XML
Using XML Namespaces for Extensions Without the Chaos
Let partners add their own data to your XML format safely by giving each extension its own namespace, with a reader that ignores what it does not own.
6 min read
Tag
how-to
590 posts
CSV
Turning Currency Strings Into Numbers in a CSV Exactly
Parse $1,234.50, (12.50), 1.234,50 € and 7,00 into exact Decimals, find the cases where stripping symbols is wrong, and spot a column that mixes currencies.
8 min read
Excel
Password Protected Excel Files and Scripts That Read Them
Read password protected Excel files from a script with msoffcrypto-tool, tell file encryption from sheet protection, and keep passwords out of code and logs.
7 min read
XML
Mixed Content in XML and Why It Hurts Parsing and Mapping
Text and elements side by side look natural in documents and break data models. How ElementTree and lxml expose text and tail, and what to do instead.
6 min read
YAML
Secrets Accidentally Committed in YAML Files and the Cleanup
What to do when a token lands in a values or config YAML: removing it from the file leaves it in history, gitleaks finds it, and rotation is the real fix.
6 min read
JSON
Using DynamoDB Maps and Lists as JSON Documents Safely
Store JSON in DynamoDB map and list attributes, update nested paths in place and avoid float, reserved-word and size errors, tested on DynamoDB Local.
7 min read
Excel
Zip Bombs and Oversized XLSX Uploads and Limits That Work
Stop zip bombs and oversized xlsx uploads with limits on file size, entry count, expansion ratio and rows, enforced before parsing and sized from real files.
7 min read
XML
Embedding Binary Data in XML With Base64 and When Not To
XML cannot hold raw bytes. Base64 adds 33 percent, hex adds 100 percent, and both cost memory. Measured sizes, the schema type, and the alternatives.
6 min read
CSV
Trimming Whitespace in Every Field of a CSV Safely
Trim padded CSV fields with pandas, the csv module, DuckDB and qsv, and see why strip() misses the zero-width space that still breaks an email match.
9 min read
Excel
Opening Untrusted Excel Files Safely in a Pipeline
Open untrusted Excel files in a sandboxed worker with no network, memory and time limits, a read-only parser and no desktop Excel, then load results as data.
7 min read
JSON
Storing JSON in ClickHouse and Querying Its Fields Fast
Store JSON in ClickHouse as a String with JSONExtract functions or as the native JSON type, with size and speed measured on 200,000 documents.
7 min read
Editor's pick
CSVGuide
A Repeatable Way to Clean a Messy CSV File With Python
A cleaning pipeline that never edits the raw file, counts rows at every step and keeps rejects: 200,000 rows in 3.85 s, identical output twice.
25 min read