perl Socket实例

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　　Perl socket programming tutorial
　　Socket programming in perl can be done using the low level socket functions or the IO::Socket module.The IO::Socket module provides an object-oriented interface to the socket functions.
　　In this tutorial we are going to use the low level socket functions.
　　实例1：连接百度端口80
　　[root@dou Socket]# cat 1.pl
　　#!/usr/bin/perl -w
　　use strict;
　　# The socket function can be used to create a socket.In the following code example we shall create a tcp socket.
　　use Socket;
　　my $proto = getprotobyname('tcp'); # get the tcp protocol
　　# Create a socket handle(descriptor)
　　socket(SOCKET,AF_INET,SOCK_STREAM,$proto) or die "cant create socket:$!\n";
　　# Connecting to a remote server
　　my $remote = 'www.baidu.com';
　　my $port = 80;
　　my $iaddr= inet_aton($remote) or die "unable to resolve hostname: $remote\n";
　　my $paddr = sockaddr_in($port,$iaddr); # socket address structure
　　connect(SOCKET,$paddr) or die "connect failed : $!\n";
　　print "Connected to $remote on port $port\n";
　　# Close a socket
　　close SOCKET,
　　exit(0);
　　In the above example we connected to baidu.com on port 80.
　　Before the connect function is called the sockaddr_in structure has to be setup.
　　The sockaddr_in structure stores the information about the remote address,
　　address type and port number. The inet_aton function converts a hostname/ip to
　　ip address in long number format.
　　[root@dou Socket]# cat 1.pl
　　#!/usr/bin/perl -w
　　use strict;
　　# The socket function can be used to create a socket.In the following code example we shall create a tcp socket.
　　use Socket;
　　use Encode;
　　my $proto = getprotobyname('tcp'); # get the tcp protocol
　　# Create a socket handle(descriptor)
　　socket(SOCKET,AF_INET,SOCK_STREAM,$proto) or die "cant create socket:$!\n";
　　# Connecting to a remote server
　　my $remote = 'www.baidu.com';
　　my $port = 80;
　　my $iaddr= inet_aton($remote) or die "unable to resolve hostname: $remote\n";
　　my $paddr = sockaddr_in($port,$iaddr); # socket address structure
　　connect(SOCKET,$paddr) or die "connect failed : $!\n";
　　print "Connected to $remote on port $port\n";
　　# Send data
　　# Once connected it's time to start communication by sending some data.The send function can be used for this.
　　# Send some data to remote server - the HTTP GET command
　　send(SOCKET,"GET / HTTP/1.0\n\n",0) or die "send failed:$!\n";
　　# Receive reply from server - perl way of reading from stream.
　　# Can also do recv(SOCKET,$msg,2000,0).
　　while(my $line = ) {
　　#       $line = encode_utf8($line);
　　$line = encode("utf-8",decode("gbk",$line));#（translate gbk code to utf-8 code）
　　print "$line\n";
　　}
　　# Close a socket
　　close SOCKET,
　　exit(0);
　　Revise
　　In the above examples we learned the following socket operations.
　　1. Create a socket
　　2. Connect to remote server/system.
　　3. Send data
　　4. Receive a reply
　　The socket program we wrote above is called a client.
　　A client connects to a remote server for exchange of information/data.
　　Apart from the client the other type of socket program we are going to write is called a server.
　　The server serves data to clients connecting to it.
　　So lets move on to the next section to do some server programming in perl.
　　Server
　　The basic steps for making a server are :
　　1. Create a socket
　　2. Bind to a local address and local port
　　3. Listen for incoming connections
　　4. Accept incoming connections
　　5. Communicate the with the newly connected client - send and receive data.
　　So a server does not connect out to a system, instead it waits for incoming connections.
　　We have already seen how to create a socket.
　　So the next task to make a server would be to bind the socket.
　　The bind function can be used for this task.
　　Lets take a quick example
　　[root@dou Socket]# cat server.pl
　　#!/usr/bin/perl -w
　　use strict;
　　use Socket;
　　$| = 1;
　　#create a socket handle(descriptor)
　　socket(SERVER,AF_INET,SOCK_STREAM,(getprotobyname('tcp'))[2]) or die "cant create socket :$!\n";
　　#bind to local port 10000
　　my $port = 10000;
　　#the socket is bound to port 10000 and address "any".After bind the socket has to be put in listen mode.
　　bind(SERVER,sockaddr_in($port,INADDR_ANY)) or die "bind failed:$!\n";
　　# listening the incoming connections
　　listen(SERVER,10);
　　print "Server is now listening...\n";
　　# After calling listen,the socket is ready to accept incoming connections using the accept function.
　　This shall be done in a loop so that the program can accept connections again and again.
