dotcom-arcade/DOCUMENTATION_UPDATES.md

Documentation Updates - Second Pass Code Review

Date: 2026-02-06

Updated the following game-service documentation files to reflect medium and low severity fixes from the second pass code review:

Files Updated

1. docs/05-game-service/gamezip-server.md

Added section "Download Reliability Improvements" documenting:

• findActiveDownload() now correlates downloads with hostname from request path instead of returning first arbitrary download (ensures correct download status on concurrent requests)
• Stale download cleanup extracted to shared cleanupStaleDownloads() method (DRY principle, shared between functions)
• new URL() calls wrapped in try-catch for proper 400 error handling on malformed URLs (prevents 500 errors)

2. docs/05-game-service/zip-manager.md

Added section "Performance Improvement - findFile() Refactoring" documenting:

• findFile() method optimized for single-pass lookup
• Entries read directly without redundant delegation through getFile()
• Process: index check → entry existence check → size check → read
• Eliminates intermediate function calls and extra lookups
• Result: Faster file discovery with fewer function invocations

3. docs/05-game-service/legacy-server.md

Added section "Dynamic Configuration Loading" documenting:

• Settings now fetched fresh via ConfigManager.getSettings() at the start of each serveLegacy() call instead of being captured once at construction
• Ensures configuration changes (Brotli, external URLs, override paths) take effect immediately without restart
• Benefit: Admin users can update proxy settings via UI without downtime

4. docs/05-game-service/proxy-server.md

Updated "CORS Handling" section:

• CORS headers now use shared setCorsHeaders utility from utils/cors.ts
• Utility includes all required methods: GET, POST, DELETE, OPTIONS
• Eliminates duplication across both proxy servers
• Consistent CORS configuration across the module

5. docs/05-game-service/architecture.md

Added major section "Code Quality & Security Improvements (Second Pass Review)" documenting all medium and low severity fixes:

HTML Injection & Logging:

• htmlInjector.ts now uses project logger instead of console.log
• Dead code branch removed from polyfill injection logic

PreferencesService Initialization:

• Logs warning on re-initialization with different path
• Prevents silent configuration changes affecting game downloads

Schema Validation:

• Hostname schema minimum length corrected to 2 (matches regex requirement)

Regex Pattern Fixes:

• pathSecurity.ts regex patterns no longer use /g flag with test()
• Prevents stateful matching bugs on consecutive calls

Code Cleanup:

• Unused exports removed from:
  • mimeTypes.ts
  • validation/schemas.ts
  • utils/cors.ts
  • utils/pathSecurity.ts
• Reduces module surface area and maintenance burden

Download Validation:

• GameDataDownloader.getFilename() validates timestamps
• Rejects NaN timestamps to prevent corrupted filenames

Resource Leak Prevention:

• GameDataDownloader destroys response stream on size limit
• Prevents resource leaks from oversized downloads

DRY Principle:

• GameDataService uses GameDataDownloader.getFilename() instead of duplicating logic
• Centralizes filename generation

6. docs/05-game-service/configuration.md

Updated "CGI Configuration (via proxySettings.json)" section with information about PreferencesService:

• Documents singleton pattern for reading preferences.json
• Explains re-initialization warning logging
• Helps identify configuration issues during development
• Examples of warning messages logged

Impact

These documentation updates ensure that:

1. Code clarity: All improvements are documented for future maintainers
2. Knowledge preservation: Medium and low severity fixes are recorded
3. Developer onboarding: New team members understand recent improvements
4. Architecture understanding: Readers see complete picture of design
5. Best practices: Documents explain why each improvement matters

Markdown Formatting

All updated files follow consistent markdown formatting with:

• Clear section headers
• Code examples where relevant
• Bullet points for key improvements
• Context about why changes were made
• Benefits and implications explained