Building RESTful APIs with Express

Express is a minimal and flexible Node.js web application framework that provides a robust set of features for building APIs. In this guide, we will build a simple RESTful API using Express.

Setting Up the Project

First, initialize a new Node.js project and install Express:

bash
1npm init -y
2npm install express

Create a file called server.js and add the following code:

javascript
1const express = require("express");
2const app = express();
3const port = 3000;
4
5app.use(express.json()); // Middleware to parse JSON request bodies
6
7app.get("/api/posts", (req, res) => {
8  res.json([{ id: 1, title: "First Post" }]);
9});
10
11app.listen(port, () => {
12  console.log(`Server running on http://localhost:${port}`);
13});

Adding More Routes

Let's expand our API by adding routes to handle CRUD operations.

javascript
1let posts = [
2  { id: 1, title: "First Post", content: "This is the first post" },
3  { id: 2, title: "Second Post", content: "This is the second post" },
4];
5
6// Get all posts
7app.get("/api/posts", (req, res) => {
8  res.json(posts);
9});
10
11// Get a single post by ID
12app.get("/api/posts/:id", (req, res) => {
13  const post = posts.find((p) => p.id === parseInt(req.params.id));
14  if (!post) return res.status(404).json({ message: "Post not found" });
15  res.json(post);
16});
17
18// Create a new post
19app.post("/api/posts", (req, res) => {
20  const newPost = {
21    id: posts.length + 1,
22    title: req.body.title,
23    content: req.body.content,
24  };
25  posts.push(newPost);
26  res.status(201).json(newPost);
27});
28
29// Update a post
30app.put("/api/posts/:id", (req, res) => {
31  const post = posts.find((p) => p.id === parseInt(req.params.id));
32  if (!post) return res.status(404).json({ message: "Post not found" });
33
34  post.title = req.body.title || post.title;
35  post.content = req.body.content || post.content;
36  res.json(post);
37});
38
39// Delete a post
40app.delete("/api/posts/:id", (req, res) => {
41  posts = posts.filter((p) => p.id !== parseInt(req.params.id));
42  res.json({ message: "Post deleted successfully" });
43});

Testing the API

You can test the API using a tool like Postman or by using curl commands in the terminal.

Example curl command to get all posts:

bash
1curl http://localhost:3000/api/posts

Conclusion

You’ve now built a basic RESTful API using Express with CRUD operations. You can extend this by adding a database, authentication, and more advanced features!