This was basically a full mini-project crammed into one question.
Start by clarifying requirements and assumptions, then outline a modular design that separates concerns: HTTP client with auth, pagination, retry/backoff, and timeout handling; data parsing and validation; aggregation; and output serialization. Implement a minimal but runnable Python script using requests and standard libraries, walking through each component while discussing edge cases and complexity.
Pro tip: Before coding, explicitly state your assumptions (e.g., auth type, pagination style, rate limit headers) and ask clarifying questions—this shows you think about real-world integration challenges and avoids building the wrong thing.
Ask about auth method (API key, OAuth), pagination (cursor, offset, link headers), rate limit headers, expected data volume, and output format preferences. State your assumptions if details are missing.
Outline a structure: a client class handling auth, timeouts, retries with exponential backoff, and pagination; a parser that validates and extracts fields; an aggregator for top-k per category; and a serializer for CSV/JSON output.
Write code to fetch pages, handle 401/403 by refreshing tokens if needed, respect Retry-After headers, use timeouts, and catch network errors. Use a session for connection reuse.
Parse JSON, skip malformed records with logging, extract required fields (e.g., courier_id, status, timestamp, location), and handle missing or type-mismatched values gracefully.
Compute per-category counts or sums, find top-k items using a heap or sorting, and serialize both raw records and aggregates to CSV/JSON. Discuss time/space complexity.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.