1. Introduction

In this tutorial, we will learn how to integrate REST APIs into hybrid mobile applications. The goal is to understand how to make HTTP requests from our app to a server and how to handle the responses.

By the end of this tutorial, you should be able to:

• Understand what REST APIs are
• Make HTTP requests from a hybrid app
• Handle HTTP responses
• Understand HTTP methods (GET, POST, PUT, DELETE)

Prerequisites:

• Basic knowledge of JavaScript
• Understanding of HTTP and RESTful APIs
• Familiarity with any hybrid mobile development framework (like React Native, Ionic, etc.)

2. Step-by-Step Guide

2.1 Understanding REST APIs

REST (Representational State Transfer) APIs are a way to communicate with a server. They allow us to perform CRUD operations (Create, Read, Update, Delete) over the HTTP protocol.

2.2 Making HTTP Requests

In JavaScript, we can use the fetch API to make HTTP requests. The fetch function returns a promise that resolves to the Response object representing the response to the request.

Example:

fetch('https://api.example.com/items')
  .then(response => response.json())
  .then(data => console.log(data));

2.3 Handling HTTP Responses

In the previous example, we first convert the response to JSON format using the response.json() method, and then we handle the data.

3. Code Examples

3.1 GET Request

// fetch API to make a GET request
fetch('https://api.example.com/items')
  .then(response => {
    if (!response.ok) {
      throw new Error(`HTTP error! status: ${response.status}`);
    }
    return response.json();
  })
  .then(data => console.log('This is your data', data))
  .catch(error => console.log('There was a problem with your fetch', error));

3.2 POST Request

// fetch API to make a POST request
fetch('https://api.example.com/items', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    name: 'Item name',
    description: 'Item description',
  }),
})
.then(response => response.json())
.then(data => console.log(data))
.catch((error) => {
  console.error('Error:', error);
});

4. Summary

In this tutorial, we learned:

• What REST APIs are
• How to make HTTP GET and POST requests from a hybrid app
• How to handle HTTP responses

Next, you can learn about PUT and DELETE requests, and try integrating more complex APIs into your app. Check out the MDN Web Docs for more on the fetch API.

5. Practice Exercises

1. Make a GET request to fetch a list of users from 'https://jsonplaceholder.typicode.com/users'
2. Make a POST request to add a new user to 'https://jsonplaceholder.typicode.com/users'

Remember to handle errors and responses appropriately. Happy coding!