Class: Net::SSH::Telnet

Inherits:
Object
  • Object
show all
Defined in:
lib/net/ssh/telnet.rb,
lib/net/ssh/telnet/version.rb

Overview

Net::SSH::Telnet

Provides a simple send/expect interface with an API almost identical to Net::Telnet. Please see Net::Telnet for main documentation. Only the differences are documented here.

Defined Under Namespace

Classes: TinyFactory

Constant Summary collapse

CR = 
"\015"
LF = 
"\012"
EOL = 
CR + LF
VERSION = 
'0.2.0'

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options, &blk) ⇒ Telnet

Creates a new Net::SSH::Telnet object.

The API is similar to Net::Telnet, although you will need to pass in either an existing Net::SSH::Session object or a Username and Password, as shown below.

Note that unlike Net::Telnet there is no preprocess method automatically setting up options related to proper character translations, so if your remote ptty is configured differently than the typical linux one you may need to pass in a different terminator or call ‘stty’ remotely to set it into an expected mode. This is better explained by the author of perl’s Net::SSH::Expect here:

search.cpan.org/~bnegrao/Net-SSH-Expect-1.04/lib/Net/SSH/Expect.pod #IMPORTANT_NOTES_ABOUT_DEALING_WITH_SSH_AND_PSEUDO-TERMINALS

though for most installs the default LF should be fine. See example 5 below.

A new option is added to correct a misfeature of Net::Telnet. If you pass “FailEOF” => true, then if the remote end disconnects while you are still waiting for your match pattern then an EOFError is raised. Otherwise, it reverts to the same behaviour as Net::Telnet, which is just to return whatever data was sent so far, or nil if no data was returned so far. (This is a poor design because you can’t tell whether the expected pattern was successfully matched or the remote end disconnected unexpectedly, unless you perform a second match on the return string). See blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-core/11373 blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-core/11380

Example 1 - pass existing Net::SSH::Session object

ssh = Net::SSH.start("127.0.0.1",
      :username=>"test123",
      :password=>"pass456"
)
s = Net::SSH::Telnet.new(
      "Dump_log" => "/dev/stdout",
      "Session" => ssh
)
puts "Logged in"
p s.cmd("echo hello")

This is the most flexible way as it allows you to set up the SSH session using whatever authentication system you like. When done this way, calling Net::SSH::Telnet.new multiple times will create multiple channels, and #close will only close one channel.

In all later examples, calling #close will close the entire Net::SSH::Session object (and therefore drop the TCP connection)

Example 2 - pass host, username and password

s = Net::SSH::Telnet.new(
        "Dump_log" => "/dev/stdout",
        "Host" => "127.0.0.1",
        "Username" => "test123",
        "Password" => "pass456"
)
puts "Logged in"
puts s.cmd("echo hello")

Example 3 - pass open IO object, username and password (this is really just for compatibility with Net::Telnet Proxy feature)

require 'socket'
sock = TCPSocket.open("127.0.0.1",22)
s = Net::SSH::Telnet.new(
        "Dump_log" => "/dev/stdout",
        "Proxy" => sock,
        "Username" => "test123",
        "Password" => "pass456"
)
puts "Logged in"
puts s.cmd("echo hello")

Example 4 - pass a connection factory, host, username and password; Net::SSH will call #open(host,port) on this object. Included just because it was easy :-)

require 'socket'
s = Net::SSH::Telnet.new(
        "Dump_log" => "/dev/stdout",
        "Factory" => TCPSocket,
        "Host" => "127.0.0.1",
        "Username" => "test123",
        "Password" => "pass456"
)
puts "Logged in"
puts s.cmd("echo hello")

Example 5 - connection to a SAN device running a customized NetBSD with different ptty defaults, it doesn’t convert LF -> CR+LF (see the man page for ‘stty’) and uses a custom prompt

s = Net::SSH::Telnet.new(
        "Host" => "192.168.1.1",
        "Username" => "test123",
        "Password" => "pass456",
        "Prompt" => %r{^\S+>\s.*$},
        "Terminator" => "\r"
)
puts "Logged in"
puts s.cmd("show alerts")

New objects take a option hash to set default settings. The keys for this options hash are all strings. A block can also be passed to constructor which will get executed after the first prompt is found.

