N
Nuxt•3d ago
kb

defineCachedEventHandler strips out headers

Anyone know why this is? 
export default defineEventHandler(async (event) => {
 
  console.log('headers', event.node.req.headers)
export default defineEventHandler(async (event) => {
 
  console.log('headers', event.node.req.headers)
this is good ^, i get the headers, (which i need for auth, to pass on) yet changing to defineCachedEventHandler just logs out {} ?
10 Replies
kapa.ai
kapa.ai•3d ago
Hi @kb. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base. :wave: ---------------------- This is a known issue with defineCachedEventHandler in Nuxt. When using the cached version of the event handler, the request headers are not preserved in the cached response. The reason for this behavior is primarily security-related. Headers like cookies and authorization tokens contain sensitive information that shouldn't be cached and reused across different requests. This is similar to how $fetch doesn't forward headers during server-side rendering by default, as explained in the Nuxt documentation:
During Server-Side Rendering, due to security risks such as Server-Side Request Forgery (SSRF) or Authentication Misuse, the $fetch wouldn't include the user's browser cookies, nor pass on cookies from the fetch response. Data Fetching
If you need to access headers for authentication while still using caching, you have a few options: 1. Use a custom cache key function that includes relevant headers in the cache key: 
export default defineCachedEventHandler({
  handler: async (event) => {
    console.log('headers', event.node.req.headers)
    // Your handler logic
    return { data: 'your data' }
  },
  getKey: (event) => {
    // Include auth header in cache key
    const authHeader = getHeader(event, 'authorization')
    return `my-key-${authHeader}`
  }
})
export default defineCachedEventHandler({
  handler: async (event) => {
    console.log('headers', event.node.req.headers)
    // Your handler logic
    return { data: 'your data' }
  },
  getKey: (event) => {
    // Include auth header in cache key
    const authHeader = getHeader(event, 'authorization')
    return `my-key-${authHeader}`
  }
})
2. Use useRequestFetch for forwarding headers in your API calls: 
const requestFetch = useRequestFetch()
const { data } = await useAsyncData(() => requestFetch('/api/your-endpoint'))
const requestFetch = useRequestFetch()
const { data } = await useAsyncData(() => requestFetch('/api/your-endpoint'))
3. Manually pass the headers you need: 
const headers = useRequestHeaders(['authorization'])
const { data } = await useFetch('/api/your-endpoint', { headers })
const headers = useRequestHeaders(['authorization'])
const { data } = await useFetch('/api/your-endpoint', { headers })
This is a security feature rather than a bug, designed to prevent sensitive information from being cached and potentially exposed to other users. ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ----------------------
kapa.ai
kapa.ai•3d ago
<@310160452221140996> Kapa.ai is still learning and improving, please let me know how I did by reacting below.
kb
kbOP•3d ago
@kapa.ai can i access the useRequestHeaders composable from a nitro server route though?
kapa.ai
kapa.ai•3d ago
Let me check the knowledge base for you again. One moment! :books: ---------------------- No, you cannot use the useRequestHeaders composable directly in a Nitro server route. The useRequestHeaders composable is part of Nuxt's client-side and SSR context, not the Nitro server context. In Nitro server routes (like in the server/api/ directory), you should access headers directly from the event object: 
export default defineEventHandler((event) => {
  // Access headers directly from the event
  const headers = event.node.req.headers
  // Or use h3's getHeaders utility
  const headers = getRequestHeaders(event)
  
  // For a specific header
  const authHeader = getHeader(event, 'authorization')
  
  return { headers }
})
export default defineEventHandler((event) => {
  // Access headers directly from the event
  const headers = event.node.req.headers
  // Or use h3's getHeaders utility
  const headers = getRequestHeaders(event)
  
  // For a specific header
  const authHeader = getHeader(event, 'authorization')
  
