Angular HTTP API | FULL COURSE

If you want to build powerful web applications, you need to have a solid understanding of how to work with APIs in Angular. In this full course, we will cover everything you need to know about Angular’s HTTP API.

Introduction to Angular HTTP API

The Angular HTTP API allows you to make HTTP requests to retrieve data from a server or send data to a server. It simplifies the process of working with APIs and provides a set of powerful features to handle common use cases.

Setting Up Angular HTTP

Before we can start using Angular’s HTTP API, we need to set up our Angular project. If you haven’t already, make sure you have Angular CLI installed on your machine. Then, create a new Angular project by running the following command in your terminal:

ng new my-app

Once the project is set up, navigate to the project directory by running:

cd my-app

Next, we need to import the HttpClientModule into our project. Open the src/app/app.module.ts file and add the following line:

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

Then, add the HttpClientModule to the imports array in the NgModule decorator:

imports: [HttpClientModule]

With these steps completed, we are ready to start using Angular’s HTTP API.

Making GET Requests

One common use case for APIs is fetching data from a server. In Angular, we can use the HttpClient service to make GET requests. Here’s an example:

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

getData() {
return this.http.get('https://api.example.com/data');
}

In this example, we import the HttpClient service and inject it into our component. Then, we define a function called getData that makes a GET request to https://api.example.com/data. The http.get method returns an observable that we can subscribe to in order to handle the response.

Handling POST Requests

In addition to making GET requests, we can also use Angular’s HTTP API to make POST requests. Here’s an example:

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

postData(data: any) {
return this.http.post('https://api.example.com/data', data);
}

In this example, we define a function called postData that takes in some data as a parameter. The http.post method sends a POST request to https://api.example.com/data with the specified data. Like with GET requests, the http.post method returns an observable that we can subscribe to.

Handling HTTP Interceptors

Angular’s HTTP API also provides a way to intercept and modify HTTP requests and responses using HTTP interceptors. This is useful for adding headers, logging, or handling errors globally across your application. Here’s how to set up an HTTP interceptor:

import { Injectable } from '@angular/core';
import { HttpInterceptor, HttpRequest, HttpHandler, HttpEvent } from '@angular/common/http';
import { Observable } from 'rxjs';

return next.handle(modifiedRequest);
}
}

In this example, we define a class called MyInterceptor that implements the HttpInterceptor interface. The intercept method is called for each HTTP request, allowing us to modify the request or add headers. We then create a modified request using the request.clone method and pass it to next.handle to continue the request chaining process.

Conclusion

In this full course, we have covered everything you need to know about Angular’s HTTP API. From setting up Angular to making GET and POST requests, as well as handling HTTP interceptors, you now have the knowledge and skills to work with APIs in Angular effectively. Happy coding!