R/validation.R

In DivadNojnarg/outstanding-shiny-ui-code: Standalone Code for "Outstanding Shiny User Interfaces"

#' Validation function
#'
#' Validate a Tabler element width like \link{tabler_card}.
#'
#' @param width Value to validate.
#'
#' @return An error is raised if conditions are not met
#' @export
#'
#' @examples
#' \dontrun{
#'  validate_width(-1)
#'  validate_width(13)
#'  validate_width("string")
#' }
validate_width <- function(width) {
  if (is.numeric(width)) {
    if (width < 1 || width > 12) {
      stop("width must belong to [1, 12], as per Bootstrap 4 grid documentation. See more at https://getbootstrap.com/docs/4.0/layout/grid/")
    }
  } else {
    stop("width must be numeric")
  }
}



valid_statuses <- c(
  "primary",
  "secondary",
  "success",
  "info",
  "warning",
  "danger",
  "light",
  "dark"
)

#' Validation function
#'
#' Validate the status of a Tabler element like \link{tabler_card}.
#'
#' @param status Color to validate.
#'
#' @return TRUE if the test pass.
#' @export
#'
#' @examples
#' \dontrun{
#'  validate_status("danger")
#'  validate_status("maroon")
#' }
validate_status <- function(status) {

  if (is.null(status)) {
    return(TRUE)
  } else {
    if (status %in% valid_statuses) {
      return(TRUE)
    }
  }

  stop("Invalid status: ", status, ". Valid statuses are: ",
       paste(valid_statuses, collapse = ", "), ".")
}




valid_paddings <- c("sm", "md", "lg")

#' Validation function
#'
#' Validate a Tabler card padding. See \link{tabler_card}
#' for more informations.
#'
#' @param padding Padding value to validate.
#'
#' @return An error is raised if the input padding is not valid.
#' @export
#'
#' @examples
#' \dontrun{
#'  validate_padding("xs")
#'  validate_padding("sm")
#' }
validate_padding <- function(padding) {
  if (!is.null(padding)) {
    if (!(padding %in% valid_paddings)) {
      stop("Invalid status: ", padding, ". Valid choices are: ",
           paste(valid_paddings, collapse = ", "), ".")
    }
  }
}


# Return TRUE if a shiny.tag object has a CSS class, FALSE otherwise.
hasCssClass <- function(tag, class) {
  if (is.null(tag$attribs) || is.null(tag$attribs$class))
    return(FALSE)

  classes <- strsplit(tag$attribs$class, " +")[[1]]
  return(class %in% classes)
}


#' Check that a tag has specific properties
#'
#' Check for type and class. Raise an error if the conditions
#' are not fulfilled. This function is borrowed from shinydashboard.
#'
#' @param tag Tag to check.
#' @param type Expected type.
#' @param class Expected class.
#' @param allowUI ?
#'
#' @return An error if conditions are not met
#' @export
#'
#' @examples
#' \dontrun{
#'  library(shiny)
#'  myTag <- div(class = "bg-blue")
#'  tagAssert(myTag, type = "div")
#'  tagAssert(myTag, type = "li") # will fail
#'  tagAssert(myTag, class = "bg-blue")
#' }
tagAssert <- function(tag, type = NULL, class = NULL, allowUI = TRUE) {
  if (!inherits(tag, "shiny.tag")) {
    print(tag)
    stop("Expected an object with class 'shiny.tag'.")
  }

  # Skip dynamic output elements
  if (allowUI &&
      (hasCssClass(tag, "shiny-html-output") ||
       hasCssClass(tag, "shinydashboard-menu-output"))) {
    return()
  }

  if (!is.null(type) && tag$name != type) {
    stop("Expected tag to be of type ", type)
  }

  if (!is.null(class)) {
    if (is.null(tag$attribs$class)) {
      stop("Expected tag to have class '", class, "'")

    } else {
      tagClasses <- strsplit(tag$attribs$class, " ")[[1]]
      if (!(class %in% tagClasses)) {
        stop("Expected tag to have class '", class, "'")
      }
    }
  }
}




