Concat filter for nanoc

nanoc-filter-concat.rb

module Nanoc::Filters

  require 'pathname'

  class Concat < Nanoc::Filter

    identifier :concat

    def item_pathname(item)
      Pathname.new(File.join("content", item[:content_filename]))
    end

    # Concatenates files specified by the item's `sources` metadata. These
    # files are loaded relative to the item's directory.
    #
    # @param [String] content The content to filter
    #
    # @return [String] The concatenated files or (if unspecified) the origina
    #                  file content.
    def run(content, params = {})
      sources = assigns[:item].attributes[:sources]

      if sources.kind_of?(Array)
        if content != ""
          throw "Concat filter: Items may not define both unique content and a `sources` list."
        end

        dependencies = []
        #directory = Pathname.new(File.join("content", assigns[:item].path)).dirname.realpath
        directory = self.item_pathname(assigns[:item]).dirname.realpath

        content = sources.map do |file_name|
          file_name = Pathname.new(file_name)
          if file_name.relative?
            file_name = directory + file_name
          end

          if !file_name.exist?
            throw "Concat filter - Cannot locate file #{file_name}."
          end

          file_name = file_name.realpath

          # Build list of nanoc items that the current item depends on
          found = false
          @items.each do |item|
            if self.item_pathname(item).realpath == file_name
                dependencies << item
                found = true
                break
            end
          end

          if !found
            throw "Concat filter - The file #{file_name} has no associated nanoc item."
          end

          File.read(file_name)
        end.join("\n")

        if dependencies.length > 0
          depend_on dependencies
        end
      end

      content
    end

  end
end