CSV
Why a Hostile CSV Upload Can Hurt Your Application Server
A CSV upload needs no exploit to take a server down: compressed bombs, one huge field, an unclosed quote and wide files, each with the limit that stops it.
7 min read
Library
Everything you need to level up your coding skills.
JSONGuide
Pulling JSON From APIs Into a Database Reliably in Python
A working guide to loading JSON APIs into a database: raw pages, pagination, rate limits, upserts, cursors, shape checks and retries, with a tested loader.
17 min read
CSV
Doing a Three Way Merge of CSV Edits by Key and by Cell
Merge two people's edits of a CSV against a common base: git merge-file conflicts when both touch a row, merging by key and cell resolves different cells.
6 min read
CSV
Keeping a CSV Sorted So Diffs Stay Small in Version Control
Keep a CSV sorted by its key so a one-row change is a one-line diff: sort the body not the header, use byte order and numeric keys, and sort in the writer.
6 min read
CSV
Using git diff Sensibly on a CSV File With Word Diff
Make git diff readable for a CSV: word diff on commas, a textconv that aligns columns, a sorted file with one record per line and a trailing newline.
6 min read
CSV
Tailing and Following a CSV That Is Still Being Written
Follow a growing CSV with tail -f, skip the header, survive rotation with tail -F and read only complete lines, plus a Python follower and the buffering trap.
6 min read
CSV
Automating a Nightly CSV Export With cron and psql
A cron export that cannot publish a half-written file: lock, temporary name, row-count check, atomic rename. Real cron failed first, on the environment.
10 min read
JSONGuide
Using jq to Slice Up JSON in the Terminal Reliably
A tested guide to jq 1.8 for slicing JSON in the terminal: filters, streams, CSV, grouping, logs, safe variables, in-place edits and number quirks.
17 min read
YAMLGuide
Parsing YAML in Languages Other Than Python Compared
One YAML document parsed in Node, Go, Java, Ruby, PHP, Rust, C# and yq: types, dates, duplicate keys, strict modes, safety and parse speed, all measured.
17 min read
JSON
JSON parse and stringify Options You Probably Missed
The extra arguments of JSON.stringify and JSON.parse, tested in Node 24: toJSON, replacer arrays, indent limits, call order and exact numbers.
9 min read
JSONGuide
JSON in JavaScript and Node Done Carefully and Correctly
A tested guide to JSON in JavaScript and Node 24: what stringify drops, parse errors, big numbers, dates, circular data, cloning, files and large inputs.
20 min read
JSON
Reading JSON From an API With requests and Handling Errors
response.json() raised JSONDecodeError for an empty body, a 204, an HTML 502 and a BOM. Check status first, set a timeout and retry with a Session, as tested.
8 min read
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