Creating a RESTful API - Part 2

Introduction

Throughout the first part, we've learned how to create a very basic RESTful API, which could be used to communicate with our back-end architecture and fetch data from our database. During this post, I'm going to test this API locally in a simple example to understand its technical usage.

Adding Helmet

Our first step is to install a new package called helmet to our dependencies. It is used to automatically secure our app by setting various HTTP headers.

npm i helmet

New Routes folder

Next, we're going to create a new folder called routes in the root directory and add a file inside this folder called msgs.js. This file stands for a specific route (msgs route) that contains one or more http method/s (GET, POST, PUT, DELETE).

Now open this newly created msgs.js route, and add the following:

import express from "express"

const router = express.Router()

const msgs = [
    {
        "id": "1",
        "content": "Hey there my friends!"
    },
    {
        "id": "2",
        "content": "Hello hello hello!"
    },
    {
        "id": "3",
        "content": "I hope everything is great!"
    },
    {
        "id": "4",
        "content": "How are you today?"
    }
];

router.get('/', (req, res) => {
    res.send(msgs);
});

export default router

Modifying index.js

Next, we'll modify our index.js file as follows:

import express from "express"
import cors from "cors"
import helmet from "helmet"
import msgsRoute from "./routes/msgs.js"

const app = express()
const port = process.env.PORT || 5000

const corsOptions = {
    origin: "*",
    "Access-Control-Allow-Origin": true,
    optionSuccessStatus: 200,
}

app.use(cors(corsOptions))
app.use(express.urlencoded({ extended: false }))
app.use(express.json())
app.use(helmet())

app.use("/msgs", msgsRoute)

app.get("/", (req, res) => {
    res.send("Welcome to our RESTful API!")
})

app.use((req, res, next) => {
    const error = new Error("Something went wrong")
    error.status = 404
    next(error)
})
app.use((error, req, res, next) => {
    res.status(error.status || 500)
    res.json({
        error: {
            message: error.message,
        },
    })
})

app.listen(port, (err) => {
    if (err) throw new Error("Error while connecting to the server")
    console.log(`Server is live and running at: http://localhost:${port}`)
})

export default app

The only changes we've made from our setup in part-1 are:

• calling helmet package on our app
• Initializing a corsOptions object and passing it as an argument when we called cors()
• calling our msgs route to be able to consume it

Testing using Thunder client

Last but not least, open your terminal, and type the following script:

npm run start-dev

Now that our server is live, we'll test our API endpoints using any API testing tool, such as postman. But I prefer to use Thunder client which is a VS code extension for simple API testing. After installing the extension, open it from the left bar (or ctrl + shift + p and search for thunder client), add the API endpoint on top and click send:

Final Thoughts

In this example, we've tested our API locally using a simple msgs array to simulate a database model and fetch its items. While this is a basic implementation, it serves as a good starting point for beginners to understand API functionality. Click here for the source code. In the next blog post, I'll demonstrate how to connect this API to MongoDB and implement additional HTTP methods (PUT, POST, DELETE) to modify the database collection.

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💡 Pro Tip: Organize your API requests into collections in Thunder Client or Postman to better manage different environments and make sharing API documentation easier with your team.