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build_versioned_font_css.php

Path: build/build_versioned_font_css.php | Language: PHP | Lines: ~40

Adds cache-busting version parameters to font file URLs in generated CSS.

Overview​

This script takes the CSS files produced by build_font_css.php and transforms them into versioned variants by appending modification timestamps to font file URLs. This enables aggressive browser caching while ensuring users always receive updated fonts when files change.

The versioning strategy uses query parameters (?v=timestamp) based on the actual modification time of each font file on disk. This approach is superior to build-time versioning because it accurately reflects when individual font files were updated, not when the CSS was regenerated.

The script is intentionally simple and focused: it performs a regex replacement on font URLs, delegates actual timestamp retrieval to filemtime(), and produces drop-in replacements for the original CSS files.

Key Functions/Variables​

VersionAssetURL($m) Callback function for preg_replace_callback that receives a regex match array and returns the versioned URL. It extracts the file path, retrieves the modification timestamp using filemtime(), and constructs a versioned URL with ?v={timestamp} appended.

Global variables:

  • $static_root: Root directory path for static assets, used to construct absolute paths for filemtime() calls
  • $font_files: Array of base filenames to process (['fonts', 'initial-fonts'])

Input/Output​

Inputs:

  • /css/fonts-GENERATED.css - Generated font CSS from build_font_css.php
  • /css/initial-fonts-GENERATED.css - Initial subset font CSS from build_font_css.php
  • /static/* - Font files on disk (for filemtime() calls)

Outputs:

  • /css/fonts-VERSIONED.css - Font CSS with versioned URLs
  • /css/initial-fonts-VERSIONED.css - Initial font CSS with versioned URLs

Usage​

Invoked by sync.sh after build_font_css.php completes:

php build/build_versioned_font_css.php

The versioned CSS files are then used as the canonical font stylesheets referenced by HTML templates and build processes.

See Also​