fix(aws-lambda-streaming): handle empty body

[taylorfsteele]

Resolves #204

When the request body is null the response stream doesn't close. This breaks responses like redirects that don't have a body:

return new Response(null, {
   status: 302,
   headers: {
     location: "/",
   },
});

This PR adds in the conditional logic to create a response body if none exists.

Summary by CodeRabbit

Release Notes

• Bug Fixes
  • Enhanced handling of AWS Lambda responses that lack a response body, ensuring proper stream closure and metadata delivery
  • Improved streaming behavior for responses without body content (such as redirects), maintaining correct status codes and headers in the stream

[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: 1e793dd0-0997-406c-aa9d-596aa1703a85

📥 Commits

Reviewing files that changed from the base of the PR and between c853aa9 and 08375ab.

📒 Files selected for processing (2)

• src/adapters/_aws/utils.ts
• test/aws.test.ts

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📝 Walkthrough

Walkthrough

This PR fixes AWS Lambda streaming responses that lack bodies (such as redirects). The awsStreamResponse utility now creates a default empty ReadableStream when the response body is absent, ensuring the metadata and stream close operations complete rather than returning early. Tests verify the empty-string chunk is written and writer.end() is called for both empty bodies and redirect scenarios.

Changes

AWS Lambda Streaming Response Handling

Layer / File(s)	Summary
Handle missing response bodies src/adapters/_aws/utils.ts	awsStreamResponse substitutes an empty ReadableStream when response.body is absent, replacing the early return pattern and allowing streaming to proceed through the full try/finally flow.
Test empty body streaming behavior test/aws.test.ts	Updated empty-body test now asserts a single empty-string chunk is written and writer.end() is called; new test validates redirect (302) responses without bodies stream metadata and close correctly.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• h3js/srvx#104: Introduced the core AWS Lambda adapter utilities including the awsStreamResponse function that this PR now extends to handle missing response bodies.

Suggested reviewers

• pi0

Poem

🐰 A stream without a body, who knew?
Now redirects fly through clean and true,
Empty reads create the flow,
Metadata writes put on a show,
Lambda's Lambda, all fixed anew! ✨

🚥 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 'fix(aws-lambda-streaming): handle empty body' is concise, specific, and accurately describes the primary change—handling AWS Lambda streaming responses when the body is absent or null.
Linked Issues check	✅ Passed	The PR successfully addresses issue #204 by implementing conditional logic to create a default empty ReadableStream when response.body is absent, allowing streaming responses without bodies to complete correctly without timing out.
Out of Scope Changes check	✅ Passed	All changes are scoped to fixing the AWS Lambda streaming body handling issue: the utils function implementation handles empty bodies, and test updates verify the fix for both empty bodies and redirect responses.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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