framework: fix vary header

[renbaoshuo]

Summary by CodeRabbit

• Bug Fixes
  • Improved response caching behavior by including content negotiation in the Vary response header.
  • Preserved existing Vary header values when handling CORS responses, improving compatibility with caches and clients that rely on multiple request headers.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Advanced

Run ID: 0cc3c3c4-a629-42dd-af62-8d0fa2a1721b

📥 Commits

Reviewing files that changed from the base of the PR and between 6635257 and e8e69b9.

📒 Files selected for processing (2)

• framework/framework/base.ts
• framework/framework/server.ts

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Walkthrough

The base Koa middleware now adds Accept to the Vary response header when a request has a handler. CORS handling now uses Koa's vary() method for Origin and Referer, which merges these values with existing Vary values instead of overwriting them.

Priority: ⬇️ Low

Estimated code review effort: 1 (Trivial) | ~5 minutes

Change: Bug fix

Suggested reviewers: undefined-moe

Merge Risk: ⚪ Minimal · up to e8e69

The Vary-header changes should merge existing response variation values without introducing a known runtime or compatibility risk.

🚥 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 clearly and concisely describes the main change: fixing Vary header handling in the framework.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 2…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

Warning

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🔧 ESLint

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framework/framework/base.ts

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

framework/framework/server.ts

ESLint skipped: the matched ESLint configuration already failed (missing-dependency).

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