wx.pl

# URL of Regional Weather in Hong Kong (updates every 10 minutes)
my $html = get("http://data.weather.gov.hk/wxinfo/ts/text_readings_e.htm");

# Extract temperature from HTML (3 bytes)
$count = () = $html =~ m{Shau Kei Wan[ ]+([\d\.?]+)};
if ($count > 0) {
	$temperature = sprintf("%03d", ($1 * 9/5 + 32) % 1000);
} else {
	$temperature = "...";
}

# Extract humidity (2 bytes)
$count = () = $html =~ m{HK Observatory[ ]+[\S]+[ ]+([\d]+)};
if ($count > 0) {
	$humidity = sprintf("%02d", $1 % 100);
} else {
	$humidity = "..";
}

# Extract wind direction (3 bytes)
my $pattern = "(km/hour)";
my $offset = index($html, $pattern) + length($pattern) + 1;
$html = substr($html, $offset);
$count = () = $html =~ m{Kai Tak[ ]+([^\s]+)};
if ($count > 0) {
	if (lc $1 eq "north")		{ $winddirection = "000"; }
	elsif (lc $1 eq "northeast")	{ $winddirection = "045"; }
	elsif (lc $1 eq "east")		{ $winddirection = "090"; }
	elsif (lc $1 eq "southeast")	{ $winddirection = "135"; }
	elsif (lc $1 eq "south")		{ $winddirection = "180"; }
	elsif (lc $1 eq "southwest")	{ $winddirection = "225"; }
	elsif (lc $1 eq "west")		{ $winddirection = "270"; }
	elsif (lc $1 eq "northwest")	{ $winddirection = "315"; }
	elsif (lc $1 eq "variable")	{ $winddirection = "..."; }
	else {	# When wind direction is either "Calm" or "N/A"
		$winddirection	= "...";
		$windspeed	= "...";
		$windgust	= "...";
	}
} else {
	$winddirection	= "...";
	$windspeed	= "...";
	$windgust	= "...";
}

if ((!defined $windspeed) || (!defined $windgust)){
	# Extract wind speed (3 bytes)
	$count = () = $html =~ m{Kai Tak[ ]+[\S]+[ ]+([\d]+)};
	if ($count > 0) {
		$windspeed = sprintf("%03d", $1 * 0.621371192 % 1000);
	} else {
		$windspeed = "...";
	}
	# Extract wind gust (3 bytes)
	$count = () = $html =~ m{Kai Tak[ ]+[\S]+[ ]+[\S]+[ ]+([\d]+)};
	if ($count > 0) {
		$windgust = sprintf("%03d", $1 * 0.621371192 % 1000);
	} else {
		$windgust = "...";
	}
}

# Extract pressure (5 bytes)
$pattern = "(hPa)";
$offset = index($html, $pattern) + length($pattern) + 1;
$html = substr($html, $offset);
$count = () = $html =~ m{HK Observatory[ ]+([\d\.?]+)};
if ($count > 0) {
	$pressure = sprintf("%05d", $1 * 10 % 100000);
} else {
	$pressure = ".....";
}