Angular 8/9 HttpClient & Http Tutorial - Build, Consume RESTful API

Angular 8/9 HttpClient & Http tutorial is going to be discussed in this blog today. We’ll learn to create and consume RESTful APIs in Angular project. To manage the data on the remote server, we make GET, POST, PUT and Delete using HttpClient API. We are required to import and setup HttpClient service in Angular project to consume REST APIs.
To work with HttpClient service in Angular, you need to import the HttpClientModule in app.module.ts file. Then inject HttpClient service in constructor method after that you can hit the remote server via HTTP’s POST, GET, PUT and DELETE methods.

HttpClient in Angular 8/9

HttpClient API service is used to make communication between front-end web apps with backend services. This communication is done over HTTP protocol. Angular 8/9 HttpClient service makes the communication with remote server very easy. It needs to be imported via @angular/common/http package.

Benefits of HttpClient Service

Easy Testing
Typed Request & Response Objects
Request Interception
Response Interception
APIs Observable Support
Easy Error Handling

What Does `Angular.io` say About HttpClient?

“HttpClient is available as an injectable class, with methods to perform HTTP requests. Each request method has multiple signatures, and the return type varies based on the signature that is called (mainly the values of observe and responseType).”

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Angular 8/9 HttpClient & Http Tutorial - Build, Consume RESTful API

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What is REST API? An Overview | Liquid Web

What is REST?

The REST acronym is defined as a “REpresentational State Transfer” and is designed to take advantage of existing HTTP protocols when used for Web APIs. It is very flexible in that it is not tied to resources or methods and has the ability to handle different calls and data formats. Because REST API is not constrained to an XML format like SOAP, it can return multiple other formats depending on what is needed. If a service adheres to this style, it is considered a “RESTful” application. REST allows components to access and manage functions within another application.

REST was initially defined in a dissertation by Roy Fielding’s twenty years ago. He proposed these standards as an alternative to SOAP (The Simple Object Access Protocol is a simple standard for accessing objects and exchanging structured messages within a distributed computing environment). REST (or RESTful) defines the general rules used to regulate the interactions between web apps utilizing the HTTP protocol for CRUD (create, retrieve, update, delete) operations.

What is an API?

An API (or Application Programming Interface) provides a method of interaction between two systems.

What is a RESTful API?

A RESTful API (or application program interface) uses HTTP requests to GET, PUT, POST, and DELETE data following the REST standards. This allows two pieces of software to communicate with each other. In essence, REST API is a set of remote calls using standard methods to return data in a specific format.

The systems that interact in this manner can be very different. Each app may use a unique programming language, operating system, database, etc. So, how do we create a system that can easily communicate and understand other apps?? This is where the Rest API is used as an interaction system.

When using a RESTful API, we should determine in advance what resources we want to expose to the outside world. Typically, the RESTful API service is implemented, keeping the following ideas in mind:

Format: There should be no restrictions on the data exchange format
Implementation: REST is based entirely on HTTP
Service Definition: Because REST is very flexible, API can be modified to ensure the application understands the request/response format.
The RESTful API focuses on resources and how efficiently you perform operations with it using HTTP.

The features of the REST API design style state:

Each entity must have a unique identifier.
Standard methods should be used to read and modify data.
It should provide support for different types of resources.
The interactions should be stateless.

For REST to fit this model, we must adhere to the following rules:

Client-Server Architecture: The interface is separate from the server-side data repository. This affords flexibility and the development of components independently of each other.
Detachment: The client connections are not stored on the server between requests.
Cacheability: It must be explicitly stated whether the client can store responses.
Multi-level: The API should work whether it interacts directly with a server or through an additional layer, like a load balancer.

#tutorials #api #application #application programming interface #crud #http #json #programming #protocols #representational state transfer #rest #rest api #rest api graphql #rest api json #rest api xml #restful #soap #xml #yaml