R/download_models.R

In r4ss/r4ss: R Code for Stock Synthesis

#' Download SS3 test models
#'
#' Download and unzip the models folder stored on GitHub within the
#' nmfs-ost/ss3-test-models repository.
#' @param dir A file path where the downloaded `"models"` subfolder will be written to.
#' @param branch A string specifying the desired branch of
#' [nmfs-ost/ss3-test-models repository](https://github.com/nmfs-ost/ss3-test-models#test-models)
#' that you want to download. The default is `"main"`, which is the
#' stable/default branch.
#' @template overwrite
#' @return Invisibly return a logical revealing whether the files were copied
#'  (TRUE) or not (FALSE). This function is used for its side effects of
#'  downloading SS3 test models.
#' @examples
#' download_models(dir = getwd())
#' model_name <- list.files("models") # see the model names
#' # remove files
#' unlink(file.path("models"), recursive = TRUE)
#' @author Kathryn Doering
#' @references [nmfs-ost/ss3-test-models repository](https://github.com/nmfs-ost/ss3-test-models#test-models)
#' @export
download_models <- function(dir = file.path("inst", "extdata"),
                            branch = "main",
                            overwrite = FALSE) {
  # checks
  if (!dir.exists(dir)) {
    dir.create(dir, recursive = TRUE)
  }
  zip_file_path <- file.path(dir, "test-models.zip")
  result <- tryCatch(
    utils::download.file(
      url = paste0(
        "https://github.com/nmfs-ost/ss3-test-models/archive/",
        branch,
        ".zip"
      ),
      destfile = zip_file_path
    ),
    error = function(e) {
      stop(
        "The test-models zip file could not be downloaded.",
        " Does the branch (", branch, ") exist?",
        call. = FALSE
      )
    }
  )
  list_files <- utils::unzip(list = TRUE, zipfile = zip_file_path)
  save_files <- list_files[grep("/models/", list_files[["Name"]], fixed = TRUE), ]
  utils::unzip(
    zipfile = zip_file_path, files = save_files[["Name"]],
    exdir = dir
  )
  if (dir.exists(file.path(dir, "models")) & overwrite == FALSE) {
    warning(
      "The model directory ", file.path(dir, "models"), " already exists ",
      "\nand overwrite is FALSE. So, no new files will be written."
    )
  }
  dir.create(file.path(dir, "models"), showWarnings = FALSE)
  copy_status <- file.copy(
    from = file.path(dir, paste0("ss3-test-models-", branch), "models"),
    to = file.path(dir), recursive = TRUE, overwrite = overwrite
  )
  # clean up
  unlink(zip_file_path)
  unlink(file.path(dir, paste0("ss3-test-models-", branch)),
    recursive = TRUE
  )
  invisible(copy_status)
}