[SOLVED] Why can't ruby open a TCPSocket on my Fedora 20 box?

Issue

I'm on Fedora 20 and use ruby 2.1.0. I've the following code from rel="nofollow">ruby-doc.

require 'socket'

s = TCPSocket.new 'localhost', 2000

while line = s.gets # Read lines from socket
  puts line         # and print them
end

s.close             # close socket when done

Ruby throws the following error:

client.rb:3:in `initialize': Connection refused - connect(2) for "localhost" port 2000     (Errno::ECONNREFUSED)
    from client.rb:3:in `new'
    from client.rb:3:in `<main>'

What could be the reason for this failure? I mean, the code should definitively work, it's dead simple and from a recognized tutorial web page for ruby. I guess that the problem is my operating system, but how do I get it working properly?

Solution

Sockets are the endpoints of a bidirectional communications channel. Sockets may communicate within a process, between processes on the same machine, or between processes on different continents.
A Simple Client:

require 'socket'      # Sockets are in standard library

hostname = 'localhost'
port = 2000

s = TCPSocket.open(hostname, port)

while line = s.gets   # Read lines from the socket
  puts line.chop      # And print with platform line terminator
end
s.close    

Now call TCPServer.open hostname, port function to specify a port for your service and create a TCPServer object.
A Simple Server:

require 'socket'               # Get sockets from stdlib

server = TCPServer.open(2000)  # Socket to listen on port 2000
loop {                         # Servers run forever
  client = server.accept       # Wait for a client to connect
  client.puts(Time.now.ctime)  # Send the time to the client
  client.puts "Closing the connection. Bye!"
  client.close                 # Disconnect from the client
}

read doc

Answered By - Зелёный

Answer Checked By - Terry (WPSolving Volunteer)