Ruby implementation of null file (like /dev/null on Un*x, NUL on Windows) The newest version is available by "gem install devnull". See also: http://github.com/maraigue/devnull

devnull.rb

# NOTE:
# This version is out-of-date.
# Please access http://github.com/maraigue/devnull for the versions under development.

# Ruby implementation of null file (like /dev/null on Un*x, NUL on Windows)
# (C) 2010- H.Hiro(Maraigue) [email protected]
#
# DevNull works like an IO object. For example:
#   dn = DevNull.new
#   dn.puts "foo" # => nil (do nothing)
#   dn.gets       # => nil
#   dn.read       # => ""

require "enumerator"

class DevNull
  def initialize
    # do nothing
  end
  
  # methods that do nothing
  def <<(obj); end
  def close; end
  def close_read; end
  def close_write; end
  def fileno; end
  def print(*args); end
  def printf(*args); end
  def putc(*args); end
  def puts(*args); end
  def seek(*args); end
  def syswrite(*args); end
  def ungetbyte(*args); end
  def ungetc(*args); end
  def write(*args); end
  
  # methods that do nothing and returns something
  def getc; nil; end
  def getbyte; nil; end
  def gets(*args); nil; end
  def path; nil; end
  def pid; nil; end
  
  def binmode; self; end
  def flush; self; end
  def reopen(*args); self; end
  def set_encoding(*args); self; end
  
  def eof; true; end
  def eof?; true; end
  def sync; true; end
  
  def closed_read?; false; end
  def closed_write?; false; end
  def isatty; false; end
  def tty?; false; end
  
  def fsync; 0; end
  def pos; 0; end
  def tell; 0; end
  def rewind; 0; end
  
  def readlines(*args); []; end
  
  def sync=(arg); arg; end
  def truncate(arg); arg; end
  
  def each(*args); (block_given? ? self : [].to_enum); end
  alias :each_line :each
  alias :each_byte :each
  def external_encoding; "US-ASCII"; end
  def internal_encoding; "US-ASCII"; end
  def fcntl; raise NotImplementedError; end
  def readchar; raise EOFError; end
  def readbyte; raise EOFError; end
  def readline(*args); raise EOFError; end
  
  def read(len = 0, outbuf = nil)
    outbuf.replace("") if outbuf != nil
    (len.to_i == 0 ? "" : nil)
  end
  alias :sysread :read
  alias :readpartial :read
end

This script is what I have needed!

Thanks!

There remains some problem, e.g. this DevNull object can be used even if "close"d.

Writing after close is only an issue if you're testing to make sure your app acts sanely. Any code that does so is broken.

From what i hear, though, << should return self so that insertions can be chained. Otherwise, stream << "Oops\n" << "this breaks".

The first point, file closing, is just because I could not imagine its importance you have indicated.
I will try implementing it.

The second point, << method, is fixed in newly created repository (ordinary github rather than Gist).
http://github.com/maraigue/devnull
I'm sorry I have not lead you to the page of the new version in this Gist page.