Password Complexity

password_complexity.rb

# Regular expression to require the following
# Thanks to Scott Chamberlain on Stack Overflow
# http://stackoverflow.com/questions/3721843
# All ASCII printing characters
# At least 8 characters in length
# At least 1 lowercase letter
# At least 1 uppercase letter
# At least 1 special character
# No white-space characters
# At least 1 number

requirements = /(?=^[!-~]{8,}$)(?=.*[a-z])(?=.*[A-Z])(?=.*[^A-Za-z0-9])(?=^.*[^\s].*$)(?=.*[\d]).*$/

[ 
  "passwor",    # not long enough
  "P@SSWORD2",  # no lowercase letter
  "p@ssword2",  # no capital letter
  "Password2",  # no special character
  "P @ssword2", # whitespace
  "P_ssword",   # no number
  "P_ssword2"   # underscores as valid 'special character'
].each do |password|
  message = password[requirements].nil? ? "not ok" : "ok"
  puts "#{password} #{message}"
end

#=> passwor not ok
#=> P@SSWORD2 not ok
#=> p@ssword2 not ok
#=> Password2 not ok
#=> P @ssword2 not ok
#=> P_ssword not ok
#=> P_ssword2 ok