R/cdnify_leaflet.R

In szego/cdnce: Use CDNs for Web Dependencies

#' CDNify a **tufte** page
#'
#' This function replaces dependencies in [leaflet](https://rstudio.github.io/leaflet/)
#' .html pages generated using [htmlwidgets::saveWidget()].
#'
#' The page must have been saved with `selfcontained = FALSE` in the
#' call to [htmlwidgets::saveWidget()].
#'
#' @param filename .html file to CDNify.
#' @param libdir Directory containing dependencies (defaults to filename_files).
#'
#' @export
cdnify_leaflet <- function(filename, libdir = sub(".html$", "_files", filename)) {
  if(missing(filename))
    stop("Argument 'filename' must be provided.")

  filename %>%
    readLines() %>%
    stringr::str_replace(
      "=\"[^\"]*htmlwidgets-([0-9\\.]+)/htmlwidgets.js\"",
      "=\"https://cdn.jsdelivr.net/gh/ramnathv/htmlwidgets@\\1/inst/www/htmlwidgets.js\""
    ) %>%
    stringr::str_replace(
      "=\"[^\"]*jquery-([0-9\\.]+)/jquery.min.js\"",
      "=\"https://code.jquery.com/jquery-\\1.min.js\""
    ) %>%
    stringr::str_replace_all(  # replaces leaflet.js and leaflet.css
      "=\"[^\"]*leaflet-([0-9\\.]+)/leaflet",
      "=\"https://unpkg.com/leaflet@\\1/dist/leaflet"
    ) %>%
    stringr::str_replace(
      "=\"[^\"]*Proj4Leaflet-([0-9\\.]+)/proj4leaflet.js\"",
      "=\"https://unpkg.com/proj4leaflet@\\1/src/proj4leaflet.js\""
    ) %>%
    stringr::str_replace(
      "=\"[^\"]*proj4-([0-9\\.]+)/proj4.min.js\"",
      "=\"https://unpkg.com/proj4@\\1/dist/proj4.js\""
    ) %>%
    stringr::str_replace(
      "=\"[^\"]*leaflet-binding-([0-9\\.]+)/leaflet.js\"",
      "=\"https://cdn.jsdelivr.net/gh/rstudio/leaflet/inst/htmlwidgets/leaflet.js\""
    ) %>%
    stringr::str_replace(
      "=\"[^\"]*leafletfix-([0-9\\.]+)/leafletfix.css\"",
      "=\"https://cdn.jsdelivr.net/gh/rstudio/leaflet/inst/htmlwidgets/lib/leafletfix/leafletfix.css\""
    ) %>%
    stringr::str_replace(
      "=\"[^\"]*rstudio_leaflet-([0-9\\.]+)/rstudio_leaflet.css\"",
      "=\"https://cdn.jsdelivr.net/gh/rstudio/leaflet/inst/htmlwidgets/lib/rstudio_leaflet/rstudio_leaflet.css\""
    ) %>%
    writeLines(filename)

  to_delete <-
    c(
      "/htmlwidgets-([0-9\\.]+)$",
      "/jquery-([0-9\\.]+)$",
      "/leaflet-([0-9\\.]+)$",
      "/Proj4Leaflet-([0-9\\.]+)$",
      "/proj4-([0-9\\.]+)$",
      "/leaflet-binding-([0-9\\.]+)$",
      "/leafletfix-([0-9\\.]+)$",
      "/rstudio_leaflet-([0-9\\.]+)$"
    ) %>%
    paste(collapse = "|") %>%
    paste0("(", ., ")")

  libdir %>%
    list.dirs(full.names = TRUE, recursive = TRUE) %>%
    .[which(stringr::str_detect(., to_delete))] %>%
    unlink(recursive = TRUE)

  invisible()
}