[nuxt] [request error] [unhandled] [500] using `proxyRequest` or `sendProxy`

[pavloniym]

Environment

node: v18.12.0
nuxt: 3.4.0

Reproduction

This is the code for the server middleware in my Nuxt project:

export default defineEventHandler((event) => {

    const backendEndpoint = 'https://api.mybackend.com'
    const pathsWithProxyToBackend = ['/api', '/storage']

    if (event.node.req.url) {
        if (pathsWithProxyToBackend?.filter((path: string) => event.node.req.url?.startsWith(path))?.length > 0) {
            return proxyRequest(event, new URL(event.node.req.url, backendEndpoint).toString())
        }
    }

    return
})

Describe the bug

Some of my requests throw 500 error

[nuxt] [request error] [unhandled] [500] Cannot read properties of null (reading 'Symbol(Symbol.asyncIterator)')                                                                            20:30:53
  at sendProxy (./node_modules/h3/dist/index.mjs:552:38)
  at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
  at async Object.handler (./node_modules/h3/dist/index.mjs:1247:19)
  at async Server.toNodeHandle (./node_modules/h3/dist/index.mjs:1322:7)

There is no logic ...
On next page refresh other requests throws same error (500 code) (or no errors and all requests are 200 code)

Please help! Thanks

Additional context

No response

Logs

Nuxt response with error

{
    "url": "/storage/releases/posters/9407/xRI8qpbLlmYGn0gy__faeb17923a3a62917671d76d38019a15.webp",
    "statusCode": 500,
    "statusMessage": "",
    "message": "Cannot read properties of null (reading 'Symbol(Symbol.asyncIterator)')",
    "stack": "<pre><span class=\"stack internal\">at sendProxy (./node_modules/h3/dist/index.mjs:552:38)</span>\n<span class=\"stack internal\">at process.processTicksAndRejections (node:internal/process/task_queues:95:5)</span>\n<span class=\"stack internal\">at async Object.handler (./node_modules/h3/dist/index.mjs:1247:19)</span>\n<span class=\"stack internal\">at async Server.toNodeHandle (./node_modules/h3/dist/index.mjs:1322:7)</span></pre>"
}

Response headers of request

HTTP/1.1 500 Not Modified
Access-Control-Allow-Origin: *
alt-svc: h3=":443"; ma=86400, h3-29=":443"; ma=86400
cache-control: max-age=14400
cf-cache-status: MISS
cf-ray: 7b7dade0d8331c0-OSL
date: Fri, 14 Apr 2023 17:30:53 GMT
etag: "6433cfc-3ac"
last-modified: Mon, 10 Apr 2023 08:58:50 GMT
nel: {"success_fraction":0,"report_to":"cf-nel","max_age":604800}
referrer-policy: no-referrer-when-downgrade
report-to: {"endpoints":[{"url":"https:\/\/a.nel.cloudflare.com\/report\/v3?s=ZBgKefuS7%2FBCMgT93ZMXv0akCngAvd8TF%2FXVUtr64yf%2FSnUxsrV9PX1D"}],"group":"cf-nel","max_age":604800}
server: cloudflare
vary: Accept-Encoding
x-content-type-options: nosniff
x-frame-options: SAMEORIGIN
x-xss-protection: 1; mode=block
content-type: application/json
content-length: 663

[T-x-T]

I had a similar issue that was fixed by going back to nodejs version 16. Maybe this helps you too

[pavloniym]

@T-x-T
Downgraded to node v16.18.0 — same error

[pavloniym]

This issue connected with 304 status code of server response -> nitrojs/nitro#1237

[pi0]

Hi. It is impossible to 100% confirm if issue is fixed or related to h3 directly since reproduction is with nuxt and nitro setup. However i think issues might be fixed in latest h3/nitro builds we have landed many related fixes for streaming and proxy.

Please consider trying nitro edge and ping me / create issue in nuxt or nitro if still having problems on edge 🙏🏼