Computation of handleStaticFile fpath serves the file at fpath on the filesystem. The Resource must be in the /Examining Request state before the computation. It will be in the Done/ state after the computation.

If you just want to place a static file on the ResTree, you had better use staticFile instead of this.

Computation of handleStaticDir dir maps all files in dir and its subdirectories on the filesystem to the ResTree. The Resource must be in the /Examining Request state before the computation. It will be in the Done/ state after the computation.

If you just want to place a static directory tree on the ResTree, you had better use staticDir instead of this.

Computation of generateETagFromFile fpath generates a strong entity tag from a file. The file doesn't necessarily have to be a regular file; it may be a FIFO or a device file. The tag is made of inode ID, size and modification time.

Note that the tag is not strictly strong because the file could be modified twice at a second without changing inode ID or size, but it's not really possible to generate a strict strong ETag from a file since we don't want to simply grab the entire file and use it as an ETag. It is indeed possible to hash it with SHA-1 or MD5 to increase strictness, but it's too inefficient if the file is really large (say, 1 TiB).