在 get() 中从 Ruby 中损坏的 TCP 套接字中恢复 [英] Recovering from a broken TCP socket in Ruby when in gets()

问题描述

我正在读取 TCP 套接字上的输入行，类似于:

I'm reading lines of input on a TCP socket, similar to this:

class Bla  
  def getcmd
    @sock.gets unless @sock.closed?
  end

  def start     
    srv = TCPServer.new(5000)
    @sock = srv.accept
    while ! @sock.closed?
      ans = getcmd
    end
  end
end

如果端点在 getline() 运行时终止连接，则 gets() 挂起.

If the endpoint terminates the connection while getline() is running then gets() hangs.

我该如何解决这个问题?是否有必要做非阻塞或定时 I/O?

How can I work around this? Is it necessary to do non-blocking or timed I/O?

推荐答案

您可以使用 select 来查看是否可以安全地从套接字获取，请参阅以下使用此技术实现的 TCPServer.

You can use select to see whether you can safely gets from the socket, see following implementation of a TCPServer using this technique.

require 'socket'

host, port = 'localhost', 7000

TCPServer.open(host, port) do |server|
  while client = server.accept
    readfds = true
    got = nil
    begin
      readfds, writefds, exceptfds = select([client], nil, nil, 0.1)
      p :r => readfds, :w => writefds, :e => exceptfds

      if readfds
        got = client.gets 
        p got
      end
    end while got
  end
end

这里是一个试图破坏服务器的客户端:

And here a client that tries to break the server:

require 'socket'

host, port = 'localhost', 7000

TCPSocket.open(host, port) do |socket|
  socket.puts "Hey there"
  socket.write 'he'
  socket.flush
  socket.close
end

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