　　#accept incoming connections and talt to clients
　　while(1) {
　　my $addrinfo = accept(TALK,SERVER);
　　my($port,$iaddr) = sockaddr_in($addrinfo);
　　my $clienthost = gethostbyaddr($iaddr,AF_INET);
　　print "Connection accepted from $clienthost:$port\n";
　　# send some message to the client
　　print TALK "hello client how are you\n";
　　close TALK;
　　}
　　#close the socket
　　close SERVER;
　　exit(0);
　　[root@dou socket]# telnet localhost 10000
　　Trying 127.0.0.1...
　　Connected to localhost.localdomain (127.0.0.1).
　　Escape character is '^]'.
　　hello client how are you
　　Connection closed by foreign host.
　　指定server的ip地址：
　　[root@dou Socket]# cat 2.pl
　　#!/usr/bin/perl -w
　　use strict;
　　use Socket;
　　$| = 1;
　　#create a socket handle(descriptor)
　　socket(SERVER,AF_INET,SOCK_STREAM,(getprotobyname('tcp'))[2]) or die "cant create socket :$!\n";
　　#bind to local port 10000
　　my $port = 10000;
　　my $server = "192.168.0.6";
　　my $iaddr = inet_aton($server);
　　my $paddr = sockaddr_in($port,$iaddr);
　　#the socket is bound to port 10000 and address "any".After bind the socket has to be put in listen mode.
　　bind(SERVER,$paddr) or die "bind failed:$!\n";
　　# listening the incoming connections
　　listen(SERVER,10);
　　print "Server is now listening...\n";
　　# After calling listen,the socket is ready to accept incoming connections using the accept function. This shall be done in a loop so that the program can accept connections again and again.
　　#accept incoming connections and talt to clients
　　while(1) {
　　my $addrinfo = accept(TALK,SERVER);
　　my($port,$iaddr) = sockaddr_in($addrinfo);
　　my $clienthost = gethostbyaddr($iaddr,AF_INET);
　　print "Connection accepted from $clienthost:$port\n";
　　# send some message to the client
　　print TALK "hello client how are you\n";
　　close TALK;
　　}
　　#close the socket
　　close SERVER;
　　exit(0);
　　高级技术：
　　Asynchronouse I/O
　　Multiple clients can be handled by asynchronous event driven I/O. IO::Select can be used for this.
　　[root@dou Socket]# cat iosocket.pl
　　#!/usr/bin/perl -w
　　use strict;
　　use Socket;
　　use IO::Select;
　　$| = 1;
　　my $socket;
　　my $servtoclient;
　　#create a socket handle(descriptor)
　　my $proto = getprotobyname('tcp');
　　socket($socket,PF_INET,SOCK_STREAM,$proto) or die "create socket failed:$!\n";
　　#bind to local port
　　my $port = 10001;
　　my $server = "192.168.0.6";
　　my $iaddr = inet_aton($server);
　　my $paddr = sockaddr_in($port,$iaddr);
　　bind($socket,$paddr) or die "bind failed:$!\n";
　　#listen incoming connections
　　listen($socket,10);
　　print "Server $server on port $port is now listening ...\n";
　　#accept incoming connections and talk to clients
　　my $select = IO::Select->new();
　　$select->add($socket);
　　while(1) {
　　my @ready = $select->can_read(0);
　　foreach my $select_io(@ready) {
　　#new connection read
　　if($select_io == $socket) {
　　my $clientinfo = accept($servtoclient,$socket);
　　my($clientport,$clientiaddr) = sockaddr_in($clientinfo);
　　my $clienthost = gethostbyaddr($clientiaddr,AF_INET);
　　print "Connection accepted from $clienthost : $clientport\n";
　　# send some message to the client
　　send($servtoclient,"Hello client[$clienthost]! Nice to meet you !\n",0);
　　$select->add($servtoclient);
　　}
　　# existing client read
　　else {
　　chop(my $clientinput = );
　　chop($clientinput);
　　if ($clientinput =~ /quit/i) {
　　$select->remove($select_io);
　　$select_io->close;
　　}else {
　　print "Received -- $clientinput\n";
　　# send reply back to client
　　send($select_io,"OK : $clientinput\n",0);
　　}
　　}
　　}
　　}
　　#close the socket
　　close $socket;
　　exit(0);
　　server端运行命令
　　[root@dou Socket]# perl iosocket.pl &
　　[1] 3580
　　[root@dou Socket]# Server 192.168.0.6 on port 10001 is now listening ...
　　[root@dou Socket]#
　　客户端访问：下面是服务器返回的信息
　　[root@dou ~]# telnet 192.168.0.6 10001
　　Trying 192.168.0.6...
　　Connected to dou.perl.gov (192.168.0.6).
　　Escape character is '^]'.
　　Hello client[dou.perl.gov]! Nice to meet you !
