Lib.rs

Like include_dir, but specialized for serving a directory as a web application.

Differences from include_dir

• Only files are included. Directories are excluded.
• Paths must be valid UTF-8 without nul characters.
• Path lookup is optimized (using litemap).
• File metadata useful for HTTP caching are computed at build time.

HTTP Caching Headers

CWebFile fields provide values which can be used for HTTP cache-related response headers:

• ETag is the base32-encoded rapidhash of the file contents.
• Last-Modified is read from the filesystem metadata.
• Cache-Control: immutable can be set if the path starts with assets/.

Immutable Assets

The assumption that files under assets/ should be immutable comes from the default settings of Vite. Most modern web apps use Vite as a bundler. Its default settings implement the "cache-busting" pattern, meaning that static resources will be written to a subpath of assets/ and a hash will be appended to file names before the file extension. This pattern makes it possible to cache entire static web applications on the client web browser.