如何在Rails应用程序中使用RubyGems类

Question

I need to stream a TAR file using data from the database in a Rails app. I know that RubyGems has the TarWriter module that suits my use case perfectly.

The question is, how can I include the module in my Rails app? I tried to require rubygems/package as follows:

require 'zlib'
require 'rubygems/package'

tar = StringIO.new

Gem::Package::TarWriter.new(tar) do |writer|
    writer.add_file("a_file.txt", 0644) do |f| 
        (1..1000).each do |i| 
            f.write("some text\n")
        end
    end
    writer.add_file("another_file.txt", 0644) do |f| 
        f.write("some more text\n")
    end
end
tar.seek(0)

gz = Zlib::GzipWriter.new(File.new('this_is_a_tar_gz.tar.gz', 'wb'))
gz.write(tar.read)
tar.close
gz.close

The require failed on the controller. I tried to adding gem 'rubygems/package' on my Gemfile but it didn't work.

It's a noob question, how can I use RubyGems modules from a Rails app?

Answer 1

您应该指定模块的完整路径： Gem::Package::TarWriter并向控制器添加Gem::Package::TarWriter require 'rubygems/package' 。