Net ssh users - Oct 2008 - Requesting shell channel using net-ssh2

Looks like I was able to answer my own question again... appears the below
works. The only trick was that I had to make sure to properly exit the shell
(thus the exit, exit, y below) because otherwise the program sits and hangs
forever.

Still would be nice if someone was able to implement a "shell" state
machine to add a layer of abstraction, but I think this might do the trick for
me for now.

-Kevin


#!/usr/bin/ruby

require ''net/ssh''

Net::SSH.startmyhostname, myusername, :password=>mypassword) do |ssh|

    ssh.open_channel do |channel|
      channel.request_pty do |pty, success|
        if success #pty
          puts "pty successfully obtained"
          pty.send_channel_request "shell" do |sh, success|
            if success #sh
              puts "user shell started successfully"
###This is where I start inserting commands I want to run
              channel.send_data "\n" #get a prompt
              channel.send_data "no page\n" #disable paging
              channel.send_data "help\n" #example command that
produces output
              channel.send_data "exit\n"
              channel.send_data "exit\n"
              channel.send_data "y"  #confirm exit "y/n"
prompt
###After this last command completes, I want the script to exit.
              sh.on_data do |ch, data|
                print data
              end #on_data
              sh.on_extended_data do |ch, type, data|
                puts "got stderr: #{data}"
              end #on_extended_data
              sh.on_close do |ch|
                puts "channel is closing!"
              end #on_close
              sh.on_eof do |ch|
                puts "eof received!"
                channel.close
              end #on_eof
            else
              puts "could not start user shell"
            end #if success sh
          end #pty send_channel_request shell do
        else
          puts "could not obtain pty"
        end #if success pty
      end #channel request_pty do
    end #open_channel

    ssh.loop

end #ssh.start

From: Worth, Kevin
Sent: Tuesday, October 28, 2008 4:52 PM
To: ''net-ssh-users at rubyforge.org''
Subject: Requesting shell channel using net-ssh2

A network device I''m trying to use net-ssh to script doesn''t
seem to support the "exec" call. When I tried to request a shell (I
pulled the example from the "send_channel_request" rdoc), I got the
message that I had to request a pty first. This led me to the below code, which
is mostly pulled from examples in the rdoc. This code logs into the device, and
appears to start a shell successfully, but it then loops forever because in my
"on_data" callback, I have a "send_data" call. Am I going
about this in any way that resembles correctness?

Would sure be nice if a full "shell" capability were available like in
1.x or else the examples contained enough information that making a shell-like
environment in which you have all the control you needed was easy. Something
like the two examples in http://net-ssh.rubyforge.org/ssh/v1/chapter-5.html#s2
would be really helpful.

-Kevin


require ''net/ssh''

Net::SSH.start(myhostname, myusername,
:password=>mypassword,:verbose=>:info) do |ssh|

  ssh.open_channel do |channel|

  channel.request_pty do |pty, success|
    if success
      puts "pty successfully obtained"
    else
      puts "could not obtain pty"
    end
  end

    channel.send_channel_request "shell" do |sh, success|
        if success
          puts "user shell started successfully"
        else
          puts "could not start user shell"
      end
    end

      channel.on_data do |ch, data|
        puts "got stdout: #{data}"
        channel.send_data "\n"
      end

      channel.on_extended_data do |ch, type, data|
        puts "got stderr: #{data}"
      end

      channel.on_close do |ch|
        puts "channel is closing!"
      end

    channel.send_data("\nhelp")

  end
  ssh.loop

end
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