Sprockets is a Rack-based asset packaging library that serves as the core of the Rails asset pipeline. It compiles, concatenates, minifies, fingerprints, and serves JavaScript, CSS, images, fonts, and other static web assets. The architecture is modular: an `Environment` object manages load paths, processors, transformers, compressors, and exporters; a `Manifest` compiles assets to disk with digest filenames; and a `Server` provides a Rack endpoint for development. Assets flow through a pipeline of preprocessors (e.g., ERB, CoffeeScript, Babel), transformers (MIME type conversions), postprocessors, bundle processors (concatenation), and optionally compressors and exporters (gzip, file write). The library supports source maps, caching with dependency tracking, and extensible registration of custom processors, transformers, and compressors. It is a mature, well-architected library with clean abstractions and high reusability, though it carries some legacy components (e.g., YUI compressor, Sass importer) and optional external gem dependencies.
Parklife is a Ruby library and CLI tool that converts Rack-based web applications (like Rails or Sinatra) into static HTML sites suitable for deployment on static hosting platforms (Netlify, Vercel, GitHub Pages, S3, etc.). It works by crawling the application's routes starting from defined entry points, making HTTP requests to each endpoint via Rack::Test, and saving the responses as appropriate files in a build directory. The library intelligently handles different HTTP response types through a responder pattern (200=OK, 304=NotModified, 404=NotFound, etc.), supports automatic link discovery and crawling from HTML responses, and provides flexible configuration for output formatting, caching via ETags, and 404 handling. Key features include route crawling with depth control, intelligent file naming logic (HTML vs other content types), and multiple reporter formats (progress dots, detailed logs, or silent).