Script to migrate blog from Middleman to Gatsby

migrate.rb

#!/usr/bin/ruby

require 'rake'
require 'yaml'
require 'date'

OLD_ROOT_DIR = "/Users/ashfurrow/bin/blog/source"
OLD_MD_DIR = "/Users/ashfurrow/bin/blog/source/blog"
NEW_MD_DIR = "/Users/ashfurrow/bin/blog2/blog"

YAML_FRONT_MATTER_REGEXP = /\A(---\s*\n.*?\n?)^((---|\.\.\.)\s*$\n?)/m
IMAGE_REGEXP = %r{(\/img\/[^"\)]*)["\)]}

puts "Starting...\n#{Array.new(80).map { '-' }.join('')}\n\n\n"
old_posts = FileList.new("#{OLD_MD_DIR}/*").to_a
puts "Migrating #{old_posts.length} posts."

results = old_posts.map do |filename|
  puts "  Migrating #{filename}"
  file = File.read(filename)
  raise "Bad file: #{filename}" unless file =~ YAML_FRONT_MATTER_REGEXP
  data, content = YAML.load($1), Regexp.last_match.post_match

  stripped_filename = filename.split("/").last.match(%r{(\d\d\d\d-\d\d-\d\d)-.*.html.(markdown|slim)})[1]
  new_post_dir = "#{NEW_MD_DIR}/#{stripped_filename}"
  puts "    Making new directory #{new_post_dir}"
  output = `mkdir #{new_post_dir} 2>&1`
  
  date = DateTime.parse(data["date"])
  map = {
    "title" => data["title"],
    "createdDate" => date.strftime("%F"),
    "updatedDate" => date.strftime("%F"),
    "author" => "Ash Furrow"
  }
  background_image = data["background_image"]
  if !background_image.nil?
    map["image"] = background_image.split("/").last
    old_filename = "#{OLD_ROOT_DIR}#{background_image}"
    raise "File does not exist: #{old_filename}" unless File.exists?(old_filename)    
    `cp #{old_filename} #{new_post_dir}/#{map['image']}`
  end
  og_image = data["og_image"]
  if !og_image.nil?
    map["socialImage"] = og_image.split("/").last
    old_filename = "#{OLD_ROOT_DIR}#{og_image}"
    raise "File does not exist: #{old_filename}" unless File.exists?(old_filename)    
    `cp #{old_filename} #{new_post_dir}/#{map['socialImage']}`    
  end

  # Look for any local images and move
  content.scan(IMAGE_REGEXP).select { |m| m[0].start_with? "/" }.map(&:first).each do |match|
    old_filename = "#{OLD_ROOT_DIR}#{match}"
    raise "File does not exist: #{old_filename}" unless File.exists?(old_filename)
    content.gsub!(match, match.split("/").last)
    `cp #{old_filename} #{new_post_dir}/#{match.split("/").last}`        
  end

  raise "Help! Reference old image dir! #{filename}, #{content}" if content.include? "/img/"

  # TODO: Replace YOUTUBE

  # map
  # stripped_filename
  new_file = <<~EOS
  #{YAML.dump(map)}---
  #{content}
  EOS
  File.open("#{new_post_dir}/index.md", "w") { |f| f.write(new_file) }
  true
end

puts results.to_a.uniq