From f026dbdd392c9dd5fddbdad9a2240738d4956640 Mon Sep 17 00:00:00 2001
From: Eric Wong <e@80x24.org>
Date: Sun, 20 Jan 2019 04:21:07 +0000
Subject: www: admin-configurable CSS via "publicinbox.css"

Maybe we'll default to a dark theme to promote energy savings...

See contrib/css/README for details
---
 lib/PublicInbox/Config.pm    |   3 ++
 lib/PublicInbox/Hval.pm      |  14 -----
 lib/PublicInbox/WWW.pm       | 123 +++++++++++++++++++++++++++++++++++++++++++
 lib/PublicInbox/WwwStream.pm |   2 +-
 4 files changed, 127 insertions(+), 15 deletions(-)

(limited to 'lib')

diff --git a/lib/PublicInbox/Config.pm b/lib/PublicInbox/Config.pm
index 355e64bf..cead7fc2 100644
--- a/lib/PublicInbox/Config.pm
+++ b/lib/PublicInbox/Config.pm
@@ -49,6 +49,9 @@ sub new {
 		my $nod = join('|', @domains);
 		$self->{-no_obfuscate_re} = qr/(?:$nod)\z/i;
 	}
+	if (my $css = delete $self->{'publicinbox.css'}) {
+		$self->{css} = _array($css);
+	}
 
 	$self;
 }
diff --git a/lib/PublicInbox/Hval.pm b/lib/PublicInbox/Hval.pm
index a120a291..0315d759 100644
--- a/lib/PublicInbox/Hval.pm
+++ b/lib/PublicInbox/Hval.pm
@@ -11,20 +11,6 @@ use PublicInbox::MID qw/mid_clean mid_escape/;
 use base qw/Exporter/;
 our @EXPORT_OK = qw/ascii_html obfuscate_addrs to_filename/;
 
-# User-generated content (UGC) may have excessively long lines
-# and screw up rendering on some browsers, so we use pre-wrap.
-#
-# We also force everything to the same scaled font-size because GUI
-# browsers (tested both Firefox and surf (webkit)) uses a larger font
-# for the Search <form> element than the rest of the page.  Font size
-# uniformity is important to people who rely on gigantic fonts.
-# Finally, we use monospace to ensure the Search field and button
-# has the same size and spacing as everything else which is
-# <pre>-formatted anyways.
-use constant STYLE =>
-	'<style>pre{white-space:pre-wrap}' .
-	'*{font-size:100%;font-family:monospace}</style>';
-
 my $enc_ascii = find_encoding('us-ascii');
 
 sub new {
diff --git a/lib/PublicInbox/WWW.pm b/lib/PublicInbox/WWW.pm
index a0fd7fa7..863da85a 100644
--- a/lib/PublicInbox/WWW.pm
+++ b/lib/PublicInbox/WWW.pm
@@ -6,6 +6,7 @@
 # We focus on the lowest common denominators here:
 # - targeted at text-only console browsers (w3m, links, etc..)
 # - Only basic HTML, CSS only for line-wrapping <pre> text content for GUIs
+#   and diff/syntax-highlighting (optional)
 # - No JavaScript, graphics or icons allowed.
 # - Must not rely on static content
 # - UTF-8 is only for user-content, 7-bit US-ASCII for us
@@ -118,6 +119,8 @@ sub call {
 		r301($ctx, $1, $2);
 	} elsif ($path_info =~ m!$INBOX_RE/_/text(?:/(.*))?\z!o) {
 		get_text($ctx, $1, $2);
+	} elsif ($path_info =~ m!$INBOX_RE/([\w\-\.]+)\.css\z!o) {
+		get_css($self, $2);
 	} elsif ($path_info =~ m!$INBOX_RE/($OID_RE)/s/\z!o) {
 		get_vcs_object($ctx, $1, $2);
 	} elsif ($path_info =~ m!$INBOX_RE/($OID_RE)/s/([\w\.\-]+)\z!o) {
@@ -135,6 +138,7 @@ sub call {
 
 # for CoW-friendliness, MOOOOO!
 sub preload {
+	my ($self) = @_;
 	require PublicInbox::Feed;
 	require PublicInbox::View;
 	require PublicInbox::SearchThread;
@@ -147,6 +151,9 @@ sub preload {
 			PublicInbox::NewsWWW)) {
 		eval "require $_;";
 	}
+	if (ref($self)) {
+		$self->stylesheets_prepare($_) for ('', '../', '../../');
+	}
 }
 
 # private functions below
@@ -464,4 +471,120 @@ sub get_attach {
 	PublicInbox::WwwAttach::get_attach($ctx, $idx, $fn);
 }
 
