Next.js - API MiddleWares

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API Routes in Next.JS have built-in middlewares which helps in parsing the incoming request.

Following are the middlewares

• req.cookies − cookies object contains the cookies sent by the request. Default value is {}.

• req.query − query object contains the query string. Default value is {}.

• req.body − query object contains the request body parsed using 'content-type'. Default value is null.

Let's create an example to demonstrate the same.

In this example, we are going to update an user.js in pages/api directory.

Let's update the nextjs project used in API Routes chapter.

Create user.js file in pages/api directory as following.

export default (req, res) => {
   res.statusCode = 200
   res.setHeader('Content-Type', 'application/json')
   res.end(JSON.stringify({ query: req.query }))
}

Start Next.js Server

Run the following command to start the server −.

npm run dev

> nextjs@1.0.0 dev D:\Node\nextjs
> next

ready - started server on http://localhost:3000
info  - Loaded env from D:\Node\nextjs\.env.local
event - compiled successfully
event - build page: /api/user
wait  - compiling...
event - compiled successfully
event - build page: /next/dist/pages/_error
wait  - compiling...
event - compiled successfully

Verify Output

Open http://localhost:3000/api/user?counter=1 in a browser and you will see the following output.

{"query":{"counter":"1"}}