N
Nuxt•5d ago
Pablo

[Solved] Storing a user object globally

Greetings! I want to store a user object globally after parsing a JWT in a server plugin, and I seem to only get this partially right. Why am I doing this? Because where my Nuxt app is deployed, authentication happens before the web traffic reaches the Nuxt app. In the request I can see a header with the JWT that has the user info. What I want to happen (which I accomplished easily in Flask in my previous website) is: 1. before any page loads, check if there is a user already in a context/global object. If so, continue. If not, we need to check the request header. 2. parse the JWT in the request header 2. get the user data from a local database 3. store the user object in a app-level state somewhere 4. get the user info in the templates My solution, which is detailed in this StackOverflow question https://stackoverflow.com/questions/79410348/how-to-store-global-user-object-in-nuxt3-server-middleware/79422062#79422062, is to use a server plugin to parse the JWT and a composable "useUser" to store the user state. I can view the user in my templates, which is great. But, in my server plugin, before checking for a JWT, I am not able to check if a user is already in the state. It is always null. I have tried using the nuxtApp, nuxtApp.payload.state, and my useUser composable. This means I have to parse the JWT and fetch the user from a database on every single request. I appreciate any insight into how I can solve this problem, even if it's something different than this current solution. Thanks!
Stack Overflow
How to store global user object in Nuxt3 server middleware?
Using Nuxt 3. Currently I can parse a JWT in the server middleware to get the logged in user, but I want to save that logged in user info to a global variable. Then, on the client side I want to ge...
2 Replies
kapa.ai
kapa.ai•5d ago
Hi @Pablo. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base. :wave: ---------------------- I understand your challenge with storing a user object globally in Nuxt 3 after parsing a JWT in a server plugin. This is a common requirement for authentication systems where the authentication happens upstream. The issue you're facing is related to how Nuxt handles state between server and client, particularly with the server plugin execution context. Let me explain why your current approach isn't working as expected and suggest some solutions. Why Your Current Approach Has Issues When you try to access the state in your server plugin, it's always null because server plugins run very early in the Nuxt lifecycle, before the state is properly initialized and hydrated. The server and client states are separate, and they need to be properly synchronized. Solution Approaches 1. Using useState Correctly The useState composable in Nuxt 3 is designed for creating reactive and SSR-friendly shared state: 
// composables/useUser.js
export const useUser = () => useState('user', () => null)
// composables/useUser.js
export const useUser = () => useState('user', () => null)
However, as you've discovered, this state isn't automatically persisted between requests on the server side. In fact, defining state outside of the proper context can lead to memory leaks as mentioned in the State Management documentation. 2. Server-Side State Initialization A better approach is to initialize your state once on the server and then pass it to the client. You can use the callOnce utility for this: 
// app.vue or a plugin
const user = useState('user')

await callOnce(async () => {
  // Initialize user state from JWT or other source
  user.value = await parseJWTAndGetUser()
})
// app.vue or a plugin
const user = useState('user')

await callOnce(async () => {
  // Initialize user state from JWT or other source
  user.value = await parseJWTAndGetUser()
})
3. Using Cookies for Persistence For true persistence between requests, consider using useCookie instead of useState: 
// composables/useUser.js
export const useUser = () => useCookie('user', {
  default: () => null,
  watch: true,
})
// composables/useUser.js
export const useUser = () => useCookie('user', {
  default: () => null,
  watch: true,
})
This approach was mentioned as a solution in a Stack Overflow post about persisting state between reloads. 4. Middleware Approach You could also use a Nuxt route middleware to check for authentication before rendering pages: 
// middleware/auth.js
export default defineNuxtRouteMiddleware(async (to, from) => {
  const user = useUser()
  
  if (!user.value) {
    // Check JWT in header and set user
    const token = useRequestHeader('authorization')
    if (token) {
      // Parse JWT and set user
      user.value = await parseJWTAndGetUser(token)
    }
  }
})
// middleware/auth.js
export default defineNuxtRouteMiddleware(async (to, from) => {
  const user = useUser()
  
  if (!user.value) {
    // Check JWT in header and set user
    const token = useRequestHeader('authorization')
    if (token) {
      // Parse JWT and set user
      user.value = await parseJWTAndGetUser(token)
    }
  }
})
This middleware would run on both server and client, ensuring your user state is always up to date. Accessing Request Headers To access request headers in your server plugin or middleware, you can use the useRequestHeader composable: 
const authHeader = useRequestHeader('authorization')
const authHeader = useRequestHeader('authorization')
As mentioned in the useRequestHeader documentation, this will return the header value on the server and undefined in the browser. Best Practices 1. Avoid defining state outside of the proper context to prevent memory leaks 2. Use callOnce for one-time initialization 3. Consider using cookies for true persistence between requests 4. Remember that server plugins run very early in the lifecycle By combining these approaches, you should be able to create a solution that checks for an existing user before parsing the JWT on every request, improving the efficiency of your authentication system. ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ----------------------
kapa.ai
kapa.ai•5d ago
<@264260915296337931> Kapa.ai is still learning and improving, please let me know how I did by reacting below.

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