rails initializer for sprockets patch

config_initializers_sprockets_patch.rb

# Avoid a funky bug in Sprockets
#   https://github.com/rails/sprockets/issues/749
# made serving files likes /assets/logos/layout-logo-compact.svg
# impossible under certain circumstances.

class MonkeyPatch🐒ObsoleteCheck < StandardError
end

CURRENT_SPROCKETS_VERSION_WITHOUT_PATCH = "4.2.1"

if Sprockets::VERSION != CURRENT_SPROCKETS_VERSION_WITHOUT_PATCH
  raise MonkeyPatch🐒ObsoleteCheck.new(
    <<-MESSAGE
      Sprockets was updated! (finally?)
      Has https://github.com/rails/sprockets/pull/793/ been merged?'
      -> If so, delete this file.

      Offending spec is e.g.:
        `rspec ./spec/dependsonyourprojcet.rb:5`
    MESSAGE
  )
end

# Patch from https://github.com/rails/sprockets/pull/793/
module Sprockets
  # `Server` is a concern mixed into `Environment` and
  # `CachedEnvironment` that provides a Rack compatible `call`
  # interface and url generation helpers.
  module Server
    def call(env)
      start_time = Time.now.to_f
      time_elapsed = lambda { ((Time.now.to_f - start_time) * 1000).to_i }

      unless ALLOWED_REQUEST_METHODS.include? env['REQUEST_METHOD']
        return method_not_allowed_response
      end

      msg = "Served asset #{env['PATH_INFO']} -"

      # Extract the path from everything after the leading slash
      full_path = Rack::Utils.unescape(env['PATH_INFO'].to_s.sub(/^\//, ''))
      path = full_path

      return bad_request_response(env) unless path.valid_encoding?
      return forbidden_response(env) if forbidden_request?(path)

      asset = find_asset(path)

      # Strip fingerprint
      if asset.nil? && fingerprint = path_fingerprint(path)
        path = path.sub("-#{fingerprint}", '')
        return forbidden_response(env) if forbidden_request?(path)
        asset = find_asset(path)
      end

      if fingerprint
        if_match = asset&.etag
      elsif env['HTTP_IF_MATCH']
        if_match = env['HTTP_IF_MATCH'][/"(\w+)"$/, 1]
      end

      if env['HTTP_IF_NONE_MATCH']
        if_none_match = env['HTTP_IF_NONE_MATCH'][/"(\w+)"$/, 1]
      end

      if asset.nil?
        status = :not_found
      elsif fingerprint && asset.etag != fingerprint
        status = :not_found
      elsif if_match && asset.etag != if_match
        status = :precondition_failed
      elsif if_none_match && asset.etag == if_none_match
        status = :not_modified
      else
        status = :ok
      end

      case status
      when :ok
        logger.info "#{msg} 200 OK (#{time_elapsed.call}ms)"
        ok_response(asset, env)
      when :not_modified
        logger.info "#{msg} 304 Not Modified (#{time_elapsed.call}ms)"
        not_modified_response(env, if_none_match)
      when :not_found
        logger.info "#{msg} 404 Not Found (#{time_elapsed.call}ms)"
        not_found_response(env)
      when :precondition_failed
        logger.info "#{msg} 412 Precondition Failed (#{time_elapsed.call}ms)"
        precondition_failed_response(env)
      end
    rescue Exception => e
      logger.error "Error compiling asset #{path}:"
      logger.error "#{e.class.name}: #{e.message}"

      case File.extname(path)
      when ".js"
        # Re-throw JavaScript asset exceptions to the browser
        logger.info "#{msg} 500 Internal Server Error\n\n"
        return javascript_exception_response(e)
      when ".css"
        # Display CSS asset exceptions in the browser
        logger.info "#{msg} 500 Internal Server Error\n\n"
        return css_exception_response(e)
      else
        raise
      end
    end
  end
end