Manipulating Zip archives with Ruby 1.8.7 - ruby

Question

I'm relatively new to Ruby, and I have to use the version 1.8.7.
I have tried 'zip' and ended up with a cryptic stack trace while attempting to use the example from the docs. My script
#!/usr/bin/env ruby
require 'rubygems'
require 'zip'
require 'zip/zipfilesystem'
Zip::ZipFile.open("myfile.war") do |a|
puts a.file.read("META-INF/context.xml")
end
produces the following:
$./rzip.rb
/var/lib/gems/1.8/gems/zip-2.0.2/lib/zip/zip.rb:1137:in `dup': can't dup NilClass (TypeError)
from /var/lib/gems/1.8/gems/zip-2.0.2/lib/zip/zip.rb:1137:in `dup'
from /var/lib/gems/1.8/gems/zip-2.0.2/lib/zip/zip.rb:1137:in `map'
from /var/lib/gems/1.8/gems/zip-2.0.2/lib/zip/zip.rb:1137:in `dup'
from /var/lib/gems/1.8/gems/zip-2.0.2/lib/zip/zip.rb:1373:in `initialize'
from /var/lib/gems/1.8/gems/zip-2.0.2/lib/zip/zip.rb:1384:in `new'
from /var/lib/gems/1.8/gems/zip-2.0.2/lib/zip/zip.rb:1384:in `open'
from ./rzip.rb:7
What is wrong with my code? Or is it some version incompatibility issue? If it is not my blunder, what should I use for zip archives manipulations?

Answer 1

I can't reproduce your error although it seems you are not alone in this. Can I suggest using Zip::ZipFile. This is running on my system (Ubuntu 12.04 LTS):
require 'zip/zip'
Zip::ZipFile.open("my.zip", Zip::ZipFile::CREATE) {
|zipfile|
zipfile.get_output_stream("first.txt") { |f| f.puts "Hello from ZipFile" }
zipfile.mkdir("a_dir")
}
You can also see see some good examples/usage of Zip::ZipFile on GitHub