# This is like a==b, except that if a or b is NULL or an empty vector, it won't
# return logical(0). If a AND b are NULL/length-0, this will return TRUE; if
# just one of them is NULL/length-0, this will FALSE. This is for use in
# conditionals where `if(logical(0))` would cause an error. Similar to using
# identical(a,b), but less stringent about types: `equals(1, 1L)` is TRUE, but
# `identical(1, 1L)` is FALSE.
equals <- function(a, b) {
  alen <- length(a)
  blen <- length(b)
  if (alen==0 && blen==0) {
    return(TRUE)
  }
  if (alen > 1 || blen > 1) {
    stop("Can only compare objects of length 0 or 1")
  }
  if (alen==0 || blen==0) {
    return(FALSE)
  }

  a == b
}



#' Check that tag has specific properties
#'
#' Return TRUE if a tag object matches a specific id, and/or tag name, and/or
#  class, and or other arbitrary tag attributes. This function is borrowed from shinydashboard.
#'
#' @param item Tag to validate.
#' @param ... Any attribute to check (must be named).
#' @param id Expected id.
#' @param name Expected name.
#' @param class Expected class.
#'
#' @return TRUE or FALSE, depending on the test result.
#' @export
#'
#' @examples
#' \dontrun{
#'  library(shiny)
#'  myTag <- div(class = "bg-blue")
#'  tagMatches(myTag, id = "d")
#'  tagMatches(myTag, class = "bg-blue")
#' }
tagMatches <- function(item, ..., id = NULL, name = NULL, class = NULL) {
  dots <- list(...)
  if (!inherits(item, "shiny.tag")) {
    return(FALSE)
  }
  if (!is.null(id) && !equals(item$attribs$id, id)) {
    return(FALSE)
  }
  if (!is.null(name) && !equals(item$name, name)) {
    return(FALSE)
  }
  if (!is.null(class)) {
    if (is.null(item$attribs$class)) {
      return(FALSE)
    }
    classes <- strsplit(item$attribs$class, " ")[[1]]
    if (! class %in% classes) {
      return(FALSE)
    }
  }

  for (i in seq_along(dots)) {
    arg     <- dots[[i]]
    argName <- names(dots)[[i]]
    if (!equals(item$attribs[[argName]], arg)) {
      return(FALSE)
    }
  }

  TRUE
}




#' Validate a tab name
#'
#' Check if the provided tab name follows jQuery best practices
#'
#' @param tabName Tab name to validate
#'
#' @return An error if conditions are not met.
#' @export
#'
#' @examples
#' \dontrun{
#'  validate_tabName("plop")
#'  validate_tabName("plop*+?") # fails
#' }
#' @importFrom stringr str_extract_all str_c
validate_tabName <- function(tabName) {
  forbidden <- "(?!_)[[:punct:]]"
  wrong_selector <- grepl(forbidden, tabName, perl = TRUE)
  if (wrong_selector) {
    stop(
      paste(
        "Please do not use punctuation characters in tabNames.
        This might cause JavaScript issues."
      )
    )
  }
}




#' Find the child of the targeted element that has a specific attribute and value.
#'
#' This function takes a DOM element/tag object and reccurs within it until
#  it finds a child which has an attribute called `attr` and with value `val`
#  (and returns TRUE). If it finds an element with an attribute called `attr`
#  whose value is NOT `val`, it returns FALSE. If it exhausts all children
#  and it doesn't find an element with an attribute called `attr`, it also
#  returns FALSE. This function is borrowed from shinydashboard.
#'
#' @param x Parent tag.
#' @param attr Atttribute like id, class, data-toggle, ...
#' @param val Attribute value.
#'
#' @return TRUE or FALSE, depending on the search result
#' @export
findAttribute <- function(x, attr, val) {
  if (is.atomic(x)) return(FALSE) # exhausted this branch of the tree

  if (!is.null(x$attribs[[attr]])) { # found attribute called `attr`
    if (identical(x$attribs[[attr]], val)) return(TRUE)
    else return(FALSE)
  }

  if (length(x$children) > 0) { # recursion
    return(any(unlist(lapply(x$children, findAttribute, attr, val))))
  }

  return(FALSE) # found no attribute called `attr`
}




#' Validate a \link{tabler_progress} value
#'
#' @param value Value to validate.
#'
#' @return An error is raised if the value does not met expectations.
#' @export
validate_progress_value <- function(value) {
  if (!is.numeric(value)) stop("Progress value must be numeric!")
  range <- (value >= 0 && value <= 100)
  if (!(range)) stop("Progress value must be between 0 and 100.")
}