为什么不能在我的Fedora 20盒子上打开TCPSocket？

Question

我在Fedora 20上使用ruby 2.1.0.我从ruby-doc获得以下代码.

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抛出以下错误:

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>'

这次失败的原因是什么？我的意思是,代码应该明确地工作,它很简单,并且来自一个公认的ruby教程网页.我想这个问题是我的操作系统,但我怎样才能让它正常工作？

Answer 1

套接字是双向通信信道的端点.套接字可以在进程内,同一台机器上的进程之间或不同大洲的进程之间进行通信.
一个简单的客户:

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    

现在调用TCPServer.open hostname,port函数指定服务的端口并创建TCPServer对象.
简单的服务器:

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
}

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