R/is_rpi.R

In mnr/rpigpior: Provides R with Access to the Raspberry Pi

#' Provide information about the Operating System
#'
#' Returns TRUE if this code is running under Raspbian or return information about the operating system.
#'
#' @param onlyThis If no value is passed to onlyThis, is.rpi() will return a logical
#'
#' If 'onlyThis' is specified, 'is.rpi()' will return the value for that field in /etc/os-release. Here are some typical values found in os-release
#'
#' \itemize{
#'   \item PRETTY_NAME is a concatenation of NAME, VERSION_ID, VERSION
#'   \item NAME is the name of the OS, typically "Raspbian GNU/LINUX"
#'   \item VERSION_ID is the version. Currently = 11
#'   \item VERSION is a concatenation of VERSION_ID and (VERSION_CODENAME)
#'   \item VERSION_CODENAME is the OS Name. Currently = "bullseye"
#'   \item ID is the OS. Currently = "raspbian"
#'   \item ID_LIKE is the OS base. Currently = "debian"
#'   \item HOME_URL Currently = "http://www.raspbian.org"
#'   \item SUPPORT_URL Currently = "http://www.raspbian.org/RaspbianForums"
#'   \item BUG_REPORT Currently = "http://www.raspbian.org/RaspbianBugs"
#' }
#'
#' @return If `onlyThis` is specified, returns that value. Otherwise returns TRUE if running Raspbian
#' @export
#'
#' @examplesIf is.rpi()
#' is.rpi()
#' is.rpi("NAME")
is.rpi <- function(onlyThis = "IsThisRPI") {
  # First, test for presence of /etc/os-release
  theResult <- tryCatch(
    {
      utils::read.table("/etc/os-release", sep = "=")
    },
    warning = function(w) {
      FALSE
    },
    error = function(e) {
      FALSE
    },
    finally = {
      # cleanup
    }
  )

  if (onlyThis == "IsThisRPI") {
    if (isFALSE(theResult)) {
      # /etc/os-release wasn't found so this isn't Raspbian
      theReturnValue <- FALSE
    } else {
      # /etc/os-release was found, so this is at least debian
      osname <- theResult[theResult[1] == "ID", 2]
      if (osname == "raspbian") {
        # /etc/os-release is present and this is raspbian
        theReturnValue <- TRUE
      } else {
        # /etc/os-release is present, but this isn't raspbian
        # It might be a different version of debian
        theReturnValue <- FALSE
      }
    }
  } else {
    # someone wants to know specifics about this RPi
    theReturnValue <- theResult[theResult[1] == onlyThis, 2]
  }

  return(theReturnValue)
}