R/get_yml_inputs.R

In TuCai/phuse: Web Application Framework for 'PhUSE' Scripts

#' Get Inputs from Script Metadata File
#' @description Get inputs from script metadata.
#' @param fn a file name or URL pointing to script metadata file
#' @return a list of input values provided for the script
#' @export
#' @importFrom RCurl url.exists
#' @examples
#'   a <- "https://github.com/phuse-org/phuse-scripts/raw/master"
#'   b <- "development/R/scripts"
#'   c <- "Draw_Dist2_R.yml"
#'   f1 <- paste(a,b,c, sep = '/')
#'   r1 <- get_inputs(f1)
#' @author Hanming Tu
#' @name get_yml_inputs
# ---------------------------------------------------------------------------
# HISTORY   MM/DD/YYYY (developer) - explanation
#  09/17/2017 (htu) - initial creation
#
get_yml_inputs <- function(fn = NULL) {
  r <- list()
  # 1. get the script name
  sfo <- sys.frame(1)$ofile
  if (is.null(fn) && is.null(sfo)) {
    cat("ERROR: no script metadata file name is provided.\n");
    return(r)
  }
  yml_name <- ifelse(is.null(fn), sfo, fn)
  # 2. check file existence
  if (!(file.exists(yml_name) || url.exists(yml_name))) {
    cat(paste0("ERROR: ", yml_name, " does not exist"))
    return(r)
  }
  # 3. read YML content
  cfg <- read_yml(yml_name)
  if (! ("Inputs" %in% names(cfg) || "Parameters" %in% names(cfg) )) {
    cat(paste0("ERROR: no Inputs defined in ", yml_name))
    return(r)
  }
  if ("Inputs" %in% names(cfg)) {
    r <- cfg$Inputs;
  }
  if ("Parameters" %in% names(cfg)) {
    r[length(r)+1] <- cfg$Parameters;
  }

  # k <- 0
  # for (i in 1:20) {
  #  v <- paste0("p", i)
  #  if (v %in% names(cfg$Inputs)) { k <- k + 1;
  #  # we need to remove any R Shiny specification here
  #  r[k] <- gsub('\\s+-.+','', cfg$Inputs[[v]])
  #  }
  #}
  return(r)
}