Dc is a package for the R statistical language that
downloads files from the web in such a way as to permit caching by filename.
This is accomplished by constructing filenames based on the web queries used to
download the data. For example, when the dc.topo function retrieves a
topographic matrix for a particular region, it embeds the location and
resolution in name of the file it downloads, so that a second call to dc.topo
with the same parameters yields the existing filename, without causing a second
download.
Development of this package takes place on https://github.com/dankelley/dc.