Hash Parameters

  • "Host" - a string to define the hostname to connect to(Default: “localhost”)

  • "Port" - port number to connect to(Default: 22)

  • "Prompt" - a regular expression to define the the prompt to expect(Default: /[$%#>] z/n )

  • "Timeout" - the time out value passed on to Net::Ssh - also the default value for #waitfor(Default: 10)

  • "Waittime" - Max time to wait after a possible prompt it seen to make sure more data isn’t coming(Default: 0)

  • "Terminator" - This value is appended to all strings that are sent to #print.(Default: LF)

  • "Binmode" - Enable binary mode.(Default: false)

  • "Output_log" - A file name to open as an output log.

  • "Dump_log" - A file name to open to dump the entire session to.

  • "Session" - An existing Net::Ssh object for Net::Ssh::Telnet to use as its connection(See example 1)

  • "Proxy" - An open IO object to use as a Proxy(See example 3)

  • "Factory" - A connection factory to use to establish the connection. Net::Ssh::Telnet will call #open(host, post) on this object.(See example 4)



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# File 'lib/net/ssh/telnet.rb', line 157

def initialize(options, &blk) # :yield: mesg
  @options = options
  @options["Host"]       = "localhost"   unless @options.has_key?("Host")
  @options["Port"]       = 22            unless @options.has_key?("Port")
  @options["Prompt"]     = /[$%#>] \z/n  unless @options.has_key?("Prompt")
  @options["Timeout"]    = 10            unless @options.has_key?("Timeout")
  @options["Waittime"]   = 0             unless @options.has_key?("Waittime")
  @options["Terminator"] = LF            unless @options.has_key?("Terminator")

  unless @options.has_key?("Binmode")
    @options["Binmode"]    = false
  else
    unless (true == @options["Binmode"] or false == @options["Binmode"])
      raise ArgumentError, "Binmode option must be true or false"
    end
  end

  if @options.has_key?("Output_log")
    @log = File.open(@options["Output_log"], 'a+')
    @log.sync = true
    @log.binmode
  end

  if @options.has_key?("Dump_log")
    @dumplog = File.open(@options["Dump_log"], 'a+')
    @dumplog.sync = true
    @dumplog.binmode
    def @dumplog.log_dump(dir, x)  # :nodoc:
      len = x.length
      addr = 0
      offset = 0
      while 0 < len
        if len < 16
          line = x[offset, len]
        else
          line = x[offset, 16]
        end
        hexvals = line.unpack('H*')[0]
        hexvals += ' ' * (32 - hexvals.length)
        hexvals = format("%s %s %s %s  " * 4, *hexvals.unpack('a2' * 16))
        line = line.gsub(/[\000-\037\177-\377]/n, '.')
        printf "%s 0x%5.5x: %s%s\n", dir, addr, hexvals, line
        addr += 16
        offset += 16
        len -= 16
      end
      print "\n"
    end
  end

  if @options.has_key?("Session")
    @ssh = @options["Session"]
    @close_all = false
  elsif @options.has_key?("Proxy")
    @ssh = Net::SSH.start(nil, nil,
            :host_name => @options["Host"],  # ignored
            :port => @options["Port"],       # ignored
            :user => @options["Username"],
            :password => @options["Password"],
            :timeout => @options["Timeout"],
            :proxy => TinyFactory.new(@options["Proxy"])
    )
    @close_all = true
  else
    message = "Trying " + @options["Host"] + "...\n"
    yield(message) if block_given?
    @log.write(message) if @options.has_key?("Output_log")
    @dumplog.log_dump('#', message) if @options.has_key?("Dump_log")

    begin
      @ssh = Net::SSH.start(nil, nil,
            :host_name => @options["Host"],
            :port => @options["Port"],
            :user => @options["Username"],
            :password => @options["Password"],
            :timeout => @options["Timeout"],
            :proxy => @options["Factory"]
      )
      @close_all = true
    rescue TimeoutError
      raise TimeoutError, "timed out while opening a connection to the host"
    rescue
      @log.write($ERROR_INFO.to_s + "\n") if @options.has_key?("Output_log")
      @dumplog.log_dump('#', $ERROR_INFO.to_s + "\n") if @options.has_key?("Dump_log")
      raise
    end

    message = "Connected to " + @options["Host"] + ".\n"
    yield(message) if block_given?
    @log.write(message) if @options.has_key?("Output_log")
    @dumplog.log_dump('#', message) if @options.has_key?("Dump_log")
  end

