Ruby: Ping.pingecho missing

Question

Ruby used to have a Ping.pingecho method, but it seems as if (and the Ping module) have disappeared sometime:

% rvm use 1.8.7
Using ~/.rvm/gems/ruby-1.8.7-p334
% ruby -rping -e 'p Ping.pingecho "127.0.0.1"'
true
% rvm use 1.9.2
Using ~/.rvm/gems/ruby-1.9.2-p180
% ruby -rping -e 'p Ping.pingecho "127.0.0.1"'
<internal:lib/rubygems/custom_require>:29:in `require': no such file to load -- ping (LoadError)
        from <internal:lib/rubygems/custom_require>:29:in `require'
% ruby -e 'p Ping.pingecho "127.0.0.1"'
-e:1:in `<main>': uninitialized constant Object::Ping (NameError)

Has it moved to a different library (so what should I require to load it?), or has it been deleted, and replaced with a different module (so what should I use to determine whether a IP is reachable?).

Answer 1

Don know why or where it has gone. Rails still has a Ping class. A slight adaptation (to use a class method) would be:

require 'timeout'
require 'socket'

class Ping 
  def self.pingecho(host, timeout=5, service="echo")
    begin
      timeout(timeout) do
        s = TCPSocket.new(host, service)
        s.close
      end
    rescue Errno::ECONNREFUSED
      return true
    rescue   Timeout::Error, StandardError 
      return false 
    end
    return true
  end
end

p Ping.pingecho("127.0.0.1") #=> true
p Ping.pingecho("localhost") #=> true

Answer 2

I just encountered this issue. I settled with the net-ping gem as a replacement. It has a clear TCP ping example in gems/net-ping-1.7.7/examples/example_pingtcp.rb:

p1 = Net::Ping::TCP.new(good, 'http')
p p1.ping?

The rubydoc.info link at the time of this writing is not working, but here is a useful comment in the source of the module (tcp.rb)

# This method attempts to ping a host and port using a TCPSocket with
# the host, port and timeout values passed in the constructor.  Returns
# true if successful, or false otherwise.

So I swapped this:

return Ping.pingecho(server, 5, 22)

With this:

p = Net::Ping::TCP.new(server, 22, 5)
p.ping?

There are two caveats in moving from the old to the new equivalent module:

1. The arguments to the constructor are reversed (port and timeout)
2. The actual invocation of a ping is accomplished by calling the ping? method, rather than just instantiating.