P005 SLUŽBY POČÍTAČOVÝCH SÍTÍ

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Cgi-bin

Jednoduché cgi-bin:

#!/usr/bin/perl -w
print "Content type: text/plain\n\n";
print "Simple script.\n";

Práva pro provádění:

chmod +x ab.cgi

HTML výstup (text/html):

#!/usr/bin/perl -w
print "Content type: text/html\n\n";
print <<EOF;
<HTML><HEAD><TITLE>
Script ab.cgi
</TITLE></HEAD>
<BODY>
This is HTML body generated by script
</BODY></HTML>
EOF

Počítadlo:

#!/usr/bin/perl
$LOCK_EX = 2;
$LOCK_UN = 8;
$counter_file =
	"/home/user/public_html/counter_file";
print "Content-type: text/plain", "\n\n";
open (FILE, "+< $counter_file") ||
	die "Error opening counter file.\n";
flock (FILE, $LOCK_EX);
$count = <FILE>;
seek (FILE, 0, SEEK_SET);
print FILE ++$count;
close (FILE);
print "You are visitor number $count\n";

Package, moduly, reference, objekty

package, $Sport::swim, @::fields.

@EXPORT, @EXPORT_OK, @ISA.

use Curses;
use Curses qw(initscr endwin);

Reference:

$i = 10;
$j = $i;
print "$$j\n";
$$j += 16;
print "$$j\n";

10
26

SCALAR(0x1001af8c)

Adresa funkcí:

sub func1 {
	print "Func1 called\n";
	}
sub func2 {
	print "Func2 called\n";
	}
$ref = \&func1;
&$ref();
$ref = \&func2;
&$ref();

Func1 called
Func2 called

Anonymní funkce:

sub func1 {
	print "Func1 called\n";
	}
$ref = \&func1;
&$ref();
$ref = sub { print "Anonymous function\n"; };
&$ref();

Konstruktor třídy:

package Widget;
sub new
	{
	my $arg = shift;
	my $class = (ref $arg) || $arg;
	my $self = { };
	bless $self, $class;
	$self->init( @_ );
	$self;
	}

Volání:

my $w = new Widget();
$w->resize(20, 5);

Volání odkazem na objekt:

$w = Widget->new();
$x = $w->new();

-w

use strict;

no strict qw(...);

-w

Moduly CGI, CGI_Lite a CGI::*

Základní volání:

$q = new CGI;
$name = $q->param('name');

$q->header;
$q->header('image/jpeg');

Formulář:

#!/usr/bin/perl -w

use CGI;
$q = new CGI;

print $q->header, $q->start_html("Form");
print $q->startform, "Your name", "<BR>",
		$q->textfield('name'), "<P>";
print $q->radio_group('-name' => 'siblings',
    '-values' => ['none', "brother", "sister",
			    "more of any" ],
    '-default' => "none");
print $q->submit('Action', 'Yes');
print " Variables: 
", $q->dump;
print $q->endform;
print $q->end_html;

LWP

Stažení a tisk dokumentu:

use LWP::Simple;
print get "http://www/";

Převod na text:

use LWP::Simple;
use HTML::Parse;
print parse_html(get "http://www/")->format;

Jak stáhnout perl:

$ perl -MLWP::Simple -e '
getstore "ftp://sunsite.mff.cuni.cz/Languages/
		 Perl/CPAN/src/latest.tar.gz",
	"perl.tar.gz"; '

Modul LWP::UserAgent

use LWP::UserAgent;
$client = new LWP::UserAgent();
$client->agent("Microsoft Exploder 0.99");
$request = new HTTP::Request('GET',
		    'http://www.fi.muni.cz/');
$request->header("Accept" => "text/html");
$answer = $client->request($request);
print $answer->content
		    if $answer->is_success();

Další moduly:

MIME::Base64, MIME::Quotedprint, HTTP::*, HTML::*.

perl/Tk

http://w4.lns.cornell.edu/~pvhp/ptk/ptkTOC.html
			 /~pvhp/ptk/doc/

Widgety (přípravky):

Hello world:

#!/usr/bin/perl -w
use strict;
use Tk;
my $main = new MainWindow;
$main->Label(-text => "Hello, world")->pack();
$main->Button(-text => "End",
		-command => \&exit)->pack();
MainLoop;

$main->Button(-text => "End", -command =>
	sub {print "Button pressed\n"; exit }
				)->pack();

Následující: JavaScript
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Jan Pazdziora adelton@informatics.muni.cz