R/getSetting.r

In strvalidator: Process Control and Validation of Forensic STR Kits

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# CHANGE LOG (last 20 changes)
# 22.02.2020: First version.

#' @title Get Settings.
#'
#' @description
#' Accepts a key string and returns the corresponding value.
#'
#' @details
#' Accepts a key string and returns the corresponding value from the settings.txt
#' file located within the package folders exdata sub folder.
#'
#' @param key character key for value to return.
#'
#' @export
#'
#' @importFrom data.table fread setkey
#'
#' @return character the retrieved value or NA if not found.
#'

getSetting <- function(key) {
  # Constants
  fileName <- "settings.txt" # Name of settings file with file extension.
  subFolder <- "extdata" # Sub folder in addition to package path.
  fileSep <- .Platform$file.sep # Platform dependent path separator.

  # Get package path. Could use getPackageName()?
  packagePath <- path.package("strvalidator", quiet = FALSE)

  # Create path to settings file.
  filePath <- paste(packagePath, subFolder, fileName, sep = fileSep)

  # If file exist.
  if (file.exists(filePath)) {
    # Read settings file.
    dtable <- fread(
      file = filePath, sep = "=",
      quote = "\"", header = FALSE,
      col.names = c("key", "value")
    )

    # Set key column.
    setkey(dtable, key = "key")

    # Get value.
    value <- dtable[key]$value
    message("Settings: ", key, "=", value)
  } else { # If file don't exist.

    # Show file not found message.
    message("File ", filePath, " not found. Returning NA.")

    # Set NA as return value.
    value <- NA
  }

  return(value)
}