Description

Unix socket connections are inherently local—only processes on the same host can connect via Unix domain sockets. However, IsFromLocal() returned false for them because fasthttp.RemoteIP() returns 0.0.0.0 for Unix sockets, and 0.0.0.0.IsLoopback() returns false.

This PR adds explicit *net.UnixAddr handling to IsFromLocal(), consistent with IsProxyTrusted().

Changes introduced

• req.go: Added type check for *net.UnixAddr that returns true before the IP loopback check, with properly formatted inline comment
• ctx_test.go: Added test case verifying Unix socket connections return true, plus added defer app.ReleaseCtx(c) to all test blocks to prevent context leaks

// IsFromLocal will return true if request came from local.
func (r *DefaultReq) IsFromLocal() bool {
	// Unix sockets are inherently local - only processes on the same host can connect.
	remoteAddr := r.c.fasthttp.RemoteAddr()
	if _, ok := remoteAddr.(*net.UnixAddr); ok {
		return true
	}

	if ip := r.c.fasthttp.RemoteIP(); ip != nil {
		return ip.IsLoopback()
	}
	return false
}

• Benchmarks: No performance impact—added early return path for Unix sockets
• Documentation Update: N/A—behavioral fix, no API changes
• Changelog/What's New: Fixed IsFromLocal() returning false for Unix socket connections
• Migration Guide: N/A—transparent fix
• API Alignment with Express: N/A
• API Longevity: No API changes
• Examples: N/A

Type of change

• Code consistency (non-breaking change which improves code reliability and robustness)

Checklist

• Followed the inspiration of the Express.js framework for new functionalities, making them similar in usage.
• Conducted a self-review of the code and provided comments for complex or critical parts.
• Updated the documentation in the /docs/ directory for Fiber's documentation.
• Added or updated unit tests to validate the effectiveness of the changes or new features.
• Ensured that new and existing unit tests pass locally with the changes.
• Verified that any new dependencies are essential and have been agreed upon by the maintainers/community.
• Aimed for optimal performance with minimal allocations in the new code.
• Provided benchmarks for the new code to analyze and improve upon.

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