  @buf = ""
  @eof = false
  @channel = nil
  @ssh.open_channel do |channel|
    channel.on_data { |ch,data| @buf << data }
    channel.on_extended_data { |ch,type,data| @buf << data if type == 1 }
    channel.on_close { @eof = true }
    channel.request_pty { |ch,success|
      if success == false
        raise "Failed to open ssh pty"
      end
    }
    channel.send_channel_request("shell") { |ch, success|
      if success
        @channel = ch
        waitfor(@options['Prompt'], &blk)
        return
      else
        raise "Failed to open ssh shell"
      end
    }
  end
  @ssh.loop
end

Instance Attribute Details

#channel ⇒ Object (readonly)

The ssh session and channel we are using.



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# File 'lib/net/ssh/telnet.rb', line 284

def channel
  @channel
end

#ssh ⇒ Object (readonly)

The ssh session and channel we are using.



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# File 'lib/net/ssh/telnet.rb', line 284

def ssh
  @ssh
end

Instance Method Details

#binmode(mode = nil) ⇒ Object

Turn newline conversion on (mode == false) or off (mode == true), or return the current value (mode is not specified).



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# File 'lib/net/ssh/telnet.rb', line 288

def binmode(mode = nil)
  case mode
  when nil
    @options["Binmode"]
  when true, false
    @options["Binmode"] = mode
  else
    raise ArgumentError, "argument must be true or false"
  end
end

#binmode=(mode) ⇒ Object

Turn newline conversion on (false) or off (true).



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# File 'lib/net/ssh/telnet.rb', line 300

def binmode=(mode)
  if (true == mode or false == mode)
    @options["Binmode"] = mode
  else
    raise ArgumentError, "argument must be true or false"
  end
end

#close ⇒ Object

Close the ssh channel, and also the entire ssh session if we opened it.



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# File 'lib/net/ssh/telnet.rb', line 277

def close
  @channel.close if @channel
  @channel = nil
  @ssh.close if @close_all and @ssh
end

#cmd(options) ⇒ Object

Sends a command to the host.

More exactly, sends a string to the host, and reads in all received data until is sees the prompt or other matched sequence.

The command or other string will have the newline sequence appended to it.

The options parameter takes a String or Hash. The Hash can be used to override the default settings that were established when the object was created.

A block can be provided to be called when the first prompt or “Match” is found.

Hash Parameters

  • "String" - This string is sent over the connection via the #puts method.

  • "Match" - Passed to #waitfor as the “Prompt” parameter. See its defintion for details.

  • "Timeout" - Passed to #waitfor see its definition for details

  • "FailEOF" - Passed to #waitfor see its definition for details



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# File 'lib/net/ssh/telnet.rb', line 451

def cmd(options) # :yield: recvdata
  match    = @options["Prompt"]
  time_out = @options["Timeout"]
  fail_eof = @options["FailEOF"]

  if options.kind_of?(Hash)
    string   = options["String"]
    match    = options["Match"]   if options.has_key?("Match")
    time_out = options["Timeout"] if options.has_key?("Timeout")
    fail_eof = options["FailEOF"] if options.has_key?("FailEOF")
  else
    string = options
  end

  self.puts(string)
  if block_given?
    waitfor({"Prompt" => match, "Timeout" => time_out, "FailEOF" => fail_eof}){|c| yield c }
  else
    waitfor({"Prompt" => match, "Timeout" => time_out, "FailEOF" => fail_eof})
  end
end

#print(string) ⇒ Object

Sends string to the host.

This does not automatically append a newline to the string. Embedded newlines may be converted depending upon the values of binmode or terminator.



