问闪亮降级火锅5至4

EN

##install new shiny version
install.packages("shiny") #install newest shiny
library(shiny)
library(htmltools) 


#source in this function to globalEnv

#' Legacy means good old iconic times
#'
#' @param local_path_fa_4.7.1 
#' @param shiny_path
#'
#' @return
#' @export
#' @import shiny htmltools
#' @details #this installs legacy font-awesome and return a function  similar to icon
#'
#' @examples 
#' 
#' install.packages("shiny") #install newest shiny
#' library(shiny)
#' library(htmltools)
#' my_fa_path = "./misc/global_source/fa_shiny_4.7.1/font-awesome"
#' icon_legacy = activate_icon_legacy(my_fa_path) #tadaaa use icon_legacy now
#' #btw css pseudo-elements seem to work out-of-the-box also
#' 
#' icon = icon_legacy #you may also feel like placing icon in global env to override shiny::icon
activate_icon_legacy = function(
  local_path_fa_4.7.1,
  shiny_path = system.file(package="shiny")
) {

  #find out what version of shiny is installed
  uses_fontawesome5 = packageVersion("shiny")>=1.2 #because implemented since 1.2
  shiny_resource_path = paste0(shiny_path,"/www/shared")
  misses_fontawesome4  = !"font-awesome" %in% list.files(shiny_resource_path) #because new fa dir is called 'fontawesome'


  #if legacy dir is missing from library copy into installed library
  if(uses_fontawesome5 && misses_fontawesome4) { 
    file.copy(
      from = local_path_fa_4.7.1,
      to = shiny_resource_path,
      recursive = TRUE,copy.mode = FALSE
    )
  }

  #import minor dependency from shiny library into closure
  font_awesome_brands = shiny:::font_awesome_brands
  tags = htmltools::tags


  #source this modified icon() function from library/shiny/R/bootstrap.R
  #notice the legacy feature if true will use old fa 4.7.1 else new
  icon_legacy <- function(name, class = NULL, lib = "font-awesome",legacy=TRUE) {
    prefixes <- list(
      "font-awesome" = "fa",
      "glyphicon" = "glyphicon"
    )
    prefix <- prefixes[[lib]]

    # determine stylesheet
    if (is.null(prefix)) {
      stop("Unknown font library '", lib, "' specified. Must be one of ",
           paste0('"', names(prefixes), '"', collapse = ", "))
    }

    # build the icon class (allow name to be null so that other functions
    # e.g. buildTabset can pass an explicit class value)
    iconClass <- ""
    if (!is.null(name)) {
      prefix_class <- prefix
      if (prefix_class == "fa" && name %in% font_awesome_brands) {
        prefix_class <- "fab"
      }
      iconClass <- paste0(prefix_class, " ", prefix, "-", name)
    }
    if (!is.null(class))
      iconClass <- paste(iconClass, class)

    iconTag <- tags$i(class = iconClass)

    # font-awesome needs an additional dependency (glyphicon is in bootstrap)
    if (lib == "font-awesome") {
      if(legacy) {
        htmlDependencies(iconTag) <- htmlDependency(
          "fontwesome","4.7.1", "www/shared/font-awesome", package = "shiny",
          stylesheet = c("css/font-awesome.css","font-awesome.min.css"))
      } else {
        htmlDependencies(iconTag) <- htmlDependency(
          "font-awesome", "5.3.1", "www/shared/fontawesome", package = "shiny",
          stylesheet = c("css/all.min.css","css/v4-shims.min.css")
        )
      }

    }

    htmltools::browsable(iconTag)
  }

  return(icon_legacy)
}


#download extract fontawesome 4.7.1 and write path here
my_fa_path = "./misc/global_source/fa_shiny_4.7.1/font-awesome"
icon_legacy = activate_icon_legacy(my_fa_path) #tadaaa use icon_legacy now
#btwcss pseudos seem to work out-of-the-box also

#one may also feel like placing icon_legacy() as icon() in globalEnv to override shiny::icon
#if youre too lazy change all your original code. This will work any code in ui.R and server.R
#however packages with explicit namespaces are likely not overridden by this.
icon = icon_legacy

#now shiny code will behave like this
icon("table",legacy=TRUE)  # old style 9 cell table
icon("table",legacy=FALSE) # new fat 4 cell table


#...one may feel like opting for more explicit and strict namespace solution wrapped in some package.
#but that would be a lot more boiler plate code not relevant for this answer

#this solution also fixed my fontawesome CSS pseudo-elements issues