From: Rick DeNatale <rick.denatale@...>
Date: 2006-09-21T09:17:18+09:00
Subject: Re: piping input when shelling out

On 9/19/06, ara.t.howard@noaa.gov <ara.t.howard@noaa.gov> wrote:

> you're making it pretty hard on yourself:
>
>      harp:~ > cat a.rb
>      cat = IO.popen 'cat', 'r+'

Interestingly, I just found a use for popen this morning. I was
playing around with letting open-uri use an 'scp' url.

This is a complete hack based on the URI::HTTP class, and it's pretty
rudimentary.  Even though it's an 'scp' uri, it uses ssh internally.

As far as I can tell, without looking too hard, open-uri only supports
opening a URI for reading.

rick@frodo:/public/rubyscripts$ cat uris/scp.rb
#
# = uri/scp.rb
#
# Author:: Rick DeNatale
# License:: You can redistribute it and/or modify it under the same
term as Ruby.
#

require 'uri/generic'

module URI


  # scp_URI = "scp://" [ userinfo "@" ] host [ ":" port ]
  #      [ ; parameter = value ] [ abs_path ]


  class SCP < Generic
    DEFAULT_PORT = 22

    COMPONENT = [
      :scheme,
      :userinfo, :host, :port,
      :path
    ].freeze

    #
    # == Description
    #
    # Create a new URI::SCP object from components of URI::SCP with
    # check.  It is scheme, userinfo, host, port, and path. It
provided by an Array of a Hash.
    #
    def self.build(args)
      tmp = Util::make_components_hash(self, args)
      return super(tmp)
    end

    #
    # == Description
    #
    # Create a new URI::SCP object from ``generic'' components with no
    # check.
    #
    def initialize(*arg)
      super(*arg)
    end

    def ssh_command
      result = ["ssh "]
      result << "-p" + port.to_s + " " unless port == 22
      result << user + "@" if user
      result << host + " cat ~"
      result << path
      result.join('')
    end

    def open(&b)
      IO.popen(ssh_command, &b)
    end
  end

  @@schemes['SCP'] = SCP
end


-- 
Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/