另外一个网络的编程问题
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。
