Declare a post-download processor

A processor turns one verified path into another path: unpacking an archive, or preparing a package-specific layout. It carries an id so the processed result gets its own cache slot and its own provenance, rather than being confused with the raw artefact it came from.

Usage

processor(id, fn)

Arguments

id

Short stable identifier for this transformation, for example "unzip" or "unzip-v2". Changing the transformation means changing the id, which invalidates previously processed copies.

fn

A function (input, output_dir) returning a path inside output_dir.

Value

An object of class getaca_processor.

Details

getaca knows nothing about file formats. It never reads data.

Examples

unzipper <- processor("unzip", function(input, output_dir) {
  utils::unzip(input, exdir = output_dir)
  output_dir
})