Source of common.inc.plp

<:
use 5.014;
use utf8;
use warnings;
no  warnings 'qw';  # you know what you doing
no  warnings 'uninitialized';  # save some useless checks for more legible code
use open ':std' => ':utf8';

use File::stat 'stat';
use HTTP::Date;
use Encode qw( decode_utf8 );

sub Alert {
	my ($html, $debug) = @_;
	ref $html eq 'ARRAY' or $html = [$html];
	my ($title, @lines) = @{$html};
	$body = "<h2>$title</h2>";
	$body .= "\n<p>$_</p>" for @lines;
	$body .= "\n<pre>$debug</pre>" if $Dev and $debug;
	say "<div class=error>$body</div>\n";
}

BEGIN {
	require Time::HiRes;
	our $Time = [Time::HiRes::gettimeofday()];

	$PLP::ERROR = sub {
		my ($text, $html) = @_;
		warn $text;
		unless ($PLP::sentheaders and $PLP::sentheaders->[0] !~ m{/PLP\.pm\z}) {
			Html({nocache => 1});
			say '<h1>Page unavailable</h1>';
		}
		Alert("<strong>Fatal error</strong>: $html.");
	};

	# user request
	our $Dev = $ENV{HTTP_HOST} =~ /\bdev\./;
	our ($file) = $ENV{SCRIPT_FILENAME} =~ m{ ([^/]+) \.plp$ }x;
}

our $Request = decode_utf8($ENV{PATH_INFO} =~ s{^/}{}r);

our $style;
our $showkeys = !exists $get{keys} ? undef :
	($get{keys} ne '0' && ($get{keys} || 'always'));

$header{content_type} = 'text/html; charset=utf-8';

sub stylesheet {
	my ($avail) = @_;
	my @avail = ref $avail eq 'ARRAY' ? @{$avail} : $avail or return;
	my %styles = map {$_ => $_} @avail;

	if (defined( my $setstyle = $get{style} )) {
		$style = $styles{ $setstyle };
		eval {
			require CGI::Cookie;
			my $cookie = CGI::Cookie->new(
				-name    => 'style',
				-value   => $setstyle || '',
				-path    => '/',  # site-wide; current page is confusing to most users
				-expires => $setstyle ? '+5y' : '-1d',
			) or die "empty object returned\n";
			AddCookie($cookie->as_string);
		} or warn "Unable to create style cookie: $@";
	}

	$style ||= exists $cookie{style} && $styles{ $cookie{style} } || $avail[0];

	return map { sprintf(
		'<link rel="%s" type="text/css" media="all" href="%s" title="%s">',
		$_ eq $style ? 'stylesheet' : 'alternate stylesheet', "/$_.css?1.10", $_
	) } @avail;
}

sub checkmodified {
	my $lastmod = 0;
	for (@_) {
		my $mod = stat $_ or next;
		$mod = $mod->mtime or next;
		$lastmod = $mod if $mod gt $lastmod;
	}

	for ($ENV{HTTP_IF_MODIFIED_SINCE} || ()) {
		next if str2time($_) < $lastmod;
		$header{status} = '304 Same old';
		exit;
	}

	$header{'Last-Modified'} = time2str($lastmod);
}

sub Html {
	my ($meta) = @_;

	unless ($meta->{nocache}) {
		# announce and check data modification
		checkmodified(
			$ENV{SCRIPT_FILENAME},
			(grep { /\bShiar_/ } values %INC),
			$meta->{data} ? @{ $meta->{data} } : (),
		);
		$header{'Cache-Control'} = 'max-age='.(24*60*60);
	}

	# default fallbacks
	$meta->{stylesheet} ||= [qw'light dark circus mono red terse'];
	$meta->{charset} ||= 'utf-8';

	# convert options to arrays
	ref $_ eq 'ARRAY' or $_ = [$_]
		for grep {$_} $meta->{raw}, $meta->{description}, $meta->{keywords};

	# document headers before output
	$header{content_type} = "text/html; charset=$meta->{charset}"
		unless $PLP::sentheaders;
	unshift @{ $meta->{raw} }, stylesheet($meta->{stylesheet});

	# optional amends
	push @{ $meta->{raw} }, (
		'<!--[if lte IE 6]><style> .help dl.legend dt {margin:0 0 1px} </style><![endif]-->',
		'<!--[if lte IE 7]><style> .help dl.legend dd {float:none} </style><![endif]-->',
		!$showkeys ? '<style type="text/css"> .no {visibility:hidden} </style>'
			: $showkeys eq 'ghost' ? '<style type="text/css"> .no, .alias {opacity:.5} </style>'
			: (),
		'<script type="text/javascript" src="/keys.js?1.6"></script>',
	) if $meta->{keys};

	# leading output
	say '<!DOCTYPE html>';
	say '<html lang="en">';
	say '';
	say '<head>';
	say sprintf '<meta http-equiv="content-type" content="%s">', $header{content_type};
	say sprintf '<title>%s</title>', $meta->{title};
	say sprintf '<meta name="description" content="%s">', EscapeHTML($_)
		for join(' ', @{ $meta->{description} }) || ();
	say sprintf '<meta name="keywords" content="%s">', EscapeHTML($_)
		for join(', ', @{ $meta->{keywords} }) || ();
	say '<meta name="viewport" content="width=device-width, initial-scale=1">';
	say '<link rel="icon" type="image/png" href="/clip.png">';
	say for map { @{$_} } $meta->{raw} || ();
	say '<meta name="robots" content="noindex">' if $Dev;
	say '</head>';
	say '';
	say sprintf '<body id="%s">', $file;

	# development version indicator
	printf '<p style="%s">beta</p>', join('; ',
		'position: fixed',
		'right: 1em',
		'opacity: .5',
		'border: 1ex solid red',
		'border-width: 1ex 0',
		'z-index: 1',
		'background: inherit',
	) if $Dev;

	# prepare trailing output
	PLP_END {
		print <<"EOT";
<p class="footer">
	<a href="/" rel="start">sheet.shiar.nl</a>/$file.<a href="/source/$file.plp"
	 rel="source" title="Written in Perl">plp</a>
	version <a href="http://git.shiar.nl/sheet.git/history/HEAD:/$file.plp"
	 rel="vcs-git" title="Git repository">$meta->{version}</a>
	created by <a href="http://shiar.nl/" rel="author">Shiar</a> •
	<a href="http://www.fsf.org/licensing/licenses/agpl-3.0.html" rel="license copyright"
	 title="Licensed under the GNU Affero General Public License, version 3">AGPLv3</a>
EOT
		say sprintf '• %.3fs', Time::HiRes::tv_interval($Time) if $Dev and $Time;
		say '</p>';
		say '';
		say '</html>';
	};
}

sub showlink {
	my ($title, $href, $selected) = @_;
	return sprintf(
		$selected ? '<strong>%s</strong>' : '<a href="%2$s">%s</a>',
		EscapeHTML($title), EscapeHTML($href)
	);
}