Better Cache Control

[jhunt]

I'm tired of telling people "just clear your browser cache, purge CloudFlare, and THEN it should all render all right.

The site.yml approach was too much (for ?v=[% site.cache.buster %]). Maybe we should do what all the cool kids like @drnic suggest and use webpack or similar semantics.

[jhunt]

I have a solution for this:

diff --git a/lib/Verse.pm b/lib/Verse.pm
index c8ff506..8c54f00 100644
--- a/lib/Verse.pm
+++ b/lib/Verse.pm
@@ -20,6 +20,8 @@ our $BUILD   = "";
 our $ROOT = $ENV{PWD} || '/';
 our $VDIR = -f "$ROOT/site.yml" ? '.' : '.verse';
 
+our %ASSETS;
+
 sub parse_config_string
 {
 	my ($yaml) = @_;
diff --git a/lib/Verse/Template.pm b/lib/Verse/Template.pm
index 21dc7d7..bc5ca97 100644
--- a/lib/Verse/Template.pm
+++ b/lib/Verse/Template.pm
@@ -2,8 +2,11 @@ package Verse::Template;
 use strict;
 use warnings;
 
+use Verse qw();
 use Verse::Utils;
 use Date::Parse qw/strptime/;
+use Digest::SHA1 qw/sha1_hex/;
+use Encode qw/encode_utf8/;
 use POSIX qw/strftime/;
 use base 'Exporter';
 our @EXPORT = qw/
@@ -12,11 +15,11 @@ our @EXPORT = qw/
 
 sub template
 {
-	my ($templates, $vars, $outfile) = @_;
+	my ($templates, $vars, $paths, $outfile) = @_;
 	$templates = [$templates] if ref($templates) ne 'ARRAY';
 
 	for my $template (reverse @$templates) {
-		$vars->{content} = _evaluate(_read($template), $vars, $template);
+		$vars->{content} = _evaluate(_read($template), $vars, $paths, $template);
 		chomp($vars->{content});
 	}
 	return $vars->{content} if !$outfile;
@@ -66,6 +69,7 @@ use constant {
 	T_FILTER  => 31, # filter
 	T_COMMA   => 32, # "," delimiter
 	T_FUNCALL => 33, # <IDENT>(
+	T_ASSET   => 34, # asset
 };
 
 my @NAMES = (
@@ -346,6 +350,7 @@ sub _lex
 		return [T_AND]     if lc($lexeme) eq 'and';
 		return [T_OR]      if lc($lexeme) eq 'or';
 		return [T_FILTER]  if lc($lexeme) eq 'filter';
+		return [T_ASSET]   if lc($lexeme) eq 'asset';
 		return [T_IDENT, $lexeme];
 
 	} elsif ($c =~ m/[0-9]/) {
@@ -607,6 +612,18 @@ sub _filter
 	return $filter;
 }
 
+sub _asset
+{
+	my $asset = ['ASSET'];
+	if (!_at($_[0], T_STRING)) {
+		_unexpected($_[0], 'a quoted asset name, like "styles/main.css"');
+	}
+	push @$asset, _argn($_[0], 0);
+
+	_next($_[0]); _eat($_[0], T_CLOSE, 'a closing "%]"');
+	return $asset;
+}
+
 sub _apply
 {
 	my $fn = ['APPLY'];
@@ -666,6 +683,10 @@ sub _stmt
 		_next($_[0]);
 		$stmt = _filter($_[0]);
 
+	} elsif (_at($_[0], T_ASSET)) {
+		_next($_[0]);
+		$stmt = _asset($_[0]);
+
 	} else {
 		_unexpected($_[0], "a variable name, or a control construct like if, unless, or for");
 	}
@@ -876,6 +897,29 @@ sub _eval
 		return;
 	}
 
+	if ($op eq 'ASSET') {
+		my $divert = $Verse::ASSETS{$args[0]};
+		if (!$divert) {
+			my $root = $vm->{paths}{site};
+			use Data::Dumper; print Dumper($vm->{paths});
+			open my $fh, "<", "$root/$args[0]"
+				or die "Unable to open $root/$args[0]: $!\n";
+			my $sha1 = substr(sha1_hex(encode_utf8(do { local $/; <$fh> })), 0, 12);
+			close $fh;
+
+			my $file = "$args[0]-$sha1";
+			if ($args[0] =~ m{^(.*[^/]+)\.(.*?)$}) {
+				$file = "$1-$sha1.$2";
+			}
+
+			print "[rename] $root/$args[0] -> $root/$file\n";
+			rename "$root/$args[0]", "$root/$file";
+			$divert = $Verse::ASSETS{$args[0]} = $file;
+		}
+		$vm->{out} .= $divert;
+		return;
+	}
+
 	if ($op eq 'APPLY') {
 		# FIXME: precludes nesting fun calls; need ['PRINT', ['APPLY' ...]]
 		my $fn = $args[0]; shift @args;
@@ -930,11 +974,13 @@ sub _eval
 
 sub _evaluate
 {
-	my ($ast, $vars, $file) = @_;
+	my ($ast, $vars, $paths, $file) = @_;
 	my $vm = {
 		current => $file || '{unknown}',
 		out => '',
 		env => [$vars || {}],
+		paths => $paths,
+		assets => {},
 	};
 	_eval($vm, $ast);
 	return $vm->{out};
diff --git a/lib/Verse/Theme.pm b/lib/Verse/Theme.pm
index 32e89e5..81ab672 100644
--- a/lib/Verse/Theme.pm
+++ b/lib/Verse/Theme.pm
@@ -103,7 +103,7 @@ sub render
 		$opt{layout} = path("{theme}/layouts/site.tt") unless -f $opt{layout};
 		unshift @$tpls, $opt{layout};
 	}
-	template($tpls, \%vars, $path);
+	template($tpls, \%vars, verse->{paths}, $path);
 }
 
 sub blog    { Verse::Object::Blog }

[jhunt]

Eseentially, the new [% asset "path/to/asset" %] template thing will transparently checksum-and-rename the asset the first time each such asset is rendered, for a single execution context (a verse process). Future occurrences of the same asset will skip the file operations. All occurrences will result in the replacement of the original asset path with the new path (containing the checksum).