Re: [PerlChina] 一个奇怪的问题

[Joe Jiang]

crlf?
可以用 telnet 来测试 echo

On 1/9/06, 黄叶 <hylinux at gmail.com> wrote:
>
> 我在看<perl网络编程》这本书是有下面一个例子。
> 分别是第四章和第五章的例子。
> 显示使用模块Socket
>
> 客户端 （我们称之为客户端1 ）：
> #!/usr/bin/perl -w
>  use strict;
>  use Socket;
>  use IO::Handle;
>
>  my ($bytes_out, $bytes_in) = (0, 0);
>  my $host = shift || 'localhost';
>  my $port = shift || getservbyname('echo', 'tcp');
>
>  my $protocol = getprotobyname('tcp');
>
>  $host = inet_aton($host);
>  my $data_addr = sockaddr_in($port, $host);
>
>  socket(SOCK, AF_INET, SOCK_STREAM, $protocol) or die "$!\n";
>  # connect the server
>  connect(SOCK, $data_addr) or die "Can't Connect the Server: $!\n";
>
>  SOCK->autoflush(1);
>
>  while ( my $msg_out = <> ) {
>     print SOCK $msg_out;
>     my $msg_in = <SOCK>;
>     print $msg_in;
>
>     $bytes_out += length($msg_out);
>     $bytes_in  += length($msg_in);
>  }
>
>  close SOCK;
>  print "bytes send = $bytes_out, bytes received = $bytes_in\n";
>
>
> 再是服务器端 （ 我们称之为服务端1 ）：
>  #!/usr/bin/perl
>  use strict;
>  use warnings;
>  use Socket;
>  use IO::Handle;
>  use constant MY_ECHO_PORT => 2007;
>
>  my ( $bytes_out, $bytes_in ) = (0, 0);
>
>  my $port = shift || MY_ECHO_PORT;
>  my $protocol = getprotobyname('tcp');
>
>  $SIG{INT} = sub {
>     print STDERR "bytes_send = $bytes_out, bytes_received = $bytes_in\n";
>     exit 0;
>  };
>
>  socket(SOCK, AF_INET, SOCK_STREAM, $protocol) or die "Socket failed: $!";
>  setsockopt(SOCK, SOL_SOCKET, SO_REUSEADDR, 1) or die "$!\n";
>
>  my $my_addr = sockaddr_in($port, INADDR_ANY);
>
>  bind(SOCK, $my_addr);
>  listen(SOCK, SOMAXCONN) or die "Listen() failed:$!\n";
>
>  warn "Waitng for incoming connection on port $port...\n";
>
>  while (1) {
>     next unless my $remote_addr = accept(SESSION, SOCK);
>     my ($port, $hisaddr ) = sockaddr_in($remote_addr);
>
>    warn "Connection from [", inet_ntoa($hisaddr), ", $port]\n";
>
>     SESSION->autoflush(1);
>
>     while ( <SESSION> ) {
>        $bytes_in += length($_);
>        chomp;
>
>        my $msg_out =  (scalar reverse $_). "\n";
>        print SESSION $msg_out;
>        $bytes_out += length($msg_out);
>     }
>
>     warn "Connection from [", inet_ntoa($hisaddr), ", $port]\n";
>     close SESSION;
>  }
>
>  close SOCK;
>
>
> 然后再使用IO::Socket模块重写：
>
> 客户端 （ 我们称之为客户端2）：
> #!/usr/bin/perl
>  use strict;
>  use warnings;
>  use IO::Socket;
>
>  my ($bytes_out, $bytes_in) = (0, 0);
>
>  my $host = shift || 'localhost';
>  my $port = shift || 'echo';
>
>  $SIG{PIPE} = sub {
>     print "it had a PIPE error.\n";
>     exit 0;
>  };
>
>  my $socket = IO::Socket::INET->new("$host:$port") or die "$@\n";
>
>  while ( defined( my $msg_out = STDIN->getline ) ) {
>     print $socket $msg_out;
>     my $msg_in = <$socket>;
>
>     print $msg_in;
>
>     $bytes_out += length $msg_out;
>     $bytes_in  += length $msg_in;
>  }
>
>  $socket->close;
>  print STDERR "bytes send = $bytes_out, bytes_received = $bytes_in\n";
>
> 服务器端（我们称之为：服务端2）：
> #!/usr/bin/perl
>  use strict;
>  use warnings;
>  use IO::Socket qw(:DEFAULT :crlf);
>  use constant MY_ECHO_PORT => 2007;
>
>  $/ = CRLF;
>
>  my ($bytes_out, $bytes_in) = (0, 0);
>
>  my $quit = 0;
>
>  $SIG{INT} = sub { $quit++; };
>
>  my $port = shift || MY_ECHO_PORT;
>
>  my $socket = IO::Socket::INET->new(
>     Listen => 20,
>     LocalPort => $port,
>     Timeout => 60 * 60,
>     Reuse   => 1
>  ) or die "Can't create listen port: $!\n";
>
>  warn "Waiting for incoming connections on port $port ......\n";
>
>  while ( !$quit ) {
>     next unless my $session = $socket->accept;
>
>     $session->autoflush(1);
>
>     my $peer = gethostbyaddr( $session->peeraddr, AF_INET) ||
>
>       $session->peerhost;
>
>     my $port = $session->peerport;
>
>     warn "Connection from [$peer, $port]\n";
>
>     while ( my $str = <$session> ) {
>        print $str, "\n";
>        $bytes_in += length $str;
>        chomp $str;
>        my $msg_out = (scalar reverse $str)."\n";
>        print $msg_out, "\n";
>        print $session $msg_out;
>
>        $bytes_out += length $msg_out;
>     }
>
>     warn "Connection from [$peer, $port] finished\n";
>     close $session;
>  }
>
>  print STDERR "bytes send = $bytes_out, bytes received = $bytes_in\n";
>
>  close $socket;
>
>
> 现在问题就来了。
> 如果我们使用客户端1和客户端2连接服务器端1， 没有问题，很正常。
> 但是如果我使用客户端1和客户端2连接服务器端2是就有问题，
> 发现客户端接受不到任何返回。
>
> 比较奇怪，请帮我看看。
> 谢谢。
>
>
>
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> China-pm mailing list
> China-pm at pm.org
> http://mail.pm.org/mailman/listinfo/china-pm
>



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