Angular 7/8/9/10 HttpClient & Http Services Tutorial Last updated on August 4, 2020 by Digamber

consume RESTful API in Angular 8/9/10 using HttpClient service. HttpClient service is a very useful API in Angular to communicate with the remote server. HttpClient API Features Observable Support

Hassle Free API Testing

Smooth Requests & Response Mechanism

Better Error Handling Hello folks, today I am going to show you how you can. HttpClient service is a very useful API in Angular to communicate with the remote server. HttpClient is an injectable service, it comes with the various powerful methods to communicate with the remote server. HttpClient API can send Http POST, GET, PUT and DELETE requests easily. HttpClient service methods in Angular 7 request()

delete()

get()

head()

jsonp()

options()

patch()

post()

put() I’ll be showing you the practical examples of standard HTTP methods like GET, PUT, POST and DELETE, these methods allow you to communicate with a REST API server. By the end of this tutorial, you’ll be able to understand… How to set up the HttpClientModule in Angular 7/8 app?

How to make a request using a local server with JSON server NPM package.

How to make GET, POST, PUT & DELETE request with Angular 7/8 using HttpClient API

1. Prerequisite – Setup Node JS development environment In order to create this demo app you must have Node JS development environment set up in your machine. Please follow this link How to Set up Node JS Development Environment?

2. Install Angular CLI Angular projects are developed using Angular CLI, it’s an official tool. Hit the given below command to install the Angular CLI, ignore if Angular CLI is already installed. npm install @angular/cli -g

3. How to set up Angular 7 Project using Angular CLI from scratch? I will be creating an employee record management system with Angular 7, in this demo app i will consume RESTful API via HttpClient service. It’s time to setup Angular 7 project, run the following command in Angular CLI. ng new angular-httpclient-app It will ask you the following questions… Would you like to add Angular routing?

Select y and Hit Enter. Which stylesheet format would you like to use? (Use arrow keys)

Choose CSS and hit Enter After that your project will start creating, Once the project is created then don’t forget to get into the project’s folder. cd angular-httpclient-app I’ll be using Bootstrap 4 CSS framework with Angular 7 for consuming RESTful API with HttpClient service. Hit the following command to get the Bootstrap in your Angular app. npm install bootstrap After that, Go to angular.json file and replace the given below code with “styles”: [ ] array. "styles" : [ "node_modules/bootstrap/dist/css/bootstrap.min.css" , "src/styles.css" ] Start your project using given below command. ng serve --open Generate components for Angualr 7 Demo App ng g c employee-create ng g c employee-edit ng g c employee-list

4. Configure JSON Server in Angular 8/9/10 We are going to create a fake server for testing our Angular 7 app, so we will be taking help of json-server NPM package to sort out our problem. Install JSON server in our project, run the following command in Angular CLI. npm i json-server --save Then, create a folder by the name of server and keep your database file in it to manage the APIs locally. mkdir server && cd server touch server/db.json Once the db.json file is created then add some data in it. { "employees" : [ { "id" : 1 , "name" : "Tony Stark" , "email" : "tony@mcu.com" , "phone" : "001-123-4567" } , { "id" : 2 , "name" : "Black Widow" , "email" : "black-widow@mcu.com" , "phone" : "001-123-4568" } ] } After that run the following command to run the JSON server. json-server --watch server/db.json Now if you make any request with Angualr 7 Http post, put, get or delete your db.json file will get updated locally. You can check your local db.json file on this URL http://localhost:3000/employees .

5. Enable Routing Service in Angular 8/9/10 For navigating between components in Angular we need to activate routing service in our application, to enable routes go to app-routing.module.ts file and add the following code. import { NgModule } from '@angular/core' ; import { Routes , RouterModule } from '@angular/router' ; import { EmployeeCreateComponent } from './employee-create/employee-create.component' ; import { EmployeeEditComponent } from './employee-edit/employee-edit.component' ; import { EmployeesListComponent } from './employees-list/employees-list.component' ; const routes : Routes = [ { path : '' , pathMatch : 'full' , redirectTo : 'create-employee' } , { path : 'create-employee' , component : EmployeeCreateComponent } , { path : 'employees-list' , component : EmployeesListComponent } , { path : 'employee-edit/:id' , component : EmployeeEditComponent } ] ; @ NgModule ( { imports : [ RouterModule . forRoot ( routes ) ] , exports : [ RouterModule ] } ) export class AppRoutingModule { }

6. How to Set up HttpClient API in Angular 8/9/10 App for Consuming RESTful API? In this tutorial, I will give you the demo to access the external server to fetch the data using the RESTful API in Angular 6 | 7 with HttpClient service. In order to use HttpClient API to make the communication with Http remote server, you must set up this service in your Angular app. Go to app.module.ts and paste the following code. import { HttpClientModule } from '@angular/common/http' ; Include the HttpClientModule in @NgModule's imports array. @ NgModule ( { imports : [ HttpClientModule ] } ) You’ve injected the HttpClientModule in your application, now you can use it easily in your Angular 7 application.

