propshaft.cr

A port of propshaft 1.3.2 — the asset pipeline compiler (pass-through model, no transpilation) — for CRails.

What it does:

• compiles assets from the load path (app/assets/*, vendor/…) into public/assets with digest names (landing.css → landing-7f665b1b.css; the digest is SHA1 of the content plus its references, 8 hex characters);
• rewrites url(...) in CSS and RAILS_ASSET_URL("...") in JS to /assets/<name>-<digest>.<ext>, and sourceMappingURL to the digested .map path;
• writes public/assets/.manifest.json: {"<logical>":{"digested_path":"…","integrity":null}};
• precompresses with .gz/.br siblings (a CRails extension; static.cr serves them by Accept-Encoding);
• clean/clobber/reveal.

Serving is handled by railties_cr's CRails::Middleware::Static (a port of Propshaft::Server): in development it resolves against the load path, in production it serves digest files from public/assets. View-level path resolution lives in CRails::PropshaftHelper (compute_asset_path via the manifest/load path).

Specs

Oracle-first (see AGENTS.md): a snapshot taken from the real gem — oracle/propshaft_expected.yml (44 cases) — with a mirror in spec/propshaft_spec.cr. The reverse check has the gem verify the port's output byte for byte (oracle/verify_propshaft.rb).

crystal spec                              # oracle mirror
# reverse (ruby 3.4 + propshaft 1.3.2 in GEM_HOME):
GEM_HOME=… ruby oracle/propshaft_cases.rb > /tmp/x.yml   # snapshot
crystal run spec/reverse_runner.cr -- /tmp/out            # port output
ruby oracle/verify_propshaft.rb oracle/reverse_fixture /tmp/out

Deviations from the gem are documented in PLAN.md.