Description

Fixes proxy method binding issue causing request.url and other properties to be inaccessible in plugins when using Express with body parsers in Node.js 24.

Related #2971

Changes

• Fixed Request proxy handler: Added method wrapper to preserve this context when Request methods are accessed through proxy. Prevents "Illegal invocation" errors in Node.js 24.

• Refactored stream writing: Extracted pumpToWritable utility function to consolidate duplicate async iterable and readable stream writing logic. Improves maintainability.

• Updated tests: Added reproduction test for Express + body parser + plugin scenario. Cleaned up console.log statements.

Technical Details

The proxy in normalizeNodeRequest wasn't correctly binding methods when accessed. In Node.js 24's stricter environment with Express body parsers, this caused:

// Before: methods lose their binding when accessed via proxy
const val = Reflect.get(request, prop, receiver);

// After: wrapper preserves correct binding
return function requestMethodWrapper(this: Request, ...args: any[]) {
  return val.apply(this === receiver ? request : this, args);
};

Type of change

• Bug fix (non-breaking change which fixes an issue)
• This change requires a documentation update

How Has This Been Tested?

• Added new test case: express + body_parser + url property in the plugin
• Existing reproduction tests for streaming and compression
• TypeScript type checking passes
• All unit tests pass

Test Environment:

• OS: Linux
• @whatwg-node/server: latest
• NodeJS: 24.x

Checklist:

• I have followed the CONTRIBUTING doc and the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests and linter rules pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

Further comments

The fix maintains backward compatibility while resolving method binding issues that surface under Node.js 24's stricter runtime checks, particularly when middleware like express.json() modifies the request object before it reaches the adapter.

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