middleman/middleman-core/lib/middleman-core/extensions/asset_hash.rb

require 'addressable/uri'
require 'middleman-core/util'
require 'middleman-core/rack'

class Middleman::Extensions::AssetHash < ::Middleman::Extension
  option :exts, %w(.jpg .jpeg .png .gif .webp .js .css .otf .woff .woff2 .eot .ttf .svg), 'List of extensions that get asset hashes appended to them.'
  option :ignore, [], 'Regexes of filenames to skip adding asset hashes to'

  def initialize(app, options_hash={}, &block)
    super

    require 'digest/sha1'
    require 'rack/mock'
    require 'middleman-core/middleware/inline_url_rewriter'
  end

  def after_configuration
    # Allow specifying regexes to ignore, plus always ignore apple touch icons
    @ignore = Array(options.ignore) + [/^apple-touch-icon/]

    app.use ::Middleman::Middleware::InlineURLRewriter,
            id: :asset_hash,
            url_extensions: options.exts,
            source_extensions: %w(.htm .html .php .css .js),
            ignore: @ignore,
            middleman_app: app,
            proc: method(:rewrite_url)
  end

  Contract String, Or[String, Pathname], Any => Maybe[String]
  def rewrite_url(asset_path, dirpath, _request_path)
    uri = ::Addressable::URI.parse(asset_path)
    relative_path = uri.path[0..0] != '/'

    full_asset_path = if relative_path
      dirpath.join(asset_path).to_s
    else
      asset_path
    end

    return unless asset_page = app.sitemap.find_resource_by_destination_path(full_asset_path) || app.sitemap.find_resource_by_path(full_asset_path)

    replacement_path = "/#{asset_page.destination_path}"
    replacement_path = Pathname.new(replacement_path).relative_path_from(dirpath).to_s if relative_path

    replacement_path
  end

  # Update the main sitemap resource list
  # @return Array<Middleman::Sitemap::Resource>
  Contract ResourceList => ResourceList
  def manipulate_resource_list(resources)
    @rack_client ||= begin
      rack_app = ::Middleman::Rack.new(app).to_app
      ::Rack::MockRequest.new(rack_app)
    end

    # Process resources in order: binary images and fonts, then SVG, then JS/CSS.
    # This is so by the time we get around to the text files (which may reference
    # images and fonts) the static assets' hashes are already calculated.
    resources.sort_by do |a|
      if %w(.svg .svgz).include? a.ext
        0
      elsif %w(.js .css).include? a.ext
        1
      else
        -1
      end
    end.each(&method(:manipulate_single_resource))
  end

  Contract IsA['Middleman::Sitemap::Resource'] => Maybe[IsA['Middleman::Sitemap::Resource']]
  def manipulate_single_resource(resource)
    return unless options.exts.include?(resource.ext)
    return if ignored_resource?(resource)
    return if resource.ignored?

    # Render through the Rack interface so middleware and mounted apps get a shot
    response = @rack_client.get(
      URI.escape(resource.destination_path),
      'bypass_inline_url_rewriter_asset_hash' => 'true'
    )

    raise "#{resource.path} should be in the sitemap!" unless response.status == 200

    digest = Digest::SHA1.hexdigest(response.body)[0..7]

    resource.destination_path = resource.destination_path.sub(/\.(\w+)$/) { |ext| "-#{digest}#{ext}" }
    resource
  end

  Contract IsA['Middleman::Sitemap::Resource'] => Bool
  def ignored_resource?(resource)
    @ignore.any? do |ignore|
      Middleman::Util.path_match(ignore, resource.destination_path)
    end
  end
end