Skill: anderskev/urlsession-code-review (version 1.2.1)

--- name: urlsession-code-review description: Reviews URLSession networking code for iOS/macOS. Covers async/await patterns, request building, error handling, caching, and background sessions. triggers: - URLSession - URLRequest - URLCache - URLError - iOS networking --- # URLSession Code Review ## Quick Reference | Topic | Reference | |-------|-----------| | Async/Await | [async-networking.md](references/async-networking.md) | | Requests | [request-building.md](references/request-building.md) | | Errors | [error-handling.md](references/error-handling.md) | | Caching | [caching.md](references/caching.md) | ## Review Checklist ### Response Validation - [ ] HTTP status codes validated - URLSession does NOT throw on 404/500 - [ ] Response cast to HTTPURLResponse before checking status - [ ] Both transport errors (URLError) and HTTP errors handled ### Memory & Resources - [ ] Downloaded files moved/deleted (async API doesn't auto-delete) - [ ] Sessions with delegates call `finishTasksAndInvalidate()` - [ ] Long-running tasks use `[weak self]` - [ ] Stored Task references cancelled when appropriate ### Configuration - [ ] `timeoutIntervalForResource` set (default is 7 days!) - [ ] URLCache sized adequately (default 512KB too small) - [ ] Sessions reused for connection pooling ### Background Sessions - [ ] Unique identifier (especially with app extensions) - [ ] File-based uploads (not data-based) - [ ] Delegate methods used (not completion handlers) ### Security - [ ] No hardcoded secrets (use Keychain) - [ ] Header values sanitized for CRLF injection - [ ] Query params via URLComponents (not string concat) ## Hard gates (before reporting findings) Complete in order. Do not advance while a prior gate is open. 1. **Scope** — **Pass:** You name at least one file under review where `URLSession`, `URLRequest`, `HTTPURLResponse` / `URLResponse`, `URLCache`, or `URLError` appears on a networking path. If none apply, stop with “out of scope.” 2. **HTTP vs transport** — **Pass:** Before claiming missing HTTP status handling or “404 treated as success,” you cite `file:line` for the completion/async/`for await` path that receives `response` and state whether `HTTPURLResponse` is cast and `statusCode` is checked (or cite the helper that does). If you cannot see the handler, say **unknown** and ask for it—do not assume. 3. **Session lifecycle** — **Pass:** For a custom `URLSession` with a delegate, you cite `finishTasksAndInvalidate()` or the documented long-lived/singleton pattern you rely on; for `.shared`, say so if the finding depends on configuration. Skip if only ad hoc `URLSession.shared` one-shots with no delegate issues. 4. **Background or file transfer (if applicable)** — **Pass:** If `URLSessionConfiguration.background`, `downloadTask`, or app-extension–scoped sessions appear, findings cite identifier uniqueness, delegate vs completion-handler usage, or file URLs as required. If none of those APIs appear, mark **N/A** and continue. 5. **Severity and checklist** — **Pass:** Every **Critical** item includes `file:line` and names which **Review Checklist** subsection it violates (e.g. Response Validation, Background Sessions). Lower-severity items still name the file(s) they are drawn from. ## Output Format ```markdown ### Critical 1. [FILE:LINE] Missing HTTP status validation - Issue: 404/500 responses not treated as errors - Fix: Check `httpResponse.statusCode` is 200-299 ```


Security scan verdicts — ClawScan: clean | static analysis: clean | VirusTotal: clean | SkillSpector: clean (LOW)