R/bulk_dl.R

In dylan-turner25/rfema: Access the openFEMA API

#' Bulk download full open FEMA data sets as .csv files
#'
#' For large data requests, it can sometimes be more practical (and quicker)
#' to download and work with the entire data set. This function provides an
#' easy way to download any of FEMA's data sets in its entirety and save it
#' locally as a csv file.
#'
#' @param data_set A character string indicating the name of the data set
#' to download
#' @param output_dir An optional character string indicating the
#' directory (defaults to working directory)
#' @param file_name An optional character string indicating the file
#' name (defaults to data set name with time stamp)
#' @param size_warning A logical indicating whether to issue a warning
#' before proceeding with downloading a large file (default is TRUE)
#' @return Returns a downloaded csv file of the data set to the
#' specified output directory.
#' @importFrom utils download.file
#' @export
#' @examples
#' \dontrun{
#' bulk_dl("femaregions") # download the file
#' }
#' \dontrun{
#' file.remove("FemaRegions.csv") # clean up directory after file downloads
#' }
bulk_dl <- function(data_set, output_dir = NULL, file_name = NULL, size_warning = TRUE) {

  # get info on all data sets fema offers
  ds <- fema_data_sets()

  # make sure data set is valid and uses the FEMA
  # consistent capitalization
  data_set <- unique(valid_dataset(data_set))

  # filter data sets to only those matching the name of the user
  # supplied data set
  ds <- ds[which(ds$name == data_set), ]

  # determine the most recent version of the data set
  latest_version <- max(as.numeric(ds$version))

  # filter data sets df to only the most recent version
  ds <- ds[which(as.numeric(ds$version) == latest_version), ]
  
  # get distribution info
  distribution <- data.frame(do.call(rbind,ds$distribution[[1]]))

  # get url for bulk download of csv file
  url <- as.character(distribution$accessURL[distribution$format == "csv"][[1]])

  if (is.null(output_dir)) {
    output_dir <- getwd()
  }
  if (is.null(file_name)) {
    file_name <- paste0(data_set, ".csv")
  }

  if (size_warning) {
    file_size <- distribution$datasetSize[which(distribution$format == "csv")][[1]]
    if (grepl("large", file_size)) {
      message(paste0(
        "FEMA indicates this file is: ",
        ds[which(ds$name == data_set), "distribution.datasetSize"],
        ". Continue with download?"
      ))

      user_response <- readline(prompt = " 1 - Yes, get that data!, 0 - No:")

      if (user_response != "1") {
        stop("Operation aborted by user.")
      }
    }
  }

  message(paste0("Downloading file to ", paste0(output_dir, "/", file_name)))

  utils::download.file(url,
    destfile = paste0(output_dir, "/", file_name),
    mode = "wb"
  )
}