• Extract session exchange logic into separate handleSessionExchange function
• Extract session verification logic into verifySession function
• Add helper functions for URL building, header extraction, and query parameter extraction
• Improve X-Forwarded-For header parsing with better validation and error handling
• Add constants for magic strings (headerSetCookie, msgInternalServerError)
• Enhance error handling throughout the codebase
• Fix session validation logic flow and improve code readability

Copilot:
This pull request refactors and improves the Badger middleware in main.go for session handling and verification. The changes focus on code modularization, improved error handling, and more robust client IP extraction. The main logic for session exchange and verification is split into dedicated methods, with utility helpers added for extracting request data and handling errors.

Session handling and middleware flow improvements:

• Refactored the main ServeHTTP method to delegate session exchange and verification to separate helper methods, improving readability and maintainability. The session exchange logic is now handled in handleSessionExchange, and session verification is handled in verifySession. ([[1]](https://github.com/onno204/badger/pull/1/files#diff-2873f79a86c0d8b3335cd7731b0ecf7dd4301eb19a82ef7a1cba7589b5252261L83-R108), [[2]](https://github.com/onno204/badger/pull/1/files#diff-2873f79a86c0d8b3335cd7731b0ecf7dd4301eb19a82ef7a1cba7589b5252261L96-L158))
• Added a new buildOriginalRequestURL helper to consistently reconstruct the original request URL after modifying query parameters. ([main.goL213-R327](https://github.com/onno204/badger/pull/1/files#diff-2873f79a86c0d8b3335cd7731b0ecf7dd4301eb19a82ef7a1cba7589b5252261L213-R327))

Error handling enhancements:

• Centralized internal server error responses in a new internalServerError function, replacing repeated inline error handling with a single call. ([[1]](https://github.com/onno204/badger/pull/1/files#diff-2873f79a86c0d8b3335cd7731b0ecf7dd4301eb19a82ef7a1cba7589b5252261L96-L158), [[2]](https://github.com/onno204/badger/pull/1/files#diff-2873f79a86c0d8b3335cd7731b0ecf7dd4301eb19a82ef7a1cba7589b5252261L168-R200), [[3]](https://github.com/onno204/badger/pull/1/files#diff-2873f79a86c0d8b3335cd7731b0ecf7dd4301eb19a82ef7a1cba7589b5252261L213-R327))
• Improved unauthorized response handling by returning early when session verification fails, rather than proceeding through the rest of the handler. ([main.goL213-R327](https://github.com/onno204/badger/pull/1/files#diff-2873f79a86c0d8b3335cd7731b0ecf7dd4301eb19a82ef7a1cba7589b5252261L213-R327))

Request data extraction utilities:

• Added extractHeaders and extractQueryParams helpers to extract relevant request headers and query parameters, simplifying the main logic and making data handling more explicit. ([main.goL213-R327](https://github.com/onno204/badger/pull/1/files#diff-2873f79a86c0d8b3335cd7731b0ecf7dd4301eb19a82ef7a1cba7589b5252261L213-R327))
• Refactored extractCookies to its own method for clarity and consistency. ([main.goL213-R327](https://github.com/onno204/badger/pull/1/files#diff-2873f79a86c0d8b3335cd7731b0ecf7dd4301eb19a82ef7a1cba7589b5252261L213-R327))

Client IP extraction improvements:

• Enhanced the getClientIP method to robustly handle various headers (including X-Forwarded-For) and provide clear fallback logic, with improved security comments and validation. ([main.goL213-R327](https://github.com/onno204/badger/pull/1/files#diff-2873f79a86c0d8b3335cd7731b0ecf7dd4301eb19a82ef7a1cba7589b5252261L213-R327))

Constants and code style:

• Introduced constants for common header names and error messages to avoid repetition and potential typos. ([main.goR10-R18](https://github.com/onno204/badger/pull/1/files#diff-2873f79a86c0d8b3335cd7731b0ecf7dd4301eb19a82ef7a1cba7589b5252261R10-R18))

These changes collectively improve the modularity, clarity, and reliability of the session middleware.