Download several zip files automatically

I recently found out that a bunch of new past climate scenarios were made available on WorldClim, at least for past climate. While there may be more efficient ways to do this, here’s the R function I wrote to download several of them automatically based on the URLs (link locations) of the .zip files:

downloadZips <- function(zip.urls, zip.names = NULL, dir.name = NULL, unzip = FALSE) {
# zip.names: names to give the downloaded zip files (if different from the original ones)
# dir.name: name of the directory folder in which to store the downloaded files
# unzip: logical, whether or not to unzip the files after downloading
  stopifnot(is.null(zip.names) | length(zip.names) == length(zip.urls))
  if (!is.null(dir.name)) {
    dir.create(dir.name)
    setwd(dir.name)
    on.exit(setwd("../"))
  }
  if (is.null(zip.names))  zip.names <- tools::file_path_sans_ext(basename(zip.urls))
  for (z in 1:length(zip.urls)) {
    message("\nDownloading zip ", z, " of ", length(zip.urls), " (", zip.names[z], ")...\n")
    zip.file <- paste(zip.names[z], "zip", sep = ".")
    download.file(zip.urls[z], zip.file)
    if (unzip) {
      dir.create(zip.names[z])
      message("Unzipping file to folder '", zip.names[z], "'...")
      unzip(zip.file, exdir = zip.names[z])
    }  # end if unzip
  }  # end for z
  message("Finished!")
}  # end downloadZips function

Usage examples (mind that these large files take quite a while to download):

# LGM:
downloadZips(zip.urls = c("http://biogeo.ucdavis.edu/data/climate/cmip5/lgm/cclgmbi_2-5m.zip", "http://biogeo.ucdavis.edu/data/climate/cmip5/lgm/mrlgmbi_2-5m.zip", "http://biogeo.ucdavis.edu/data/climate/cmip5/lgm/melgmbi_2-5m.zip"), zip.names = c("CCSM4", "MIROC_ESM", "MPI_ESM_P"), dir.name = "LGM")
 
# Mid Holocene:
downloadZips(zip.urls = c("http://biogeo.ucdavis.edu/data/climate/cmip5/mid/bcmidbi_2-5m.zip", "http://biogeo.ucdavis.edu/data/climate/cmip5/mid/ccmidbi_2-5m.zip", "http://biogeo.ucdavis.edu/data/climate/cmip5/mid/cnmidbi_2-5m.zip", "http://biogeo.ucdavis.edu/data/climate/cmip5/mid/hgmidbi_2-5m.zip", "http://biogeo.ucdavis.edu/data/climate/cmip5/mid/hemidbi_2-5m.zip", "http://biogeo.ucdavis.edu/data/climate/cmip5/mid/ipmidbi_2-5m.zip", "http://biogeo.ucdavis.edu/data/climate/cmip5/mid/mrmidbi_2-5m.zip", "http://biogeo.ucdavis.edu/data/climate/cmip5/mid/memidbi_2-5m.zip", "http://biogeo.ucdavis.edu/data/climate/cmip5/mid/mgmidbi_2-5m.zip"), zip.names = c("BCC_CSM1_1", "CCSM4", "CNRM_CM5", "HadGEM2_CC", "HadGEM2_ES", "IPSL_CM5A_LR", "MIROC_ESM", "MPI_ESM_P", "MRI_CGCM3"), dir.name = "MidHol")
 
# Last Inter-Glacial:
downloadZips(zip.urls = "http://biogeo.ucdavis.edu/data/climate/worldclim/1_4/grid/pst/lig/lig_30s_bio.zip", zip.names = "LIG_30s", dir.name = "LIG")

[presented with Pretty R]