This will only work for SSR

And will not work for client side navigation

It will work for every request

It will only work for every request made to server

When you change route, middleware is executed

^^

Its basically sending a server side request to render that route

Have you tried it out first?

@"use php" Doesn't work

Kindly share code, ss

middleware.js

export function middleware(request) {
    console.log('From middleware')
}

home page

import Link from 'next/link'

export default function Home() {
    return (
        <>
            <p>This is the home page</p>
            <Link href={'/about'}>Go about</Link>
        </>
    )
}

about page

import Link from 'next/link'

export default function Home() {
    return (
        <>
            <p>This is the about page</p>
            <Link href={'/'}>Go home</Link>
        </>
    )
}

It should log From moddleware in the console. And it logs it for requests made to the server

But after loading the home page in the browser, if you navigate to the about page, not request is make to the server.

So, that middleware function isn't called

I think its a xyproblem https://xyproblem.info

nope

Suppose I have something like that

Where I want to call a function before changing route

If the function is client side, Its worth seeing this: https://medium.com/@codingbeautytutorials/nextjs-detect-route-change-bb8e6c316d1

tried something like this. didn't work

If server side, if about has some database logic or similar , middleware should run every time

Okay. So, in the actual application I want to check some tokens before going to another route. If the token is valid, I want to proceed, otherwise I want to redirect to another route.

@"use php" How would you do something like that?

Wait you are not exporting a matched

It's just an example

I’ll try it in my personal playground in some time and let you know

If the request is made to the server, then server can check the token and proceed or redirect to another route.
But if no request is made to the server (client-side routing), then that middleware won't execute. So, the token isn't checked.

@Pip gall wasp So I've confirmed that unless the route is cached on the client side, It'll send a request to server side

So if someone goes from / to /about, middleware will execute, but not vice versa because / is already cached

Yeah. I've also noticed that. But is there any way to achieve that?

Is there any way to execute a function every time before route change?

You can check everytime in page.tsx.

I wouldn't recommend actually, because token will most likely be active. And incase it gets inactive, user can just refresh the page