Conditional breakpoint rules — match by headers, status, body, not just URL

[phaser]

Description

Shmoxy's breakpoint rules only match on method + URL substring. Users cannot set breakpoints based on headers, body content, status codes, or other request/response attributes.

What Competitors Offer

Burp Suite — Intercept rules support matching on: URL, host, method, request headers, request body, response headers, response body, status code, MIME type, file extension. Rules combine with AND/OR logic.

Charles Proxy — Breakpoints support host, path, and query matching. Also supports response breakpoints (not just request).

OWASP ZAP — Breakpoint conditions on URL, method, and custom criteria via scripts.

Current State in Shmoxy

• BreakpointRule has Method (nullable) and UrlPattern (substring match)
• No regex (No regex support in breakpoint URL patterns — only substring matching #251 tracks this separately)
• No header, body, or status code matching
• No response breakpoints (No response body interception — breakpoints only work on requests #235 tracks this separately)
• No AND/OR composition of multiple conditions

Suggested Approach

1. Extend BreakpointRule with additional match criteria: header name/value, body content pattern, content-type
2. Add a condition builder UI (not just method + URL fields)
3. Support AND composition of criteria (all must match)
4. Keep the simple "break on this URL" shortcut for quick use

Priority

Medium — The current simple matching covers common cases, but power users need more precise control to avoid breaking on every request to a busy host.