From 0bf15a019e9201754f43b7a874b8cc02c96d2130 Mon Sep 17 00:00:00 2001
From: Mischa POSLAWSKY <perl@shiar.org>
Date: Fri, 10 Dec 2010 01:37:19 +0100
Subject: [PATCH] browser: automatic retrieval of caniuse data

Take care to negotiate If-Modified-Since to minimise downloads.
---
 tools/convert-caniuse.pl | 39 +++++++++++++++++++++++++++++++++++++--
 1 file changed, 37 insertions(+), 2 deletions(-)

diff --git a/tools/convert-caniuse.pl b/tools/convert-caniuse.pl
index f013baf..5f619b1 100755
--- a/tools/convert-caniuse.pl
+++ b/tools/convert-caniuse.pl
@@ -4,9 +4,42 @@ use strict;
 use warnings;
 
 use Data::Dump 'pp';
-use File::Slurp 'read_file';
 use JSON;
 
+if (@ARGV) {
+	require Time::Piece;
+	require LWP::UserAgent;
+	require File::stat;
+
+	my $target = 'browser-support.inc.pl';
+	my $source = 'http://caniuse.com/data.json';
+
+	my $ua = LWP::UserAgent->new;
+	$ua->agent('sheet.shiar.nl/browser');
+	$ua->default_header('If-Modified-Since' => scalar gmtime $_->mtime)
+		for File::stat::stat($target);
+
+	my $res = $ua->get($source) or die "No data from $source\n";
+	!$res->is_error or die $res->status_line;
+	say $res->status_line;
+
+	exit 0 if $res->code == 304;  # unmodified
+
+	my $data = decode_json($res->decoded_content) or die "Parse error: $!";
+	my $updated = eval {
+		s/ GMT$//,
+		return Time::Piece->strptime($_)->ymd for $res->header('Last-Modified')
+	} || time;
+
+	open my $save, '>', (my $download = "browser-support-$updated.inc.pl");
+	print {$save} pp($data);
+	close $save;
+
+	symlink $download, "$target.new" and rename "$target.new", $target
+		or die "New data at $download not linked: $!";
+	exit 0;
+}
+
 local $/;  # slurp
 my $source = readline;
 
@@ -45,6 +78,8 @@ convert-caniuse - Turn Javascript data into an equivalent Perl structure
 
 =head1 SYNOPSIS
 
-	curl http://caniuse.com/jsonp.php |
+	curl http://caniuse.com/data.json |
 	tools/convert-caniuse.pl > browser-support.inc.pl
 
+	tools/convert-caniuse.pl auto
+
-- 
2.30.0