Asset Fingerprinting

Automatically appends a content hash (?v=xxxxxxxx) to the theme's CSS / JS / image / font references, enabling "permanent strong caching + automatic invalidation". Enabled by default.

How it works

Before a change: <link rel="stylesheet" href="/css/layout.css?v=03a4efc4">
After an edit:   <link rel="stylesheet" href="/css/layout.css?v=91b2d7f0">  ← hash changes, URL changes

1. At build time, a SHA-256 hash is computed from the source file contents (for CSS, the hash covers the .styl sources and all their @import dependencies; for fonts, the generated output)
2. The hash is appended to every local asset reference URL in the pages
3. With fingerprinted URLs, browsers can safely enable one-year strong caching
4. Any source change → hash change → URL change → cache invalidated automatically, returning visitors get fresh assets

Configuration

fingerprint:
  enable: true   # enabled by default; set false to restore original URLs

Coverage

Location	Behavior
src / href attributes in HTML	✅ ?v= appended
url() inside inline <style> (e.g. @font-face fonts)	✅ ?v= appended
Font preload links	✅ ?v= appended
hexo server local preview	✅ also applied, handy for debugging

Not touched: external URLs (http://, https://), pure anchors (#), relative paths.

Notes

• The hash is based on file contents, not the version number — a single character change alters it
• Works with the PWA Service Worker: when a fingerprinted asset changes, the SW cache key updates too, so visitors never get stuck on a stale page
• URLs that already have a query string only get their v parameter updated — no ?v=a?v=b stacking
• Assets outside the theme (scripts you inject yourself, images inside posts) are unaffected