How to Use Route Handlers in Next.js 14

Next.js is a popular React framework that simplifies server-side rendering and the building of static web applications. One of the core features of Next.js is its flexible routing system, which allows developers to create custom routes and define how they handle incoming requests.

With the release of Next.js 14, the routing system has been improved and enhanced with several new features and changes. One of the most notable additions is the support for Route Handlers, which are functions that are executed when users access site routes. Route Handlers are responsible for handling incoming HTTP requests for the defined URLs or routes to produce the required data.

In this article, we will take a closer look at Route Handlers in Next.js 14, the benefits they offer, and how you can implement them in a Next.js application.

What are Route Handlers in Next.js 14?

Route Handlers are functions that are exported from a page file as middleware that intercepts incoming requests. They can be used to perform various tasks, such as:

• Validating and parsing request parameters and body
• Performing authentication and authorization checks
• Fetching data from external sources
• Manipulating and transforming data
• Sending custom responses with headers, status codes, and body
• Redirecting or rewriting requests to other routes
• Handling errors and exceptions

Route Handlers can be nested inside the app directory, similar to page.js and layout.js. But there cannot be a route.js file at the same route segment level as page.js.

Route Handlers support the following HTTP methods: GET, POST, PUT, PATCH, DELETE, HEAD, and OPTIONS. If an unsupported method is called, Next.js will return a 405 Method Not Allowed response.

How to Create a Route Handler in Next.js 14?

To create a Route Handler in Next.js 14, you need to follow these steps:

1. Create a file with the name route.js inside the app directory. The file name should match the route path that you want to handle. For example, if you want to handle the /posts route, you should create a file named app/posts/route.js.
2. Export a function from the file with the name of the HTTP method that you want to handle. For example, if you want to handle the GET method, you should export a function named get. The function should accept two parameters: req and res, which are the request and response objects from Node.js.
3. Write the logic for handling the request inside the function. You can use the req and res objects to access and manipulate the request and response data. You can also use the next function to pass the control to the next middleware or the page component. You should always end the function with either res.send, res.json, res.redirect, res.writeHead, res.end, or next, otherwise the request will hang.
4. Optionally, you can export a function named config from the file to configure the Route Handler. The config function should return an object with the following properties:
   • api: A boolean value that indicates whether the Route Handler is an API route or not. If true, the Route Handler will be treated as an API route and will not render any page component. The default value is false.
   • middleware: An array of middleware functions that will be executed before the Route Handler. The middleware functions should accept three parameters: req, res, and next, and should call next to pass the control to the next middleware or the Route Handler.
   • priority: A number that indicates the priority of the Route Handler. The lower the number, the higher the priority. The default value is 0.

How to Use a Route Handler in Next.js 14?

To use a Route Handler in Next.js 14, you need to follow these steps:

1. Create a page component for the route that you want to handle. The page component should be a React component that accepts a props object as a parameter. The props object will contain the data that is returned from the Route Handler or the getServerSideProps or getStaticProps functions. The page component should render the UI for the route using the props data.
2. Import the Route Handler file from the app directory and pass it as the second argument to the export default statement of the page component. For example, if you have a page component named pages/posts.js and a Route Handler file named app/posts/route.js, you should write something like this:

// pages/posts.js
import React from 'react'
import route from '../app/posts/route'

function PostsPage(props) {
// render the UI for the posts page using the props data
}

export default PostsPage, route

1. Optionally, you can also use the getServerSideProps or getStaticProps functions to fetch data at build time or request time and pass it to the page component as props. The data returned from these functions will be merged with the data returned from the Route Handler. For example, if you have a getStaticProps function that fetches some data from an external API, you can write something like this:

// pages/posts.js
import React from 'react'
import route from '../app/posts/route'

function PostsPage(props) {
// render the UI for the posts page using the props data
}

export async function getStaticProps() {
// fetch some data from an external API
return {
props: {
// data from the API
},
}
}

export default PostsPage, route


What are the Benefits of Route Handlers in Next.js 14?

Route Handlers in Next.js 14 offer several benefits, such as:

• They provide a clear and consistent way to handle requests and responses for different routes in the web application.
• They allow developers to write custom logic and middleware for each route, without affecting the page component or the global app configuration.
• They enable developers to use different HTTP methods for the same route, and handle them accordingly.
• They improve the performance and scalability of the web application, as they reduce the need for custom servers or proxies.
• They simplify the code structure and organization, as they keep the routing logic and the UI logic separate.

Conclusion

Route Handlers are a powerful and convenient feature of Next.js 14 that allow developers to create custom routes and handle incoming requests. They are functions that are exported from a page file as middleware that intercepts incoming requests and returns the required data. They can be used to perform various tasks, such as validating and parsing request parameters and body, performing authentication and authorization checks, fetching data from external sources, manipulating and transforming data, sending custom responses with headers, status codes, and body, redirecting or rewriting requests to other routes, handling errors and exceptions, and more.

In this article, we have learned what Route Handlers are, how to create and use them, and what benefits they offer. We hope that this article has helped you to understand and appreciate Route Handlers in Next.js 14, and that you will use them in your next web project.

This is the end of the article. I hope you enjoyed reading it.

If you want to learn more you can check out official documentation.