7. How to Create Angular Service for consuming RESTful API using Angular 7 HttpClient Service? In order to create consume RESTful API using Angualr 7 HttpClient service we need to create a service file in our app. This file will hold the core logic of our demo application. Functionalites to be covered: Create Employee

Delete Employee

Update Employee

Manage Employee List In order to create CRUD operations using RESTful API in Angular, we need to generate employee.ts class and rest-api.service.ts files. Generate Employee Interface Class ng g cl shared/Employee Go to shared/employee.ts and define data types within the Employee class. export class Employee { id : string ; name : string ; email : string ; phone : number ; } Generate RestApiService Class ng g s shared/rest-api I will be writing down core logic in this file for consuming RESTful API using HttpClient API. We will also use RxJS to handle asynchronous operations and errors in this demo app. Let’s go to shared/rest-api.service.ts file and add the following code. import { Injectable } from '@angular/core' ; import { HttpClient , HttpHeaders } from '@angular/common/http' ; import { Employee } from '../shared/employee' ; import { Observable , throwError } from 'rxjs' ; import { retry , catchError } from 'rxjs/operators' ; @ Injectable ( { providedIn : 'root' } ) export class RestApiService { apiURL = 'http://localhost:3000' ; constructor ( private http : HttpClient ) { } httpOptions = { headers : new HttpHeaders ( { 'Content-Type' : 'application/json' } ) } getEmployees ( ) : Observable < Employee > { return this . http . get < Employee > ( this . apiURL + '/employees' ) . pipe ( retry ( 1 ) , catchError ( this . handleError ) ) } getEmployee ( id ) : Observable < Employee > { return this . http . get < Employee > ( this . apiURL + '/employees/' + id ) . pipe ( retry ( 1 ) , catchError ( this . handleError ) ) } createEmployee ( employee ) : Observable < Employee > { return this . http . post < Employee > ( this . apiURL + '/employees' , JSON . stringify ( employee ) , this . httpOptions ) . pipe ( retry ( 1 ) , catchError ( this . handleError ) ) } updateEmployee ( id , employee ) : Observable < Employee > { return this . http . put < Employee > ( this . apiURL + '/employees/' + id , JSON . stringify ( employee ) , this . httpOptions ) . pipe ( retry ( 1 ) , catchError ( this . handleError ) ) } deleteEmployee ( id ) { return this . http . delete < Employee > ( this . apiURL + '/employees/' + id , this . httpOptions ) . pipe ( retry ( 1 ) , catchError ( this . handleError ) ) } handleError ( error ) { let errorMessage = '' ; if ( error . error instanceof ErrorEvent ) { errorMessage = error . error . message ; } else { errorMessage = `Error Code: ${ error . status }

Message: ${ error . message } ` ; } window . alert ( errorMessage ) ; return throwError ( errorMessage ) ; } }

8. Access HttpClient API from Angular Component We’ve successfully created RESTful services using Angular 8/9/10 HttpClient API, its time to access rest-api.service.ts via Angular 7 components. Go to your app.module.ts file and add the following code, this file holds the core services to run our demo app. import { BrowserModule } from '@angular/platform-browser' ; import { NgModule } from '@angular/core' ; import { AppComponent } from './app.component' ; import { HttpClientModule } from '@angular/common/http' ; import { AppRoutingModule } from './app-routing.module' ; import { FormsModule } from '@angular/forms' ; import { EmployeeCreateComponent } from './employee-create/employee-create.component' ; import { EmployeeEditComponent } from './employee-edit/employee-edit.component' ; import { EmployeesListComponent } from './employees-list/employees-list.component' ; @ NgModule ( { declarations : [ AppComponent , EmployeeCreateComponent , EmployeeEditComponent , EmployeesListComponent ] , imports : [ BrowserModule , AppRoutingModule , HttpClientModule , FormsModule ] , providers : [ ] , bootstrap : [ AppComponent ] } ) export class AppModule { } Create an Employee by Making an HTTP POST Request in Angular 7 Go to employee-create.component.html add the following code. < div class = " container custom-container " > < div class = " col-md-12 " > < h3 class = " mb-3 text-center " > Create Employee </ h3 > < div class = " form-group " > < input type = " text " [(ngModel)] = " employeeDetails.name " class = " form-control " placeholder = " Name " > </ div > < div class = " form-group " > < input type = " text " [(ngModel)] = " employeeDetails.email " class = " form-control " placeholder = " Email " > </ div > < div class = " form-group " > < input type = " text " [(ngModel)] = " employeeDetails.phone " class = " form-control " placeholder = " Phone " > </ div > < div class = " form-group " > < button class = " btn btn-success btn-lg btn-block " (click) = " addEmployee() " > Create Employee </ button > </ div > </ div > </ div > Go to employee-create.component.ts file and add the following code. import { Component , OnInit , Input } from '@angular/core' ; import { Router } from '@angular/router' ; import { RestApiService } from "../shared/rest-api.service" ; @ Component ( { selector : 'app-employee-create' , templateUrl : './employee-create.component.html' , styleUrls : [ './employee-create.component.css' ] } ) export class EmployeeCreateComponent implements OnInit { @ Input ( ) employeeDetails = { name : '' , email : '' , phone : 0 } constructor ( public restApi : RestApiService , public router : Router ) { } ngOnInit ( ) { } addEmployee ( dataEmployee ) { this . restApi . createEmployee ( this . employeeDetails ) . subscribe ( ( data : { } ) => { this . router . navigate ( [ '/employees-list' ] ) } ) } } By adding given above code in employee create component, we can easily create an employee by making an HTTP POST request via Angular 7 component.

