module Mdown2PDF

asset(name) click to toggle source

Returns an absolute path for a given asset.

# File lib/mdown2pdf.rb, line 109
def asset(name)
  File.expand_path(File.join(__dir__, '..', 'assets', name))
end

html_for(markdown) click to toggle source

Converts a given Markdown string to HTML.

# File lib/mdown2pdf.rb, line 96
def html_for(markdown)
  parser = Redcarpet::Markdown.new(Render, {
    fenced_code_blocks: true,
    tables:             true,
    superscript:        true,
    strikethrough:      true,
    autolink:           true
  })

  parser.render(markdown)
end

markdown_for(file) click to toggle source

Converts a given Markdown file to an HTML document. The underlying implementation uses Redcarpet but you should check out the Render class for further information.

# File lib/mdown2pdf.rb, line 91
def markdown_for(file)
  html_for(File.read(file))
end

output(file: , name: , cover: nil, toc: false) click to toggle source

Actually outputs a given HTML file as a PDF for a given name through the `wkhtmltopdf` command line tool.

- The given `:file` key represents the HTML file to translate
  to PDF.
- `:name` will be used to infer the PDF file's name.
- `:cover` can be used if a document should be used as a cover.
- `:toc` specifies whether a table of contents should be generated
   or not for the document.

# File lib/mdown2pdf.rb, line 66
def output(file: , name: , cover: nil, toc: false)
  stylesheet = ["--user-style-sheet", asset('style.css')]
  arguments  = ["wkhtmltopdf"]

  if cover
    arguments.push("cover", cover)
    arguments.push(*stylesheet)
  end

  arguments.push("toc", "--xsl-style-sheet", asset("toc.xsl")) if toc

  arguments.push(
    file,
    "--include-in-outline",
    "--enable-internal-links",
    *stylesheet,
    name.sub(/.(md|mdwon)/, '.pdf')
  )

  `#{arguments.join(" ")}`
end

temporary_html_files_for(file) { |output_file, cover_file| ... } click to toggle source

Creates two temporary files:

* One to represent the eventual cover of the PDF file.
* One with the document translated to HTML.

These two temporary files will be used by Wkhtmltopdf to generate the final PDF file.

This method requires a block that will yield a path for each file. For example:

temporary_files_for("a_file.md") do |output, cover|
  # Here `output` and `cover` are paths.
end

To distinguish the cover from the rest of the document, the user must put an h-rule inside their document and the first one will be used as a separator.

# File lib/mdown2pdf.rb, line 26
def temporary_html_files_for(file)
  seed        = (rand * 100).round
  output_file = "/tmp/output-#{seed}.html"
  cover_file  = "/tmp/cover-#{seed}.html"

  document = markdown_for(file)
  first_hr = document.index('<hr>')

  if first_hr
    cover    = document[0...first_hr]
    document = document[first_hr+4..-1]
  end

  File.open(output_file, "w") do |f|
    f.write(File.read(asset('output.html')) % { content: document })
  end

  if cover
    File.open(cover_file, "w") do |f|
      f.write(File.read(asset('output.html')) % { content: cover })
    end

    yield(output_file, cover_file)
  else
    yield(output_file, nil)
  end
ensure
  File.delete(output_file)
  File.delete(cover_file) if File.exist?(cover_file)
end

Constants

Public Instance Methods