How to access query params in Next.js SSG, ISR [duplicate] - next.js

Question

I want to get query string from URL on Next.js static site generation.
I found a solution on SSR but I need one for SSG.
Thanks

Answer 1

import { useRouter } from "next/router";
import { useEffect } from "react";
const router = useRouter();
useEffect(() => {
if(!router.isReady) return;
const query = router.query;
}, [router.isReady, router.query]);
It works.

Answer 2

I actually found a way of doing this
const router = useRouter()
useEffect(() => {
const params = router.query
console.log(params)
}, [router.query])

Answer 3

As other answers mentioned, since SSG doesn't happen at request time, you wouldn't have access to the query string or cookies in the context, but there's a solution I wrote a short article about it here https://dev.to/teleaziz/using-query-params-and-cookies-in-nextjs-static-pages-kbb
TLDR;
Use a middleware that encodes the query string as part of the path,
// middleware.js file
import { NextResponse } from 'next/server'
import { encodeOptions } from '../utils';
export default function middleware(request) {
if (request.nextUrl.pathname === '/my-page') {
const searchParams = request.nextUrl.searchParams
const path = encodeOptions({
// you can pass values from cookies, headers, geo location, and query string
returnVisitor: Boolean(request.cookies.get('visitor')),
country: request.geo?.country,
page: searchParams.get('page'),
})
return NextResponse.rewrite(new URL(`/my-page/${path}`, request.nextUrl))
}
return NextResponse.next()
}
Then make your static page a folder that accepts a [path]
// /pages/my-page/[path].jsx file
import { decodeOptions } from '../../utils'
export async function getStaticProps({
params,
}) {
const options = decodeOptions(params.path)
return {
props: {
options,
}
}
}
export function getStaticPaths() {
return {
paths: [],
fallback: true
}
}
export default function MyPath({ options }) {
return <MyPage
isReturnVisitor={options.returnVisitor}
country={options.country} />
}
And your encoding/decoding functions can be a simple JSON.strinfigy
// utils.js
// https://github.com/epoberezkin/fast-json-stable-stringify
import stringify from 'fast-json-stable-stringify'
export function encodeOptions(options) {
const json = stringify(options)
return encodeURI(json);
}
export function decodeOptions(path) {
return JSON.parse(decodeURI(path));
}

Answer 4

You don't have access to query params in getStaticProps since that's only run at build-time on the server.
However, you can use router.query in your page component to retrieve query params passed in the URL on the client-side.
// pages/shop.js
import { useRouter } from 'next/router'
const ShopPage = () => {
const router = useRouter()
console.log(router.query) // returns query params object
return (
<div>Shop Page</div>
)
}
export default ShopPage
If a page does not have data fetching methods, router.query will be an empty object on the page's first load, when the page gets pre-generated on the server.
From the next/router documentation:
query: Object - The query string parsed to an object. It will be
an empty object during prerendering if the page doesn't have data
fetching
requirements.
Defaults to {}
As #zg10 mentioned in his answer, you can solve this by using the router.isReady property in a useEffect's dependencies array.
From the next/router object documentation:
isReady: boolean - Whether the router fields are updated
client-side and ready for use. Should only be used inside of
useEffect methods and not for conditionally rendering on the server.

Answer 5

you don't have access to the query string (?a=b) for SSG (which is static content - always the same - executed only on build time).
But if you have to use query string variables then you can:
still statically pre-render content on build time (SSG) or on the fly (ISR) and handle this route by rewrite (next.config.js or middleware)
use SSR
use CSR (can also use SWR)