#!/bin/env ruby
require 'cgi'

## Ruby metaprogramming challenge
#
# Remember CGI scripts?

flag = 'IGCTF{de056a6b-c4e2-4e21-8c2c-ccdac5340c6d}'

cgi = CGI.new

method = cgi['method']
args = cgi.params['args']

cgi.out { <<-HTML }
<style>
  head,title {
    display: block;
    font-family: monospace;
  }
  title {
    font-size: 32pt;
  }
  pre {
    display: none;
  }
</style>
<title>Challenge</title>
<pre>
#{
if method && !method.empty?
  unless %w(system send eval public_send exec instance_eval).include? method
    Object.new.send(method, *args)
  end
end
}
#{
open(__FILE__) do |f|
  CGI.escapeHTML(f.read.gsub(flag, 'FLAGGY_WAGGY_UWU'))
end
}
</pre>
HTML