Nuxt•2w ago

How to keep state in SSR requests?

Hey, I am validating a session token by hitting a DB. I see it is hitting the DB once for every SSR request (e.g. useAsyncData.) How can I avoid the DB hit per SSR request?

26 Replies

Felix•2w ago

So I have a 00.auth.ts middleware in server/middleware. It seems this middleware runs for every SSR request. My understanding that since it's server rendered all the state of the original request should be available. But the middleware runs repeatedly and the event object is a new object so I cannot cache state on it either

manniL•7d ago

cache the result in your API endpoint might be the easiest

Felix•7d ago

by what key?

manniL•7d ago

the session token itself? 🤔

Felix•7d ago

right i see... just store it in memory somewhere to fake the db lookup? assuming that it will soon get evicted because the lambda dies? what i don't understand is it's just a function call; the context is already on the stack somehwere. is it not possible to somehow access this?

manniL•7d ago

well you can save it e.g. in a kv store in-mem is tricky with serverless

the context is already on the stack somehwere. is it not possible to somehow access this?

No, it is recreated per call 🙂

Felix•7d ago

Oh why is that

manniL•7d ago

Various reasons, e.g. that you don't want cross state pollution 🙂

Felix•7d ago

What is cross state pollution?

manniL•7d ago

state of user a is "accidentally" part of state of user b and with serverless or edge, you can't have a "consistently" shared context anyway (same with any multi instance deployment) you can still use plugins to make sure that each requests has a certain object/class/... available though

Felix•7d ago

But if initial request binds to user a then for that request context how could it ever be user b?

manniL•7d ago

oh wait maybe we are misunderstanding here 🙂 I am talking about multiple initial requests

Felix•7d ago

I really don't get it. So request flies in, route is matched, handler runs, some $fetch calls happen and since we are on the server a FN runs instead of a http req. In that FN all the context should be available no? Right. I'm taking about a single initial request. I made sure no other xhr requests show in the network tab. But event.context is always cleared and I don't know how I can access the initial request context

manniL•7d ago

you could get the event via useRequestEvent()

Felix•7d ago

What I am seeing is that for every $fetch the entire server/Middleware runs again on a fresh event object. Wouldn't getRequestEvent just return that?

manniL•7d ago

no, this is correct. it is treated the same way when doing an "external" request to that endpoint

Felix•7d ago

Which brings me back to why and how

manniL•7d ago

https://www.youtube.com/watch?v=DkvgJa-X31k might help you there

Alexander Lichter

YouTube

Nuxt vs. Nitro - What does what in your App

🤝🏻 Nuxt and Nitro go hand in hand - but sometimes so well that the borders between both blur for developers. Wouldn't it be helpful to understand why Pinia composables can't be used in the server folder and when exactly Nitro comes into play? Fear no more - all of that and more will be covered in this video! Key points: 👀 When Nitro is used in ...

manniL•7d ago

think of nitro as standalone api server which also renders your nuxt app but these are distinct tasks

Felix•7d ago

Sorry if I come across rude but I don't understand how sth so simple can be made to be so difficult it can't be explained in one sentence . Kind of baffling. I'm surprised I also couldn't find answers on google. I love working with Nuxt overall. This is the first hol'on a minute moment. I'll give the video a watch tonight.

manniL•7d ago

I'm happy to try again. Could you maybe reword the question? When you do calls "on the client side" of your app to an API endpoint, then it is simply not different than when calling them via postman or just putting the URL in the browser (except you might pass headers and similar to them) Commonly you authenticate your user with the session ID, send the ID to the API and your backend will check validity. This is the case for any kind of stateless API

Felix•7d ago

Yup but $fetch short-circuits and runs the code immediately on the server during the initial request. No client involved For SSR pages

manniL•7d ago

that's correct, on the server it does! There, $fetch calls are not actually happening but are emulated because you can just run the event handler's code 👍 But not on the client side, as you said

Felix•6d ago

Yes... So on the server why can't I get access to state established in the initial request object I noticed that when I do a $fetch from my middleware/01.auth.global.ts middleware, the initial event context is retained! That is what I want. But why is this not happening for $fetch requests issued in page components is what I am trying to figure out. I cloned nuxt and will start digging... ok. so idk if this is a bug in nuxt or not. but check this out:

const x = useAsyncData(
  () => {
    // this will  NOT retain context in SSR call:
    const fetch = $fetch;

    // this retains context in SSR call:
    // const fetch = useRequestFetch();

    return fetch("/api/user");
  },
  {
    immediate: true,
    server: true,
    watch: false,
  },
);

const x = useAsyncData(
  () => {
    // this will  NOT retain context in SSR call:
    const fetch = $fetch;

    // this retains context in SSR call:
    // const fetch = useRequestFetch();

    return fetch("/api/user");
  },
  {
    immediate: true,
    server: true,
    watch: false,
  },
);

Felix•6d ago

created a repro here https://github.com/felixSchl/nuxt-ssr-context-bug/blob/3addb782689582efa3155a0f410a837e108658dd/app.vue#L5-L7

GitHub

nuxt-ssr-context-bug/app.vue at 3addb782689582efa3155a0f410a837e108...

Contribute to felixSchl/nuxt-ssr-context-bug development by creating an account on GitHub.

Felix•6d ago

and filed a bug. we'll see what comes of it.. https://github.com/nuxt/nuxt/issues/27909

GitHub

SSR Context Lost · Issue #27909 · nuxt/nuxt

Environment Operating System: Darwin Node Version: v21.6.2 Nuxt Version: 3.12.2 CLI Version: 3.12.0 Nitro Version: 2.9.7 Package Manager: pnpm@8.8.0 Builder: - User Config: ssr, devtools Runtime Mo...

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How to keep state in SSR requests?