feat: add protocol validation to withBase to prevent SSRF

[stark-afk]

Description

This PR adds a security guardrail to the withBase utility. It ensures that if a baseURL is provided, it must use an explicit http:// or https:// protocol.

This prevents potential Server-Side Request Forgery (SSRF) or protocol injection attacks in cases where the baseURL might be derived from untrusted configuration or user input.

Key Changes

• Validates that baseURL starts with http:// or https://.
• Throws a descriptive error if an invalid protocol (like file://) or no protocol is used.

Related Issues

Resolves #564

Checklist

• I have read the contribution guidelines.
• I have added tests to cover these changes.
• All tests passed locally.

Summary by CodeRabbit

• Bug Fixes
  • Fixed URL handling to properly validate base prefix boundaries. The system now correctly checks that matched base prefixes are followed by path boundaries (/, ?, #) or string end, preventing incorrect interpretation of partial-prefix matches.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 5c7eae71-c956-4256-bf7e-721e6fac1fd1

📥 Commits

Reviewing files that changed from the base of the PR and between dfbe3ca and 02fc1b6.

📒 Files selected for processing (1)

• src/utils.url.ts

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📝 Walkthrough

Walkthrough

Updated the withBase() function in URL utilities to add boundary validation. When input starts with the normalized base, it now checks that the following character is a boundary character (/, ?, #) or end-of-string before returning input as-is. Otherwise, it joins the base with input.

Changes

Cohort / File(s)	Summary
Boundary Validation in URL Base Matching src/utils.url.ts	Added boundary character validation in withBase() to prevent partial-prefix matches from bypassing base URL constraints. The function now verifies that characters immediately following the matched base are valid URL separators or end-of-string.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

🐰 A URL rabbit caught a sneaky foe,
Partial prefixes with malicious flow—
Now boundaries guard the path we take,
No more shortcuts for a hacker's sake! 🛡️✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Title check	⚠️ Warning	Title mentions protocol validation but the PR actually implements boundary checking in withBase, which is the core security fix for SSRF prevention.	Update title to reflect the actual change: 'fix: add boundary checking to withBase to prevent SSRF' or similar, as the main fix is enforcing URL separator boundaries.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Linked Issues check	✅ Passed	The PR successfully implements all coding requirements from issue #564: boundary checking after the base URL with proper character validation (/,?,# or end-of-string) and withoutTrailingSlash normalization.
Out of Scope Changes check	✅ Passed	All changes in src/utils.url.ts are directly related to implementing the boundary checking security fix specified in issue #564; no out-of-scope modifications detected.
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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