Compare Kobo store prices

kobocompare

#!/usr/bin/perl -w
# Compare book prices across multiple Kobo stores
#
use strict;
use warnings;
use threads;
use WWW::Mechanize;

# FIXME
my $mech = WWW::Mechanize->new(
	ssl_opts => { verify_hostname => 0 }
);

my %stores = (
	"Austria" => "https://www.kobo.com/at/de/ebook/",
	"Australia" => "https://www.kobo.com/au/en/ebook/",
	"Belgium (French)" => "https://www.kobo.com/be/fr/ebook/",
	"Belgium (Dutch)" => "https://www.kobo.com/be/nl/ebook/",
	"Brazil" => "https://www.kobo.com/br/pt/ebook/",
	"Canada (English)" => "https://www.kobo.com/ca/en/ebook/",
	"Canada (French)" => "https://www.kobo.com/ca/fr/ebook/",
	"Switzerland (French)" => "https://www.kobo.com/ch/fr/ebook/",
	"Germany" => "https://www.kobo.com/de/de/ebook/",
	"Denmark" => "https://www.kobo.com/dk/da/ebook/",
	"Spain" => "https://www.kobo.com/es/es/ebook/",
	"Finland" => "https://www.kobo.com/fi/fi/ebook/",
	"France" => "https://www.kobo.com/fr/fr/ebook/",
	"UK" => "https://www.kobo.com/gb/en/ebook/",
	"Greece" => "https://www.kobo.com/gr/en/ebook/",
	"Hong Kong (English)" => "https://www.kobo.com/hk/en/ebook/",
	"Hong Kong (Chinese)" => "https://www.kobo.com/hk/zh/ebook/",
	"Eire" => "https://www.kobo.com/ie/en/ebook/",
	"India" => "https://www.kobo.com/in/en/ebook/",
	"Italy" => "https://www.kobo.com/it/it/ebook/",
	"Japan" => "https://www.kobo.com/jp/ja/ebook/",
	"Luxembourg" => "https://www.kobo.com/lu/fr/ebook/",
	"Mexico" => "https://www.kobo.com/mx/es/ebook/",
	"Malaysia" => "https://www.kobo.com/my/en/ebook/",
	"Holland" => "https://www.kobo.com/nl/nl/ebook/",
	"Norway" => "https://www.kobo.com/no/nb/ebook/",
 	"New Zealand" => "https://www.kobo.com/nz/en/ebook/",
	"Poland" => "https://www.kobo.com/pl/pl/ebook/",
	"Portugal" => "https://www.kobo.com/pt/pt/ebook/",
	"Sweden" => "https://www.kobo.com/se/sv/ebook/",
	"Singapore" => "https://www.kobo.com/sg/en/ebook/",
	"Turkey" => "https://www.kobo.com/tr/tr/ebook/",
	"Taiwan" => "https://www.kobo.com/tw/zh/ebook/",
	"USA" => "https://www.kobo.com/us/en/ebook/",
	"World-wide" => "https://www.kobo.com/ww/en/ebook/",
	"South Africa" => "https://www.kobo.com/za/en/ebook/",
	"Philippines" => "https://www.kobo.com/ph/en/ebook/",
	"Thailand" => "https://www.kobo.com/th/en/ebook/",
	"Cyprus" => "https://www.kobo.com/cy/en/ebook/",
	"Czech Republic" => "https://www.kobo.com/cz/cs/ebook/",
	"Estonia" => "https://www.kobo.com/ee/en/ebook/",
	"Lithuania" => "https://www.kobo.com/lt/en/ebook/",
	"Malta" => "https://www.kobo.com/mt/en/ebook/",
	"Romania" => "https://www.kobo.com/ro/ro/ebook/",
	"Slovak Republic" => "https://www.kobo.com/sk/en/ebook/",
	"Slovenia" => "https://www.kobo.com/si/en/ebook/",
);

# Currency rates as of late-ish 2023. Should fetch these automatically...
my %rates = (
	"GBP" => 1.0,
	"USD" => 0.79402,
	"CAD" => 0.583979993380163,
	"EUR" => 0.859160264040688,
	"AUD" => 0.50942512511228,
	"INR" => 0.009615580263062,
	"BRL" => 0.163208031369973,
	"DKK" => 0.115310137956743,
	"HKD" => 0.101322338276436,
	"JPY" => 0.00542642431523,
	"MXN" => 0.047523831555867,
	"NOK" => 0.074087672866888,
	"PLN" => 0.192100811907984,
	"SEK" => 0.072038674834173,
	"CHF" => 0.899686520376176,
	"TWD" => 0.024918649487445, # New Taiwan Dollar
	"TRY" => 0.029931861113694,
	"CZK" => 0.035607803812372,
	"NZD" => 0.469622719489874,
	"RON" => 0.174101094205896,
	"ZAR" => 0.042517865896064,
	"PHP" => 0.01402610689716,
	"MYR" => 0.168817987152034,
	"SGD" => 0.586037401138296,
);

my $book = shift;

# Allow parameter to be a complete URL - we just want the trailing part of the path
$book =~ s{.*/}{};

# Thread method to fetch the price and currency for a country at a URL
sub get_price {
	my $country = shift;
	my $url = shift;
	$mech->get($url);
	my $content = $mech->content;

	my $price;
	if ($content =~ m{<meta.*?property="og:price".*?content="(.*?)".*?>}m) {
		$price = $1;
		$price =~ s/,/./;
	}
	my $currency;
	if ($content =~ m{<meta.*?property="og:currency_code".*?content="(.*?)".*?>}m) {
		$currency = $1;
	}
	return ($country, $price, $currency);
}

my @threads;

# Run one thread to check each store. This is simple but a bit excessive
foreach my $country (sort keys %stores) {
	push @threads, threads->create(\&get_price, $country, $stores{$country} . $book);
}

my $cheapestPrice = undef;
my @cheapestStore;
my $longestCountry = 0;

my @results;

foreach my $thread (@threads) {
	my ($country, $price, $currency) = $thread->join();

	$longestCountry = length($country) if length($country) > $longestCountry;

	if (defined $price && defined $currency) {
		if (exists $rates{$currency}) {
			my $gbp = $rates{$currency} * $price;
			push @results, [ $country, $currency, $price, $gbp ];
			if ((defined $cheapestPrice && $gbp < $cheapestPrice)
				|| !defined $cheapestPrice) {
				$cheapestPrice = $gbp;
				@cheapestStore = ();
			}
			if ($gbp <= $cheapestPrice) {
				push @cheapestStore, $country;
			}
		} else {
			print STDERR "Unknown rate for $currency ($country)\n";
		}
	}
}

foreach my $aref (sort {$a->[3] <=> $b->[3]} @results) {
	printf("%-*s £%.2f %3s %s\n", $longestCountry, $aref->[0], $aref->[3], $aref->[1], $aref->[2]);
}

printf("\nCheapest price is £%.2f in:\n", $cheapestPrice);
foreach my $c (@cheapestStore) {
	printf("\t%s %s\n", $c, $stores{$c} . $book);
}

Now fetches the store results in multiple threads, so is much much faster.

The output formatting is slightly cleaner and includes the store URLs at the end for convenience.