class Net::SSH::Telnet
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.
Constants
- CR
- EOL
- LF
- VERSION
Attributes
The ssh session and channel we are using.
The ssh session and channel we are using.
Public Class Methods
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 toNet::SSH
- also the default value forwaitfor
(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 toprint
.(Default:LF
) -
"PTY"
- If true a real Pty is allocated (ssh -T) otherwise only a shell is requested (Default: true) -
"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 existingNet::SSH
object forNet::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) -
"PTYOptions"
- A hash to be passed to Net::SSH::Connection::Channel#request_pty. See Net::SSH::Connection::Channel::VALID_PTY_OPTIONS for valid options.
# File lib/net/ssh/telnet.rb, line 160 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") @options["PTY"] = true unless @options.has_key?("PTY") @options["PTYOptions"] = {} unless @options.has_key?("PTYOptions") 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") opts = { :host_name => @options["Host"], # ignored :port => @options["Port"], # ignored :user => @options["Username"], :password => @options["Password"], :timeout => @options["Timeout"], :proxy => TinyFactory.new(@options["Proxy"]) }.delete_if { |_,v| v.nil? } @ssh = Net::SSH.start(nil, nil, opts) @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 opts = { :host_name => @options["Host"], :port => @options["Port"], :user => @options["Username"], :password => @options["Password"], :timeout => @options["Timeout"], :proxy => @options["Factory"] }.delete_if { |_,v| v.nil? } @ssh = Net::SSH.start(nil, nil, opts) @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 } if @options["PTY"] channel.request_pty(@options["PTYOptions"]) { |ch,success| if success == false raise "Failed to open ssh pty" end } 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
Public Instance Methods
Turn newline conversion on (mode
== false) or off (mode
== true), or return the current value (mode
is not specified).
# File lib/net/ssh/telnet.rb, line 297 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
Turn newline conversion on (false) or off (true).
# File lib/net/ssh/telnet.rb, line 309 def binmode=(mode) if (true == mode or false == mode) @options["Binmode"] = mode else raise ArgumentError, "argument must be true or false" end end
Close the ssh channel, and also the entire ssh session if we opened it.
# File lib/net/ssh/telnet.rb, line 286 def close @channel.close if @channel @channel = nil @ssh.close if @close_all and @ssh end
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 theputs
method. -
"Match"
- Passed towaitfor
as the “Prompt” parameter. See its defintion for details. -
"Timeout"
- Passed towaitfor
see its definition for details -
"FailEOF"
- Passed towaitfor
see its definition for details
# File lib/net/ssh/telnet.rb, line 460 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
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.
# File lib/net/ssh/telnet.rb, line 416 def print(string) terminator = @options["Terminator"] if @options["Binmode"] self.write(string) else self.write(string.gsub(/\n/n, terminator)) end end
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
# File lib/net/ssh/telnet.rb, line 429 def prompt= val @options["Prompt"] = val end
Sends string
to the host.
Same as print()
, but appends a newline to the string.
# File lib/net/ssh/telnet.rb, line 436 def puts(string) self.print(string + "\n") end
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)
# File lib/net/ssh/telnet.rb, line 332 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
to the host.
Does not perform any conversions on string
. Will log string
to the dumplog, if the Dump_log option is set.
# File lib/net/ssh/telnet.rb, line 403 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
Private Instance Methods
# File lib/net/ssh/telnet.rb, line 484 def _process_ssh begin @channel.connection.process(0) rescue IOError @eof = true end end