fix(proxy): workaround undici issue with DELETE and content-length of 0

[jasenmichael]

Linked issue

• An error occurred when using the proxyRequest method to proxy a DELETE request. #375
• Nitro proxy settings are not taking effect. nuxt/nuxt#19325 (comment)_

❓ Type of change

• 📖 Documentation (updates to the documentation, readme, or JSdoc annotations)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

Description

This pull request addresses the issue of proxy DELETE requests failing when no body or "content-length" header is present.

example error (this PR solves) when making a proxy DELETE request with nuxt3/nitro using h3:

export default defineNuxtConfig({
  routeRules: {
    '/api/**': { proxy: `${apiUrl}/**`},
  }
}

[nuxt] [request error] [unhandled] [500] fetch failed
  at Object.fetch (node:internal/deps/undici/undici:11372:11)  
  at process.processTicksAndRejections (node:internal/process/task_queues:95:5)  
  at async sendProxy (./node_modules/h3/dist/index.mjs:1084:20)  
  at async Object.handler (./node_modules/h3/dist/index.mjs:1680:19)  
  at async Server.toNodeHandle (./node_modules/h3/dist/index.mjs:1890:7)

Fixes:

• Ensures an empty body and "content-length" header for proxy DELETE requests.
• Adds tests to verify the fix.
• DELETE errors related to async sendProxy (./node_modules/h3/dist/index.mjs)

Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly. (Check this box if you've also made documentation changes)

[pi0]

Tests seem to be pass even by commenting out the changes in utils/proxy we might add something that fails without it.

[pi0]

By HTTP spec, it is not disallowed. However conventionally, HTTP servers fail when DELETE omits the body. I'm not sure using a JavaScript HTTP object would be best solution.

[pi0]

Thanks for working on this PR dear @jasenmichael.

I'm not sure if you have already followed but this is relevant issue in undici that causes error (nodejs/undici#2046)

With nodejs/undici#2305, Node.js should now allow content-length of null instead of 0 to explicitly say there is no content which we could try to use instead.

[guibulator]

So nodejs/undici#2305 has been merged since https://github.com/nodejs/undici/releases/tag/v5.27.1.
Nitropack is already using undici 5.28.1. https://github.com/unjs/nitro/blob/b53e00191d0752c7ae7463a907f0858c8bb8182e/package.json#L59
I tried with only setting content-length to 0 or null with no body and it doesn't work. I can only make it work with the fix proposed in this MR.

[pi0]

Nitropack is already using undici 5.28.1

it doesn't depend on any specific version of undici. it is only a dev dependency of the repository itself for another reason (miniflare used in test)

[pi0]

Thanks for your PR dear @jasenmichael. earlier in comments, new tests pass with/without the changes (#605 (comment)) also we cannot do it automatically to provide a probably unwanted body with data of "{}" to the DELETE requests only to bypass a bug in Node.js/undici. (#605 (comment))

This is an important issue and I hope to find a fix but let's track in #375

[jasenmichael]

Thanks for your PR dear @jasenmichael. earlier in comments, new tests pass with/without the changes (#605 (comment)) also we cannot do it automatically to provide a probably unwanted body with data of "{}" to the DELETE requests only to bypass a bug in Node.js/undici. (#605 (comment))

This is an important issue and I hope to find a fix but let's track in #375

Thank you, and yes I realized quickly this pr was not an actual solution, but more of a "use-case workaround", and would break any proxy that requires a DELETE request body to be empty.

After further debugging, I have NOT been able to re-create the issue in a nitro app. Proxied DELETE requests work fine directly in a nitro app, but not through Nuxt3 (both using the same versions of nitro and h3). I spun up the nitro app using the same routeRules used in Nuxt3.

here is my routeRules configuration:

// DELETE does not work through nuxt3, but does work directly in a nitro app.
routeRules: {
  "/dashboard/**": { proxy: "http://localhost:8055/**" },
}

Here is the error that Nuxt3 gives when making a proxied DELETE request:

[nuxt] [request error] [unhandled] [500] fetch failed
  at Object.fetch (node:internal/deps/undici/undici:14062:11)
  at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
  at async sendProxy (./node_modules/h3/dist/index.mjs:506:20)
  at async Object.handler (./node_modules/h3/dist/index.mjs:1247:19)
  at async Server.toNodeHandle (./node_modules/h3/dist/index.mjs:1322:7)

NOTE: When using Nuxt3, I see DELETE requests fail in the browser network tab, but if I edit and re-send with an empty object in the body it succeeds. My pr circumvents this only.

Since this is a proxy, I do not have control over DELETE requests, so sending an empty body is not an option.

Another point to make is - my server (that I am proxying to) does not require a body for DELETE requests, but still succeeds when I send an empty body. A proxied DELETE request through Nuxt3 works ONLY if there is something in the body.

My conclusion is - the failure only occurs when a proxied DELETE request is made through nuxt3 with an empty body.

related: #375

cheers,
btw, unjs is a serious game-changer! excellent work folks 🙏

[pi0]

Thanks for kind words and more details. Well I have to say it is now even more interesting! I will try to make same reproduction as you have with Nuxt. If you have better one, please feel free to share it in #375 that would make help a lot in order to followup.

[trc-mathieu]

Tested with nuxt 3.10 and node 20.11.0 and delete now works fine.