go-webdav is a Go library implementing WebDAV (RFC 4918), CalDAV (RFC 4791), and CardDAV (RFC 6352) protocols. It provides client and server implementations for these protocols, with a clear separation between the HTTP handling layer and storage backends via a FileSystem interface. The library includes a command-line tool to run a WebDAV server serving a local directory. The architecture is modular, with core WebDAV functionality in the 'webdav' package, CalDAV and CardDaV extensions in their respective packages, and low-level HTTP/XML handling in the 'internal' package. The library depends on go-ical and go-vcard for calendar and contact data processing.