9. Send HTTP GET and DELETE Requests in Angular 7/8/9/10 to Manage Employees List In this section i am going to manage employees list which we have created above. I will be using our RESTful API service by sending get() and delete() request via our custom apis. employees-list.component.html < div class = " container custom-container-2 " > < div class = " no-data text-center " *ngIf = " Employee.length == 0 " > < p > There is no employee added yet! </ p > < button class = " btn btn-outline-primary " routerLink = " /create-employee " > Add Empoyee </ button > </ div > < div *ngIf = " Employee.length !== 0 " > < h3 class = " mb-3 text-center " > Employees List </ h3 > < div class = " col-md-12 " > < table class = " table table-bordered " > < thead > < tr > < th scope = " col " > User Id </ th > < th scope = " col " > Name </ th > < th scope = " col " > Email </ th > < th scope = " col " > Phone </ th > < th scope = " col " > Action </ th > </ tr > </ thead > < tbody > < tr *ngFor = " let employee of Employee " > < td > {{employee.id}} </ td > < td > {{employee.name}} </ td > < td > {{employee.email}} </ td > < td > {{employee.phone}} </ td > < td > < span class = " edit " routerLink = " /employee-edit/{{employee.id}} " > Edit </ span > < span class = " delete " (click) = " deleteEmployee(employee.id) " > Delete </ span > </ td > </ tr > </ tbody > </ table > </ div > </ div > </ div > employees-list.component.ts import { Component , OnInit } from '@angular/core' ; import { RestApiService } from "../shared/rest-api.service" ; @ Component ( { selector : 'app-employees-list' , templateUrl : './employees-list.component.html' , styleUrls : [ './employees-list.component.css' ] } ) export class EmployeesListComponent implements OnInit { Employee : any = [ ] ; constructor ( public restApi : RestApiService ) { } ngOnInit ( ) { this . loadEmployees ( ) } loadEmployees ( ) { return this . restApi . getEmployees ( ) . subscribe ( ( data : { } ) => { this . Employee = data ; } ) } deleteEmployee ( id ) { if ( window . confirm ( 'Are you sure, you want to delete?' ) ) { this . restApi . deleteEmployee ( id ) . subscribe ( data => { this . loadEmployees ( ) } ) } } }

10. Make HTTP PUT Request in Angular to Update Data I am going to send HTTP PUT Request in Angular to update current employee data in our little demo app, It’s pretty simple just follow the following steps. employee-edit.component.html < div class = " container custom-container " > < div class = " col-md-12 " > < h3 class = " mb-3 text-center " > Update Employee </ h3 > < div class = " form-group " > < input type = " text " [(ngModel)] = " employeeData.name " class = " form-control " placeholder = " Name " > </ div > < div class = " form-group " > < input type = " text " [(ngModel)] = " employeeData.email " class = " form-control " placeholder = " Email " > </ div > < div class = " form-group " > < input type = " text " [(ngModel)] = " employeeData.phone " class = " form-control " placeholder = " Phone " > </ div > < div class = " form-group " > < button class = " btn btn-success btn-lg btn-block " (click) = " updateEmployee() " > Update Employee </ button > </ div > </ div > </ div > employee-edit.component.ts import { Component , OnInit } from '@angular/core' ; import { RestApiService } from "../shared/rest-api.service" ; import { ActivatedRoute , Router } from '@angular/router' ; @ Component ( { selector : 'app-employee-details' , templateUrl : './employee-edit.component.html' , styleUrls : [ './employee-edit.component.css' ] } ) export class EmployeeEditComponent implements OnInit { id = this . actRoute . snapshot . params [ 'id' ] ; employeeData : any = { } ; constructor ( public restApi : RestApiService , public actRoute : ActivatedRoute , public router : Router ) { } ngOnInit ( ) { this . restApi . getEmployee ( this . id ) . subscribe ( ( data : { } ) => { this . employeeData = data ; } ) } updateEmployee ( ) { if ( window . confirm ( 'Are you sure, you want to update?' ) ) { this . restApi . updateEmployee ( this . id , this . employeeData ) . subscribe ( data => { this . router . navigate ( [ '/employees-list' ] ) } ) } } } Now you can test your Angular 7/8/9/10 HttpClient application in the browser, just type ng serve in the terminal.

11. GitHub Project Files GitHub Resources