  return { headers }
})
As shown in the documentation, Nuxt composables like useRequestHeaders are designed to be used within the Nuxt application context (components, pages, plugins) and not within server routes useRequestHeaders. If you need to forward headers from a client request to another API in your server route, you can use event.$fetch which automatically forwards appropriate headers: 
export default defineEventHandler((event) => {
  return event.$fetch('/api/forwarded')
})
export default defineEventHandler((event) => {
  return event.$fetch('/api/forwarded')
})
This approach will forward the request context and headers when making fetch requests in server routes, excluding headers that are not meant to be forwarded Forwarding Context & Headers. I hope this helps clarify how to work with headers in Nitro server routes! ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ----------------------
kapa.ai
kapa.ai•3d ago
<@310160452221140996> Kapa.ai is still learning and improving, please let me know how I did by reacting below.
kb
kbOP•3d ago
@kapa.ai how best to do caching & swr then, in a server nitro route?
kapa.ai
kapa.ai•3d ago
Let me check the knowledge base for you again. One moment! :books: ---------------------- To implement caching and stale-while-revalidate (SWR) in a Nitro server route, you have several options: 1. Using defineCachedEventHandler Despite the header issue you mentioned earlier, this is still the recommended approach for route-level caching: 
export default defineCachedEventHandler({
  handler: async (event) => {
    // Your handler logic here
    return { data: 'your data' }
  },
  // Customize cache key if needed
  getKey: (event) => {
    // You can use URL or query params to create unique keys
    return `my-cache-key-${event.path}-${JSON.stringify(getQuery(event))}`
  },
  // Set cache options
  maxAge: 60 * 10, // Cache for 10 minutes
  staleMaxAge: 60 * 60, // Serve stale content for up to 1 hour while revalidating
  // You can also specify which storage to use
  // storage: 'redis' // if configured
})
export default defineCachedEventHandler({
  handler: async (event) => {
    // Your handler logic here
    return { data: 'your data' }
  },
  // Customize cache key if needed
  getKey: (event) => {
    // You can use URL or query params to create unique keys
    return `my-cache-key-${event.path}-${JSON.stringify(getQuery(event))}`
  },
  // Set cache options
  maxAge: 60 * 10, // Cache for 10 minutes
  staleMaxAge: 60 * 60, // Serve stale content for up to 1 hour while revalidating
  // You can also specify which storage to use
  // storage: 'redis' // if configured
})
2. Using Route Rules in nuxt.config.ts For a more global approach, you can define caching rules in your Nuxt config: 
// nuxt.config.ts
export default defineNuxtConfig({
  nitro: {
    routeRules: {
      '/api/your-route': { 
        swr: 3600, // Cache for 1 hour with SWR behavior
      },
      '/api/another-route/**': { 
        cache: { 
          maxAge: 60,
          staleMaxAge: 3600
        }
      }
    }
  }
})
// nuxt.config.ts
export default defineNuxtConfig({
  nitro: {
    routeRules: {
      '/api/your-route': { 
        swr: 3600, // Cache for 1 hour with SWR behavior
      },
      '/api/another-route/**': { 
        cache: { 
          maxAge: 60,
          staleMaxAge: 3600
        }
      }
    }
  }
})
This approach is particularly useful for setting up caching rules for multiple routes at once Hybrid Rendering. 3. Using Nitro Storage for Custom Caching Logic If you need more control, you can use Nitro's storage layer directly: 
export default defineEventHandler(async (event) => {
  const cacheKey = `my-cache-key-${event.path}`
  const storage = useStorage('data') // or any configured storage
  
  // Try to get from cache
  const cached = await storage.getItem(cacheKey)
  
  if (cached) {
    // Return cached data
    return JSON.parse(cached)
  }
  
  // Fetch fresh data
  const data = await fetchYourData()
  
  // Store in cache
  await storage.setItem(cacheKey, JSON.stringify(data), {
    // Optional expiration if your storage supports it
    expiration: Date.now() + 1000 * 60 * 10 // 10 minutes
  })
  
  return data
})
export default defineEventHandler(async (event) => {
  const cacheKey = `my-cache-key-${event.path}`
  const storage = useStorage('data') // or any configured storage
  
  // Try to get from cache
  const cached = await storage.getItem(cacheKey)
  
  if (cached) {
    // Return cached data
    return JSON.parse(cached)
  }
  
  // Fetch fresh data
  const data = await fetchYourData()
  
  // Store in cache
  await storage.setItem(cacheKey, JSON.stringify(data), {
    // Optional expiration if your storage supports it
    expiration: Date.now() + 1000 * 60 * 10 // 10 minutes
  })
  
  return data
})
Best Practices 1. Cache invalidation: Consider how you'll invalidate cache when data changes. You might need to add timestamps or version identifiers to your cache keys. 2. Vary by headers: If you need to cache differently based on certain headers (like authorization), include them in your cache key: 
getKey: (event) => {
  const authHeader = getHeader(event, 'authorization')
  // Hash the auth header if needed for privacy
  return `data-${event.path}-${authHeader ? computeHash(authHeader) : 'anonymous'}`
}
getKey: (event) => {
  const authHeader = getHeader(event, 'authorization')
  // Hash the auth header if needed for privacy
  return `data-${event.path}-${authHeader ? computeHash(authHeader) : 'anonymous'}`
}
3. Storage options: For production, consider using Redis or other distributed caching solutions instead of the default in-memory cache, especially if you're deploying to serverless environments. 4. Error handling: Implement proper error handling to fall back gracefully when cache operations fail. For Vercel deployments, you might also want to look into Vercel KV for caching, which can be integrated with Nuxt's Nitro server. Remember that caching at the API route level is different from page-level caching with hybrid rendering, so choose the approach that best fits your specific needs. I hope this helps with implementing caching in your Nitro server routes! ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ----------------------
kapa.ai
kapa.ai•3d ago
<@310160452221140996> Kapa.ai is still learning and improving, please let me know how I did by reacting below.
harlan
harlan•3d ago
the headers are striped for security reasons, if you need an auth in the request for it to work then you should use a cachedFunction i think you can use Vary or something to allow the header 🤔 oh it's the second arg of the function defineCachedEventHandler(.., { varies: ['authorization'] })
kb
kbOP•3d ago
ooh

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