update, now you can use getServerSideProps
and nextjs
provides an easy way to get user cookie : How to use cookie inside `getServerSideProps` method in Next.js?
--------- old answer ---------
simple answer: use cookie, code refer https://github.com/nextjs-boilerplate/next.js-boilerplate https://github.com/nextjs-boilerplate/next-fetch
-- details --
I had the same question when I first adopt next.js
, as it worked in react, people prefer use a token to tag authed user and fetch always run in front-end. But as next.js
made ssr
a build in feature, I tried and find auth by cookie is possible, and I start https://github.com/nextjs-boilerplate/next.js-boilerplate and split out a fetch based on cookie https://github.com/nextjs-boilerplate/next-fetch
-- how it works --
1.client side fetch: use fetch option option.credentials = 'include'
and option.headers.Cookie=document.cookie
will patch cookie into your request. Bnd when fetch back result, this become wired, you cannot access cookie header, so you have to use another header and additional logic needed in backend logic like res.header('custom-set-cookie', res.getHeader('set-cookie'))
2.server side fetch: first you need the express request object, and get cookie like req.headers.cookie
, then pack it into fetch request option. when fetch back, get cookie like r.headers._headers[cookieHeaderName]
and pack into response res.header('set-cookie', setCookie)
then after you pack this transfer up, you can simply call a json api and cookie will automatically transfered. And if you don't need to change cookie through header (you can through js), you can ommit the extra handle like res.header('custom-set-cookie', res.getHeader('set-cookie'))
in api
you can try my ssr login
here http://nextjs.i18ntech.com/login