module S3Proxy

# File lib/s3proxy.rb, line 6
def proxy_s3_file(bucket, key)
  cached_file = cache_location(bucket, key)

  options = {
    bucket: bucket,
    key: key,
  }
  options[:if_modified_since] = File.mtime(cached_file) if File.exists?(cached_file)

  begin
    s3object = s3.get_object(options, target: cached_file)
  rescue Aws::S3::Errors::NotModified
    options.delete(:if_modified_since)
    s3object = s3.head_object(options)
  end
  File.new cached_file
end

# File lib/s3proxy.rb, line 25
def cache_location(bucket, key)
  hash = Digest::MD5.hexdigest "#{bucket}/#{key}"
  path = "#{Dir.tmpdir}/s3proxy-#{Process.pid}"
  Dir.mkdir(path, 0700) unless File.exists?(path)
  "#{path}/#{hash}"
end

# File lib/s3proxy.rb, line 33
def s3
  @s3 ||= Aws::S3::Client.new
end