How to use getoptlong class in ruby? - 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.

Answer 2

you have several errors in the sample program
#each and #get only return the first string in the option and convert the others to it.
You should put that check for arguments before the options processing
You probably don't want this in with your logging class
require 'getoptlong'
# don't pollute CommonLog with this
include CommonLog
# if this is the startup module
if __FILE__ == $0 then
# Check to ensure there are arguments
if ARGV.size < 1
puts "invalid! option and filename required"
puts "usage: -h -u -i -s filename"
end
# set up parser and get the options
parser_opts=GetoptLong.new(
["--help", "-h", GetoptLong::NO_ARGUMENT],
["--url", "-u", GetoptLong::NO_ARGUMENT],
["--ip", "-i", "--ip", GetoptLong::NO_ARGUMENT],
["--stat", "-s", GetoptLong::NO_ARGUMENT]
)
parser_opts.each do |opt,arg|
begin # this is for the exception processing
case opt
when "--help" #only the first option is returned read ruby doc on #each
puts "Usage: -u filename"
puts "Usage: -i filename"
puts "Usage: -s filename"
exit
when "--url" #only the first option is returned
log = CommonLog.new(ARGV[0])
log.urlReport
when "--ip" #only the first option is returned
log = CommonLog.new(ARGV[0])
log.ipReport
when "--stat" #only the first option is returned
log = CommonLog.new(ARGV[0])
log.statReport
else # this should not be used
puts "unexpected option %s"%opt
puts "Usage: -h -u -i -s filename"
end
rescue Exception => err #rescuing an unexpected Exception
puts "#{err.class()}: #{err.message}"
puts "Usage: -h -u -i -s filename"
Kernel.exit
end
end
end