+# User-generated content (UGC) may have excessively long lines
+# and screw up rendering on some browsers, so we use pre-wrap.
+#
+# We also force everything to the same scaled font-size because GUI
+# browsers (tested both Firefox and surf (webkit)) uses a larger font
+# for the Search <form> element than the rest of the page.  Font size
+# uniformity is important to people who rely on gigantic fonts.
+# Finally, we use monospace to ensure the Search field and button
+# has the same size and spacing as everything else which is
+# <pre>-formatted anyways.
+our $STYLE = 'pre{white-space:pre-wrap}*{font-size:100%;font-family:monospace}';
+
+sub stylesheets_prepare ($$) {
+	my ($self, $upfx) = @_;
+	my $mini = eval {
+		require CSS::Minifier;
+		sub { CSS::Minifier::minify(input => $_[0]) };
+	} || eval {
+		require CSS::Minifier::XS;
+		sub { CSS::Minifier::XS::minify($_[0]) };
+	} || sub { $_[0] };
+
+	my $css_map = {};
+	my $stylesheets = $self->{pi_config}->{css} || [];
+	my $links = [];
+	my $inline_ok = 1;
+
+	foreach my $s (@$stylesheets) {
+		my $attr = {};
+		local $_ = $s;
+		foreach my $k (qw(media title href)) {
+			if (s/\s*$k='([^']+)'// || s/\s*$k=(\S+)//) {
+				$attr->{$k} = $1;
+			}
+		}
+
+		if (defined $attr->{href}) {
+			$inline_ok = 0;
+		} else {
+			open(my $fh, '<', $_) or do {
+				warn "failed to open $_: $!\n";
+				next;
+			};
+			my ($key) = (m!([^/]+?)(?:\.css)?\z!i);
+			my $ctime = 0;
+			my $local = do { local $/; <$fh> };
+			if ($local =~ /\S/) {
+				$ctime = sprintf('%x',(stat($fh))[10]);
+				$local = $mini->($local);
+			}
+			$css_map->{$key} = $local;
+			$attr->{href} = "$upfx$key.css?$ctime";
+			if (defined($attr->{title})) {
+				$inline_ok = 0;
+			} elsif (($attr->{media}||'screen') eq 'screen') {
+				$attr->{-inline} = $local;
+			}
+		}
+		push @$links, $attr;
+	}
+
+	my $buf = "<style>$STYLE";
+	if ($inline_ok) {
+		my @ext; # for media=print and whatnot
+		foreach my $attr (@$links) {
+			if (defined(my $str = delete $attr->{-inline})) {
+				$buf .= $str;
+			} else {
+				push @ext, $attr;
+			}
+		}
+		$links = \@ext;
+	}
+	$buf .= '</style>';
+
+	if (@$links) {
+		foreach my $attr (@$links) {
+			delete $attr->{-inline};
+			$buf .= "<link\ntype=text/css\nrel=stylesheet";
+			while (my ($k, $v) = each %$attr) {
+				$v = qq{"$v"} if $v =~ /[\s=]/;
+				$buf .= qq{\n$k=$v};
+			}
+			$buf .= ' />';
+		}
+		$self->{"-style-$upfx"} = $buf;
+	} else {
+		$self->{-style_inline} = $buf;
+	}
+	$self->{-css_map} = $css_map;
+}
+
+# returns an HTML fragment with <style> or <link> tags in them
+# Called by WwwStream by nearly every HTML page
+sub style {
+	my ($self, $upfx) = @_;
+	$self->{-style_inline} || $self->{"-style-$upfx"} || do {
+		stylesheets_prepare($self, $upfx);
+		$self->{-style_inline} || $self->{"-style-$upfx"}
+	};
+}
+
+# /$INBOX/$KEY.css endpoint
+# CSS is configured globally for all inboxes, but we access them on
+# a per-inbox basis.  This allows administrators to setup per-inbox
+# static routes to intercept the request before it hits PSGI
+sub get_css ($$) {
+	my ($self, $key) = @_;
+	my $css_map = $self->{-css_map} || stylesheets_prepare($self, '');
+	defined(my $css = $css_map->{$key}) or return r404();
+	my $h = [ 'Content-Length', bytes::length($css),
+		'Content-Type', 'text/css' ];
+	PublicInbox::GitHTTPBackend::cache_one_year($h);
+	[ 200, $h, [ $css ] ];
+}
+
 1;
diff --git a/lib/PublicInbox/WwwStream.pm b/lib/PublicInbox/WwwStream.pm
index e548f00f..c3aeb6b0 100644
--- a/lib/PublicInbox/WwwStream.pm
+++ b/lib/PublicInbox/WwwStream.pm
@@ -65,7 +65,7 @@ sub _html_top ($) {
 	"<html><head><title>$title</title>" .
 		"<link\nrel=alternate\ntitle=\"Atom feed\"\n".
 		"href=\"$atom\"\ntype=\"application/atom+xml\"/>" .
-		PublicInbox::Hval::STYLE .
+	        $ctx->{www}->style($upfx) .
 		"</head><body>". $top . $tip;
 }
 
-- 
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