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pandoc_available <- function(version = NULL) {
# ensure we've scanned for pandoc
find_pandoc()
# check availability
if (!is.null(.pandoc$dir))
if (!is.null(version))
.pandoc$version >= version
else
TRUE
else
FALSE
}
pandoc_save_markdown <- function(html, file, background = "white", title, libdir = "lib") {
# Forked from htmltools::save_html to work better with pandoc_self_contained_html
# ensure that the paths to dependencies are relative to the base
# directory where the webpage is being built.
if (is.character(file)) {
dir <- normalizePath(dirname(file), mustWork = TRUE)
file <- file.path(dir, basename(file))
owd <- setwd(dir)
on.exit(setwd(owd), add = TRUE)
}
rendered <- renderTags(html)
deps <- lapply(rendered$dependencies, function(dep) {
dep <- htmltools::copyDependencyToDir(dep, libdir, FALSE)
dep <- htmltools::makeDependencyRelative(dep, dir, FALSE)
dep
})
# Build the markdown page. Anything that goes into the eventual <head> goes in
# the yaml header, and will be rendered using the pandoc template.
html <- c(
"---",
yaml::as.yaml(list(
title = htmltools::htmlEscape(title),
"header-include" = renderDependencies(deps, c("href", "file")),
"head" = rendered$head,
"background-color" = htmltools::htmlEscape(background, attribute = TRUE)
)),
"---",
rendered$html
)
# write it
writeLines(html, file, useBytes = TRUE)
}
# The input should be the path to a file that was created using pandoc_save_markdown
pandoc_self_contained_html <- function(input, output) {
# make input file path absolute
input <- normalizePath(input)
# ensure output file exists and make it's path absolute
if (!file.exists(output))
file.create(output)
output <- normalizePath(output)
# create a template
template <- tempfile(fileext = ".html")
writeLines(c(
"<!DOCTYPE html>",
"<html>",
"<head>",
"<meta charset=\"utf-8\"/>",
"<title>$title$</title>",
"$for(header-include)$",
"$header-include$",
"$endfor$",
"$for(head)$",
"$head$",
"$endfor$",
"</head>",
"<body style=\"background-color: $background-color$;\">",
"$body$",
"</body>",
"</html>"
), template)
# convert from markdown to html to get base64 encoding
# (note there is no markdown in the source document but
# we still need to do this "conversion" to get the
# base64 encoding)
pandoc_convert(
input = input,
from = "markdown",
output = output,
options = c(
"--self-contained",
"--template", template
)
)
invisible(output)
}
pandoc_convert <- function(input,
to = NULL,
from = NULL,
output = NULL,
citeproc = FALSE,
options = NULL,
verbose = FALSE,
wd = NULL) {
# ensure we've scanned for pandoc
find_pandoc()
# execute in specified working directory
if (is.null(wd)) {
wd <- base_dir(input)
}
oldwd <- setwd(wd)
on.exit(setwd(oldwd), add = TRUE)
# input file and formats
args <- c(input)
if (!is.null(to))
args <- c(args, "--to", to)
if (!is.null(from))
args <- c(args, "--from", from)
# output file
if (!is.null(output))
args <- c(args, "--output", output)
# additional command line options
args <- c(args, options)
# set pandoc stack size
stack_size <- getOption("pandoc.stack.size", default = "512m")
args <- c(c("+RTS", paste0("-K", stack_size), "-RTS"), args)
# build the conversion command
command <- paste(quoted(pandoc()), paste(quoted(args), collapse = " "))
# show it in verbose mode
if (verbose)
cat(command, "\n")
# run the conversion
with_pandoc_safe_environment({
result <- system(command)
})
if (result != 0)
stop("pandoc document conversion failed with error ", result, call. = FALSE)
invisible(NULL)
}
# get the path to the pandoc binary
pandoc <- function() {
find_pandoc()
file.path(.pandoc$dir, "pandoc")
