I have the following code:
#!/usr/bin/ruby
require 'socket'
server = '221.186.184.68'
if ( server =~ /^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/ )
hostname = Socket.gethostbyaddr(server.split(".").map(&:to_i).pack("CCCC")).first
puts hostname
end
All well, but when I input an IP Address that doesn't reverse I get exeception error:
i.rb:8:in `gethostbyaddr': host not found (SocketError)
from i.rb:8
How can I hide the message? Thanks!
use exception handling
#!/usr/bin/ruby
require 'socket'
server = '221.186.184.68'
begin
if ( server =~ /^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/ )
hostname = Socket.gethostbyaddr(server.split(".").map(&:to_i).pack("CCCC")).first
puts hostname
end
rescue => err
#puts "I don't want to print this #{err.message}. Hence commented"
end
Related
i have the following code
require 'socket'
def connect(socket)
while line = socket.gets # Read lines from socket
puts line # and print them
end
socket.close # close socket when done
end
def serve(server)
loop do
client = server.accept # Wait for a client to connect
client.puts "Hello !"
client.puts "Time is #{Time.now}"
client.close
end
end
if ARGV[0] == "-s"
ip_port = ARGV[1]
server = TCPServer.new ip_port
serve(server)
elsif ARGV.length == 2
ip_address = ARGV[0]
ip_port = ARGV[1]
puts ip_address
puts ip_port
socket = TCPSocket.new ip_address , ip_port
connect(socket)
else
puts "PLease enter an IP address and IP port"
end
The code above is a basic server and client. use the -s flag to tell the program to act like a server.
This code works when I use localhost as a address but does not work when I use 127.0.0.1 as the address. I receive a No connection could be made because the target machine actively refused it. - connect(2) error when i use 127.0.0.1. was wondering if anyone knows what the problem is.
I don't think there's anything wrong with the code itself, this looks like more of an issue due to firewall settings or perhaps something else on the machine.
You could always try opening the port and then attempting to telnet into it from a different terminal telnet 127.0.0.1 port. You can also use netstat -atun to check if the port is indeed open and to which address it is bound (0.0.0.0 means accessible by all IP addresses).
I have been trying to get port forwarding to work correctly with Net::SSH. From what I understand I need to fork out the Net::SSH session if I want to be able to use it from the same Ruby program so that the event handling loop can actually process packets being sent through the connection. However, this results in the ugliness you can see in the following:
#!/usr/bin/env ruby -w
require 'net/ssh'
require 'httparty'
require 'socket'
include Process
log = Logger.new(STDOUT)
log.level = Logger::DEBUG
local_port = 2006
child_socket, parent_socket = Socket.pair(:UNIX, :DGRAM, 0)
maxlen = 1000
hostname = "www.example.com"
pid = fork do
parent_socket.close
Net::SSH.start("hostname", "username") do |session|
session.logger = log
session.logger.sev_threshold=Logger::Severity::DEBUG
session.forward.local(local_port, hostname, 80)
child_socket.send("ready", 0)
pidi = fork do
msg = child_socket.recv(maxlen)
puts "Message from parent was: #{msg}"
exit
end
session.loop do
status = waitpid(pidi, Process::WNOHANG)
puts "Status: #{status.inspect}"
status.nil?
end
end
end
child_socket.close
puts "Message from child: #{parent_socket.recv(maxlen)}"
resp = HTTParty.post("http://localhost:#{local_port}/", :headers => { "Host" => hostname } )
# the write cannot be the last statement, otherwise the child pid could end up
# not receiving it
parent_socket.write("done")
puts resp.inspect
Can anybody show me a more elegant/better working solution to this?
I spend a lot of time trying to figure out how to correctly implement port forwarding, then I took inspiration from net/ssh/gateway library. I needed a robust solution that works after various possible connection errors. This is what I'm using now, hope it helps:
require 'net/ssh'
ssh_options = ['host', 'login', :password => 'password']
tunnel_port = 2222
begin
run_tunnel_thread = true
tunnel_mutex = Mutex.new
ssh = Net::SSH.start *ssh_options
tunnel_thread = Thread.new do
begin
while run_tunnel_thread do
tunnel_mutex.synchronize { ssh.process 0.01 }
Thread.pass
end
rescue => exc
puts "tunnel thread error: #{exc.message}"
end
end
tunnel_mutex.synchronize do
ssh.forward.local tunnel_port, 'tunnel_host', 22
end
begin
ssh_tunnel = Net::SSH.start 'localhost', 'tunnel_login', :password => 'tunnel_password', :port => tunnel_port
puts ssh_tunnel.exec! 'date'
rescue => exc
puts "tunnel connection error: #{exc.message}"
ensure
ssh_tunnel.close if ssh_tunnel
end
tunnel_mutex.synchronize do
ssh.forward.cancel_local tunnel_port
end
rescue => exc
puts "tunnel error: #{exc.message}"
ensure
run_tunnel_thread = false
tunnel_thread.join if tunnel_thread
ssh.close if ssh
end
That's just how SSH in general is. If you're offended by how ugly it looks, you should probably wrap up that functionality into a port forwarding class of some sort so that the exposed part is a lot more succinct. An interface like this, perhaps:
forwarder = PortForwarder.new(8080, 'remote.host', 80)
So I have found a slightly better implementation. It only requires a single fork but still uses a socket for the communication. It uses IO#read_nonblock for checking if a message is ready. If there isn't one, the method throws an exception, in which case the block continues to return true and the SSH session keeps serving requests. Once the parent is done with the connection it sends a message, which causes child_socket.read_nonblock(maxlen).nil? to return false, making the loop exit and therefore shutting down the SSH connection.
