R/utils.R

In JohnCoene/ambiorix: Web Framework Inspired by 'Express.js'

#' Browse App
#'
#' Browses the application, if RStudio available uses pane.
#'
#' @param open Whether to open the app.
#' @param url URL to browse.
#'
#' @noRd
#' @keywords internal
browse_ambiorix <- function(open, url){
  if(!open) return()

  viewer <- getOption("viewer", browseURL)

  x <- tryCatch(
    viewer(url),
    error = function(e) e
  )

  if(inherits(x, "error"))
    cat("Unable to open browser, please open manually.\n")

  invisible()
}

`%response%` <- function(lhs, rhs){
  if(is.null(lhs)) return(rhs)
  if(!inherits(lhs, "ambiorixResponse")) return(rhs)
  return(lhs)
}

`%error%` <- function(lhs, rhs){
  if(is.null(lhs)) return(rhs)
  return(lhs)
}

#' Remove Extensions
#'
#' Remove extensions from files.
#'
#' @noRd
#' @keywords internal
remove_extensions <- function(files){
  tools::file_path_sans_ext(files)
}

#' Checks if Package is Installed
#'
#' Checks if a package is installed, stops if not.
#'
#' @param pkg Package to check.
#'
#' @noRd
#' @keywords internal
check_installed <- function(pkg){
  has_it <- base::requireNamespace(pkg, quietly = TRUE)

  if(!has_it)
    stop(sprintf("This function requires the package {%s}", pkg), call. = FALSE)
}

#' Retrieve the Port for Server Binding
#'
#' Determines the appropriate port for the server, following a
#' specific order of precedence.
#'
#' @param host String. The host address to bind to when selecting a random port.
#' @param port Integer. An optional input port, provided by the user.
#' @details The port to use is resolved in the following order of precedence:
#' 1. Forced Port Option: Typically used by Belgic, the load balancer. If
#'   the `ambiorix.port.force` R option is specified, this port is returned.
#'   This option should not be altered during development.
#' 2. `AMBIORIX_PORT` environment variable
#' 3. `port` argument.
#' 4. `SHINY_PORT` environment variable.
#' 5. Random port.
#'
#' @return Integer. Port value to bind the server.
#'
#' @noRd
#' @keywords internal
get_port <- function(host, port = NULL){
  # we need to override the port if the load balancer
  # is running. This should NOT be set by a dev
  # this ensures we can overwrite
  forced <- getOption("ambiorix.port.force")
  if(!is.null(forced))
    return(forced)

  has_ints_only <- function(x) !grepl(pattern = "\\D", x = x)
  is_valid_port <- function(x) !is.null(x) && !identical(x, "") && has_ints_only(x)

  ambiorix_port <- Sys.getenv("AMBIORIX_PORT")
  if (is_valid_port(ambiorix_port))
    return(as.integer(ambiorix_port))

  if (is_valid_port(port))
    return(as.integer(port))

  shiny_port <- Sys.getenv("SHINY_PORT")
  if (is_valid_port(shiny_port))
    return(as.integer(shiny_port))

  httpuv::randomPort(host = host)
}

#' Make label
#' 
#' Cheap replacement for rlang::as_label to avoid dependency.
#' Must fix.
#' 
#' @noRd
#' @keywords internal
as_label <- function(x) {
  name <- tryCatch(
    is.character(x),
    error = function(e) e
  )

  if(!inherits(name, "error"))
    return(x)

  deparse(substitute(x, parent.frame()))
}

#' Silent readLines
#' 
#' Avoids EOF warnings.
#' 
#' @param ... Passed to [readLines()]:
#' 
#' @keywords internal
read_lines <- function(...) {
  suppressWarnings(
    readLines(...)
  )
}

#' Read file from disk or cache
#' 
#' @param path Path to file.
#' 
#' @keywords internal
read_lines_cached <- function(path) {
  if(!.globals$cache_tmpls)
    return(read_lines(path))

  if(length(.cache_tmpls[[path]]) > 0L)
    return(.cache_tmpls[[path]])

  content <- read_lines(path)
  .cache_tmpls[[path]] <- content
  return(content)
}