}
# Scan for a copy of pandoc and set the internal cache if it's found.
find_pandoc <- function() {
if (is.null(.pandoc$dir)) {
# define potential sources
sys_pandoc <- Sys.which("pandoc")
sources <- c(Sys.getenv("RSTUDIO_PANDOC"),
ifelse(nzchar(sys_pandoc), dirname(sys_pandoc), ""))
if (!is_windows())
sources <- c(sources, path.expand("~/opt/pandoc"))
# determine the versions of the sources
versions <- lapply(sources, function(src) {
if (file.exists(src))
get_pandoc_version(src)
else
numeric_version("0")
})
# find the maximum version
found_src <- NULL
found_ver <- numeric_version("0")
for (i in 1:length(sources)) {
ver <- versions[[i]]
if (ver > found_ver) {
found_ver <- ver
found_src <- sources[[i]]
}
}
# did we find a version?
if (!is.null(found_src)) {
.pandoc$dir <- found_src
.pandoc$version <- found_ver
}
}
}
# wrap a system call to pandoc so that LC_ALL is not set
# see: https://github.com/rstudio/rmarkdown/issues/31
# see: https://ghc.haskell.org/trac/ghc/ticket/7344
with_pandoc_safe_environment <- function(code) {
lc_all <- Sys.getenv("LC_ALL", unset = NA)
if (!is.na(lc_all)) {
Sys.unsetenv("LC_ALL")
on.exit(Sys.setenv(LC_ALL = lc_all), add = TRUE)
}
lc_ctype <- Sys.getenv("LC_CTYPE", unset = NA)
if (!is.na(lc_ctype)) {
Sys.unsetenv("LC_CTYPE")
on.exit(Sys.setenv(LC_CTYPE = lc_ctype), add = TRUE)
}
if (Sys.info()['sysname'] == "Linux" &&
is.na(Sys.getenv("HOME", unset = NA))) {
stop("The 'HOME' environment variable must be set before running Pandoc.")
}
if (Sys.info()['sysname'] == "Linux" &&
is.na(Sys.getenv("LANG", unset = NA))) {
# fill in a the LANG environment variable if it doesn't exist
Sys.setenv(LANG=detect_generic_lang())
on.exit(Sys.unsetenv("LANG"), add = TRUE)
}
if (Sys.info()['sysname'] == "Linux" &&
identical(Sys.getenv("LANG"), "en_US")) {
Sys.setenv(LANG="en_US.UTF-8")
on.exit(Sys.setenv(LANG="en_US"), add = TRUE)
}
force(code)
}
# if there is no LANG environment variable set pandoc is going to hang so
# we need to specify a "generic" lang setting. With glibc >= 2.13 you can
# specify C.UTF-8 so we prefer that. If we can't find that then we fall back
# to en_US.UTF-8.
detect_generic_lang <- function() {
locale_util <- Sys.which("locale")
if (nzchar(locale_util)) {
locales <- system(paste(locale_util, "-a"), intern = TRUE)
locales <- suppressWarnings(
strsplit(locales, split = "\n", fixed = TRUE)
)
if ("C.UTF-8" %in% locales)
return ("C.UTF-8")
}
# default to en_US.UTF-8
"en_US.UTF-8"
}
# quote args if they need it
quoted <- function(args) {
spaces <- grepl(' ', args, fixed=TRUE)
args[spaces] <- shQuote(args[spaces])
args
}
# Find common base directory, throw error if it doesn't exist
base_dir <- function(x) {
abs <- vapply(x, tools::file_path_as_absolute, character(1))
base <- unique(dirname(abs))
if (length(base) > 1) {
stop("Input files not all in same directory, please supply explicit wd",
call. = FALSE)
}
base
}
# Get an S3 numeric_version for the pandoc utility at the specified path
get_pandoc_version <- function(pandoc_dir) {
pandoc_path <- file.path(pandoc_dir, "pandoc")
with_pandoc_safe_environment({
version_info <- system(paste(shQuote(pandoc_path), "--version"),
intern = TRUE)
})
version <- strsplit(version_info, "\n")[[1]][1]
version <- strsplit(version, " ")[[1]][2]
numeric_version(version)
}
is_windows <- function() {
identical(.Platform$OS.type, "windows")
}
# Environment used to cache the current pandoc directory and version
.pandoc <- new.env()
.pandoc$dir <- NULL
.pandoc$version <- NULL
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