How to use getoptlong class in ruby?

Question

I need help using getoptlong class in Ruby. I need to execute command prog_name.ruby -u -i -s filename. So far I can only execute it with prog_name.ruby -u filename -i filename -s filename.

This is my getoptlong code:

require 'getoptlong'

class CommonLog
parser = GetoptLong.new
parser.set_options(["-h", "--help", GetoptLong::NO_ARGUMENT],
                   ["-u", "--url",  GetoptLong::NO_ARGUMENT],
                   ["-i", "--ip",   GetoptLong::NO_ARGUMENT],
                   ["-s", "--stat", GetoptLong::NO_ARGUMENT])

begin
  begin
      opt,arg = parser.get_option
      break if not opt

      case opt
         when "-h" || "--help"
           puts "Usage: -u  filename"
           puts "Usage: -i  filename"
           puts "Usage: -s  filename"
         exit
         when "-u" || "--url"
            log = CommonLog.new(ARGV[0])
            log.urlReport
         when "-i" || "--ip"
            log = CommonLog.new(ARGV[0])
            log.ipReport
         when "-s" || "--stat"
            log = CommonLog.new(ARGV[0])
            log.statReport
         end
      rescue => err
         puts "#{err.class()}: #{err.message}"
         puts "Usage: -h -u -i -s filename"
      exit
   end
end while 1

if ARGV[0] == nil || ARGV.size != 1
   puts "invalid! option and filename required"
   puts "usage: -h -u -i -s filename"
end

Answer 1

I'm going to answer by recommending looking at the new-ish "slop" gem. It's a wrapper around getoptlong.

You can use gem install slop if you're using RVM, or sudo gem install slop otherwise.

GetOptLong is very powerful but, though I've used it several times, I still have to go review the docs each time.

If you want a bit more power, with an "easier to use interface than GetOptLong", look into Ruby's OptionParser. You'll need to work out the logic better, but this is a quick pass converting your code. I had to stub out a class for the CommonLog gem because I don't use it. The important stuff follows the line pulling log from ARGV:

require 'optparse'

class CommonLog
  def initialize(*args); end
  def urlReport();     puts "running urlReport()";        end
  def ipReport();      puts "running ipReport()";         end
  def statReport(arg); puts "running statReport(#{arg})"; end
end

log = CommonLog.new(ARGV[0])

OptionParser.new { |opts|
  opts.banner = "Usage: #{File.basename($0)} -u -i -s filename"

  opts.on( '-u', '--[no-]url', 'some short text describing URL') do
    log.urlReport()
  end

  opts.on('-i', '--[no-]ip', 'some short text describing IP') do
    log.ipReport()
  end

  opts.on('-s', '--stat FILENAME', 'some short text describing STAT') do |arg|
    log.statReport(arg)
  end
}.parse!

Also, as a quick critique, you are not writing idiomatic Ruby code:

• when statements can be written: when "-h", "--help"
• if ARGV[0] == nil || ARGV.size != 1 is convoluted. Study up on how ARGV and arrays work. Normally, for ARGV[0] to be nil there will be no more arguments, so ARGV.empty? would probably suffice.