R/download.R

In JesJehle/earthEngineGrabR: Simplify the acquisition of remote sensing data

#' wait_for_file_on_drive
#' @param filename name of the file to scan drive for
#' @noRd
wait_for_file_on_drive <- function(filename, verbose = T) {
  test <- try(googledrive::drive_find(filename, verbose = F), silent = T)

  while (nrow(test) < 1) {
    Sys.sleep(1)
    if (verbose) cat(".")
    test <- try(googledrive::drive_find(filename, verbose = F), silent = T)
  }
  return(T)
}



#' download_data
#' @param ee_response Output of the request_data function.
#' @param clear If the file should be removed from Google Drive after the download.
#' @noRd
#' @return nothing
download_data <- function(ee_response,
                          clear = T,
                          verbose = T,
                          temp_path) {
  for (i in seq_along(ee_response)) {
    if (i == 1) {
      if (verbose) {
        cat("\nwaiting for Earth Engine", "\n")
      }
    }

    path_full <- file.path(temp_path, ee_response[i])

    wait_for_file_on_drive(ee_response[i])

    if (verbose == T) {
      cat("\n")
    }
    googledrive::drive_download(
      file = ee_response[i],
      path = path_full,
      overwrite = T,
      verbose = F
    )

    if (verbose) {
      cat(paste0("\ndownload: ", get_name_from_path(ee_response[i]), "\n"))
    }
    # delete folder
    if (clear) {
      googledrive::drive_rm(ee_response[i], verbose = F)
    }
  }
}



#' import data
#' @param productList List of data files produced in the ee_grab function
#' @param verbose If true, messages reporting the processing state are printed.
#' @return nothing
#' @noRd
import_data <- function(product_list, verbose = T, temp_path) {

  # product_list <- unlist(productList)

  downloads <- list.files(temp_path)
  downloads_clean <- grep("geojson", downloads, value = T)

  while (sum(product_list %in% downloads_clean) != length(product_list)) {
    if (verbose) cat("\nwaiting for Earth Engine", "\n")
    if (verbose) cat(".")
    Sys.sleep(2)
    downloads <- list.files(temp_path)
    downloads_clean <- grep("geojson", downloads, value = T)
  }

  ## import data
  if (verbose) cat("\nimport: finished", "\n")
  join <- sf::st_read(file.path(temp_path, downloads_clean[1]), quiet = TRUE)
  file.remove(file.path(temp_path, downloads_clean[1]))
  if (length(downloads_clean) > 1) {
    for (i in 2:length(downloads_clean)) {
      data <- sf::st_read(file.path(temp_path, downloads_clean[i]), quiet = TRUE)
      file.path(temp_path, downloads_clean[i])
      data_no_geom <- sf::st_set_geometry(data, NULL)
      join <- merge(join, data_no_geom)
    }
  }
  return(join)
  # if(clean) unlink(temp_path, recursive = T)
}