I feel a little better about this, so between that and #tadman's suggestion to wrap it in a port forwarding class I think it's about as good as it'll get. However, any further suggestions for improving this are most welcome.
#!/usr/bin/env ruby -w
require 'net/ssh'
require 'httparty'
require 'socket'
log = Logger.new(STDOUT)
log.level = Logger::DEBUG
local_port = 2006
child_socket, parent_socket = Socket.pair(:UNIX, :DGRAM, 0)
maxlen = 1000
hostname = "www.example.com"
pid = fork do
parent_socket.close
Net::SSH.start("ssh-tunnel-hostname", "username") do |session|
session.logger = log
session.logger.sev_threshold=Logger::Severity::DEBUG
session.forward.local(local_port, hostname, 80)
child_socket.send("ready", 0)
session.loop { child_socket.read_nonblock(maxlen).nil? rescue true }
end
end
child_socket.close
puts "Message from child: #{parent_socket.recv(maxlen)}"
resp = HTTParty.post("http://localhost:#{local_port}/", :headers => { "Host" => hostname } )
# the write cannot be the last statement, otherwise the child pid could end up
# not receiving it
parent_socket.write("done")
puts resp.inspect
I have to take a dump of a service in sinatra and display it in the content area of the webpage.
The Service I have to access via code runs on server at port 6557. It doesnt use any encryption or authentication. Its a plain readonly request response thingy like http.
Here is what works in teminal
$ echo "GET hosts" | nc 192.168.1.1 6557
gives me the intended output. I need to do something similar using the sinatra application.
I wrote this code but is grossly incorrect. Can sombody help me with code or lookup materials or examples.
get '/' do
host = "192.168.1.1"
port = 6557
dat = ""
#socket = TCPSocket.open (host, port)
while(true)
if(IO.select([],[],[#socket],0))
socket.close
return
end
begin
while( (data = #socket.recv_nonblock(100)) != "")
dat = dat+ data
end
rescue Errno::EAGAIN
end
begin
#str = "GET hosts"
#socket.puts(#str);
rescue Errno::EAGAIN
rescue EOFError
exit
end
IO.select([#socket], [#socket], [#socket])
end
#line = dat
erb :info
end
The code on execution just hangs up.
Also if possible please give some links to read up to get a conceptual context of the problem.
I think the Ruby equivalent to your shell command should be as simple as:
require "socket"
socket = TCPSocket.new "192.168.1.1", 6557
socket.puts "GET hosts"
socket.read
According to the docs, #read should close the socket automatically, so you don't need to worry about doing that manually.
You can execute shell commands directly from ruby using backticks or the system command. Something like this may work for you:
get "/" do
#line = `echo "GET hosts" | nc 192.168.1.1 6557`
erb :info
end
Check out the ruby docs for Kernel#system for more info.
I'm running a simple thin server, that publish some messages to different queues, the code looks like :
require "rubygems"
require "thin"
require "amqp"
require 'msgpack'
app = Proc.new do |env|
params = Rack::Request.new(env).params
command = params['command'].strip rescue "no command"
number = params['number'].strip rescue "no number"
p command
p number
AMQP.start do
if command =~ /\A(create|c|r|register)\z/i
MQ.queue("create").publish(number)
elsif m = (/\A(Answer|a)\s?(\d+|\d+-\d+)\z/i.match(command))
MQ.queue("answers").publish({:number => number,:answer => "answer" }.to_msgpack )
end
end
[200, {'Content-Type' => "text/plain"} , command ]
end
Rack::Handler::Thin.run(app, :Port => 4001)
Now when I run the server, and do something like http://0.0.0.0:4001/command=r&number=123123123
I'm always getting duplicate outputs, something like :
"no command"
"no number"
"no command"
"no number"
The first thing is why I'm getting like duplicate requests ? is it something has to do with the browser ? since when I use curl I'm not having the same behavior , and the second thing why I can't get the params ?
Any tips about the best implementation for such a server would be highly appreciated
Thanks in advance .
The second request comes from the browser looking for the favicon.ico. You can inspect the requests by adding the following code in your handler:
params = Rack::Request.new(env).params
p env # add this line to see the request in your console window
Alternatively you could use Sinatra:
require "rubygems"
require "amqp"
require "msgpack"
require "sinatra"
get '/:command/:number' do
command = params['command'].strip rescue "no command"
number = params['number'].strip rescue "no number"
p command
p number
AMQP.start do
if command =~ /\A(create|c|r|register)\z/i
MQ.queue("create").publish(number)
elsif m = (/\A(Answer|a)\s?(\d+|\d+-\d+)\z/i.match(command))
MQ.queue("answers").publish({:number => number,:answer => "answer" }.to_msgpack )
nd
end
return command
end
and then run ruby the_server.rb at the command line to start the http server.
I have this code to check if the site is up or down:
require 'net/http'
require 'uri'
res = Net::HTTP.get_response(URI.parse('http://www.saddsdsds.com/'))
case res
when Net::HTTPSuccess, Net::HTTPRedirection
# OK
puts "ok"
else
puts "ok-error"
end
res2 = Net::HTTP.get_response(URI.parse('http://www.sads.com/'))
case res2
when Net::HTTPSuccess, Net::HTTPRedirection
# OK
puts "ok"
else
puts "ok-error"
end
However, the code works fine when the site is known but when the site is unknown (like the res example), the code breaks with this erorr:
`initialize': getaddrinfo: nodename nor servname provided, or not known (SocketError)
How can I fix this so when the address does not exist, the code does not break?
Also, is this the best way to check if a site is online?
Thanks
Surround all of that code with a begin..rescue block:
begin
...
rescue SocketError => e
puts "SocketError occurred: " + e
end