　　同时server端也返回信息：
　　[root@dou Socket]# Connection accepted from dou.perl.gov : 42617
　　客户端开始发送信息：
　　ls---->send
　　OK : ls ---->receive
　　hello---->send
　　OK : hello ---->receive
　　hello world---->send
　　OK : hello world ---->receive
　　同时server端也返回信息：
　　Received -- ls
　　Received -- hello
　　Received -- hello world
　　下面是更经典的iosocket程序：
　　#!/usr/bin/perl -w
　　use strict;
　　use Socket;
　　use IO::Select;
　　$| = 1;
　　my $path = "/usr/kerberos/sbin:/usr/kerberos/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin";
　　my @paths = split(/:/,$path);
　　my $hit = 0;
　　my $command;
　　my @lines;
　　my $line;
　　my $socket;
　　my $servtoclient;
　　my $reply;
　　#create a socket handle(descriptor)
　　my $proto = getprotobyname('tcp');
　　socket($socket,PF_INET,SOCK_STREAM,$proto) or die "create socket failed:$!\n";
　　#bind to local port
　　my $port = 10001;
　　my $server = "192.168.0.6";
　　my $iaddr = inet_aton($server);
　　my $paddr = sockaddr_in($port,$iaddr);
　　bind($socket,$paddr) or die "bind failed:$!\n";
　　#listen incoming connections
　　listen($socket,10);
　　print "Server $server on port $port is now listening ...\n";
　　#accept incoming connections and talk to clients
　　my $select = IO::Select->new();
　　$select->add($socket);
　　while(1) {
　　my @ready = $select->can_read(0);
　　foreach my $select_io(@ready) {
　　if($select_io == $socket) {
　　my $clientinfo = accept($servtoclient,$socket);
　　my($clientport,$clientiaddr) = sockaddr_in($clientinfo);
　　my $clienthost = gethostbyaddr($clientiaddr,AF_INET);
　　print "Connection accepted from $clienthost : $clientport\n";
　　send($servtoclient,"Hello client[$clienthost]! Nice to meet you !\n",0);
　　$select->add($servtoclient);}
　　else {
　　while(chop(my $clientinput = )) {
　　chop($clientinput);
　　$clientinput =~ s/^[ \t]*//;
　　if ($clientinput =~ /quit/i) {
　　$select->remove($select_io);
　　$select_io->close;
　　last;   # (跳出while循环jump out the loop of while)
　　#close $socket;
　　#exit 0;
　　}else {
　　@lines = split(/[ ]/,$clientinput);
　　chomp($command = $lines[0]);
　　foreach my $dir (@paths) {
　　search($dir);
　　if ($hit == 1) {
　　last; # （跳出foreach循环jump out the loop of foreach）
　　}
　　}
　　if ($hit != 0) {
　　send($select_io, "Command is [$command]:\n",0);
　　$reply = `$clientinput`;
　　#send reply back to client
　　send($select_io,"$reply",0);
　　} else {
　　send($select_io,"you enter string [$clientinput]\n",0);
　　}
　　}
　　}
　　}
　　}
　　}
　　#close the socket
　　close $socket;
　　exit(0);
　　sub search {
　　my $dir = shift;
　　opendir(DIR,"$dir") or die "cant open dir:$dir:$!\n";
　　my @files = readdir(DIR);
　　closedir(DIR);
　　foreach my $file (@files) {
　　next if ($file =~ m/^\.$/ || $file =~ m/^\.\.$/);
　　if ("$file" eq "$command") {
　　$hit += 1;
　　return(0);
　　}  else {
　　$hit = 0;
　　}
　　}
　　}
　　服务器端：
　　[root@dou Socket]# perl 7.pl &
　　[1] 3641
　　[root@dou Socket]# Server 192.168.0.6 on port 10001 is now listening ...
　　[root@dou Socket]# Connection accepted from dou.perl.gov : 33965
　　客户端：
　　[root@dou ~]# telnet 192.168.0.6 10001
　　Trying 192.168.0.6...
　　Connected to dou.perl.gov (192.168.0.6).
　　Escape character is '^]'.
　　Hello client[dou.perl.gov]! Nice to meet you !
　　ls
　　Command is [ls]:
　　1.pl
　　1.py
　　2.pl
　　44.pl
　　4.pl
　　5.pl
　　6.pl
　　7.pl
　　aaa
　　client.pl
　　ht.pl
　　iosocket.pl
　　iosocket.pl.orig
　　open_client.pl
　　server.pl
　　tk.pl
　　hostname
　　Command is [hostname]:
　　dou.perl.gov
　　hostname
　　Command is [hostname]:
　　dou.perl.gov
　　quit
　　Connection closed by foreign host.
　　上述程序的说明：
　　1）服务器端perl 7.pl &将程序至于后台运行
　　2）客户端使用telnet进行测试
　　3）可以输入linux中常用的命令：比如：ls hostname ifconfig eth0等。并且命令的前面可以有多个空格或者tap键。
　　4）该程序通过搜索系统$PATH路径来确定输入的string是否是一个命令，如果是系统命令的话将$hit的值加1，程序
　　通过控制$hit的值来觉得是否输出命令的结果，还是单纯的字符串。