideHttpClient(). We can be added to the list of providers in app.config.ts Step 1:   To provide HttpClient in a standalone app we could do this in the app.config.ts file, app.config.ts: import { ApplicationConfig } from '@angular/core'; import { provideRouter } from '@angular/router'; import { routes } from './app.routes'; import { provideClientHydration } from '@angular/platform-browser'; //This (provideHttpClient) will help us to resolve the issue  import {provideHttpClient} from '@angular/common/http'; export const appConfig: ApplicationConfig = {   providers: [ provideRouter(routes),  provideClientHydration(), provideHttpClient ()      ] }; The appConfig const is used in the main.ts file, see the code, main.ts : import { bootstrapApplication } from '@angular/platform-browser'; import { appConfig } from '

List of Countries, Nationalities and their Code In Excel File

Download JSON file for this List - Click on JSON file    Countries List, Nationalities and Code Excel ID Country Country Code Nationality Person 1 UNITED KINGDOM GB British a Briton 2 ARGENTINA AR Argentinian an Argentinian 3 AUSTRALIA AU Australian an Australian 4 BAHAMAS BS Bahamian a Bahamian 5 BELGIUM BE Belgian a Belgian 6 BRAZIL BR Brazilian a Brazilian 7 CANADA CA Canadian a Canadian 8 CHINA CN Chinese a Chinese 9 COLOMBIA CO Colombian a Colombian 10 CUBA CU Cuban a Cuban 11 DOMINICAN REPUBLIC DO Dominican a Dominican 12 ECUADOR EC Ecuadorean an Ecuadorean 13 EL SALVADOR