Building a CSV generator in PHP

A CSV generator must produce a file the recipient can interpret correctly. An agreed schema and preserved values matter more than the filename extension.

Agree the format

Specify columns, order, encoding, separator, empty values and line endings. Treat identifiers according to their meaning so leading zeros survive.

Use a CSV writer

PHP's fputcsv writes an array of fields to a stream. Set format parameters explicitly and check write failure. Do not join arbitrary values with commas: they may contain quotes or newlines.

Documentation: PHP Manual — fputcsv.

Test difficult values

Include accented characters, commas, quotes, newlines, empty data and long identifiers. For spreadsheet use, consider values that may be interpreted as formulas. Match protection to the recipient.

Control access and size

Export only necessary fields for authorised users. Process large datasets in stages. Never present an incomplete file as finished.

Accept at the destination

Read the export back and compare record counts and values. Then test the target importer. Schema versions and reports reveal changing requirements.