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# File 'lib/net/ssh/telnet.rb', line 407

def print(string)
  terminator = @options["Terminator"]

  if @options["Binmode"]
    self.write(string)
  else
    self.write(string.gsub(/\n/n, terminator))
  end
end

#prompt=(val) ⇒ Object

Change the standard prompt This is useful if you need a special prompt value for initializing the session, but want to use a different prompt for the rest of the session



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# File 'lib/net/ssh/telnet.rb', line 420

def prompt= val
  @options["Prompt"] = val
end

#puts(string) ⇒ Object

Sends string to the host.

Same as #print(), but appends a newline to the string.



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# File 'lib/net/ssh/telnet.rb', line 427

def puts(string)
  self.print(string + "\n")
end

#waitfor(options) ⇒ Object

Read data from the host until a certain sequence is matched.

The options parameter takes an string keyed option Hash or a String.

A block can be provided to be called after the first prompt or match is found.

Hash Parameters

  • "Match" - Regular expression to match

  • "Prompt" - Regular expression to match (Same as “Match”)

  • "String" - String to match

  • "Timeout" - Max time in seconds that can pass between packets (Default: 10 - set to false for no timeout)

  • "Waittime" - Max time to wait after a possible prompt it seen to make sure more data isn’t coming(Default: 0)

  • "FailEOF" - Raise EOFError if EOF is reached on the connection.(Default: false)



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# File 'lib/net/ssh/telnet.rb', line 323

def waitfor(options) # :yield: recvdata
  time_out = @options["Timeout"]
  waittime = @options["Waittime"]
  fail_eof = @options["FailEOF"]

  if options.kind_of?(Hash)
    prompt   = if options.has_key?("Match")
                 options["Match"]
               elsif options.has_key?("Prompt")
                 options["Prompt"]
               elsif options.has_key?("String")
                 Regexp.new( Regexp.quote(options["String"]) )
               end
    time_out = options["Timeout"]  if options.has_key?("Timeout")
    waittime = options["Waittime"] if options.has_key?("Waittime")
    fail_eof = options["FailEOF"]  if options.has_key?("FailEOF")
  else
    prompt = options
  end

  if time_out == false
    time_out = nil
  end

  line = ''
  buf = ''
  rest = ''
  sock = @ssh.transport.socket

  until @ssh.transport.socket.available == 0 && @buf == "" && prompt === line && (@eof || (!sock.closed? && !IO::select([sock], nil, nil, waittime)))
    # @buf may have content if it was processed by Net::SSH before #waitfor
    # was called
    # The prompt is checked in case a waittime was specified, we've already
    # seen the prompt, but a protocol-level packet came through during the
    # above IO::select, causing us to reprocess
    if @buf == '' && (@ssh.transport.socket.available == 0) && !(prompt === line) && !IO::select([sock], nil, nil, time_out)
      raise Net::ReadTimeout, "timed out while waiting for more data"
    end
    _process_ssh
    if @buf != ""
      c = @buf; @buf = ""
      @dumplog.log_dump('<', c) if @options.has_key?("Dump_log")
      buf = rest + c
      rest = ''
      unless @options["Binmode"]
        if pt = buf.rindex(/\r\z/no)
          buf = buf[0 ... pt]
          rest = buf[pt .. -1]
        end
        buf.gsub!(/#{EOL}/no, "\n")
      end
      @log.print(buf) if @options.has_key?("Output_log")
      line += buf
      yield buf if block_given?
    elsif @eof # End of file reached
      break if prompt === line
      raise EOFError if fail_eof
      if line == ''
        line = nil
        yield nil if block_given?
      end
      break
    end
  end
  line
end

#write(string) ⇒ Object

Write string to the host.

Does not perform any conversions on string. Will log string to the dumplog, if the Dump_log option is set.



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# File 'lib/net/ssh/telnet.rb', line 394

def write(string)
  @dumplog.log_dump('>', string) if @options.has_key?("Dump_log")
  # Add string to Net:SSH output queue
  @channel.send_data string
  # Call single instance of Net::SSH loop to process output queue
  _process_ssh
end