fix(openapi): document arrayBuffer bodies

[lxy2500798479]

Closes elysiajs/elysia#1825

Problem

Routes using parse: "arrayBuffer" with a body schema produced an OpenAPI request body with an empty content object:

{
  "requestBody": {
    "content": {}
  }
}

That makes OpenAPI clients infer the request body as missing or undefined.

Fix

Map arrayBuffer request parsers to application/octet-stream when generating request body content. The same mapping is also used when the parser is already declared as application/octet-stream.

Tests

Added a regression in test/openapi/to-openapi-schema.test.ts for:

• parse: "arrayBuffer"
• binary body schema description
• generated requestBody.content["application/octet-stream"]

Verification run:

• bun test test/openapi/to-openapi-schema.test.ts
• git diff --check
• bun run build
• PATH="$PWD/node_modules/.bin:$PATH" bun run test

Summary by CodeRabbit

• New Features

  • Added support for binary request payloads in OpenAPI schema generation. Binary data is now properly documented with application/octet-stream content type, enabling accurate API documentation for endpoints that accept binary data.

• Tests

  • Added test coverage for binary request payload handling in OpenAPI conversion.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 2b5c2d23-a192-486d-9df7-a48fe6406432

📥 Commits

Reviewing files that changed from the base of the PR and between dabaa94 and cb88cc1.

📒 Files selected for processing (2)

• src/openapi.ts
• test/openapi/to-openapi-schema.test.ts

---

Walkthrough

This PR fixes the empty content object in OpenAPI specs when using parse: 'arrayBuffer' with body schemas. It adds handler cases for binary payloads to map them to application/octet-stream media type, plus a test validating the generated schema.

Changes

Binary Request Body Support

Layer / File(s)	Summary
arrayBuffer to application/octet-stream mapping src/openapi.ts, test/openapi/to-openapi-schema.test.ts	Added switch cases handling 'arrayBuffer' and 'application/octet-stream' parse modes to map binary request bodies to application/octet-stream content type in the OpenAPI schema. A new test case verifies the mapping produces the correct media type with schema description and required: true.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Possibly related issues

• #1825: Directly addresses the reported issue where parse: 'arrayBuffer' produces empty content in OpenAPI spec—this PR implements the exact fix of adding arrayBuffer → application/octet-stream handler.

Poem

♡ Binary bodies left out in the cold~
No more empty content, the spec's made whole ♡
arrayBuffer finally gets its media type~ (´・ω・`)
application/octet-stream shines so bright~
Such a small fix, yet oh-so-right~ ୧༼ಠ益ಠ༽୨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change—adding support for documenting arrayBuffer bodies in OpenAPI generation—making it clear and directly related to the changeset.
Linked Issues check	✅ Passed	The PR fully addresses issue #1825 by mapping arrayBuffer parsers to application/octet-stream in request body content generation and includes a regression test.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to fixing the arrayBuffer OpenAPI documentation issue; no unrelated modifications are present.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

Warning

There were issues while running some tools. Please review the errors and either fix the tool's configuration or disable the tool if it's a critical failure.

🔧 ESLint

If the error stems from missing dependencies, add them to the package.json file. For unrecoverable errors (e.g., due to private dependencies), disable the tool in the CodeRabbit configuration.

src/openapi.ts

ESLint skipped: missing config or dependency (missing-dependency). The ESLint configuration references a package that is not available in the sandbox.

test/openapi/to-openapi-schema.test.ts

ESLint skipped: the ESLint configuration for this file references a package that is not available in the sandbox.

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}