From e1c7d5442ca1d3bd67c200d2dbd94bd0e40e72bd Mon Sep 17 00:00:00 2001
From: root <root@rbsd.ankarstrom.se>
Date: Mon, 26 Apr 2021 12:26:06 +0000
Subject: Use single hyphen for NULL value, allow the user to specify it

This lets the user inject a footer without injecting a header.
---
 lib/Apache/Inject.pm         | 76 +++++++++++++++++++++++++++++---------------
 lib/Apache/Inject/Handler.pm | 14 ++++----
 2 files changed, 58 insertions(+), 32 deletions(-)

(limited to 'lib')

diff --git a/lib/Apache/Inject.pm b/lib/Apache/Inject.pm
index 2c05b14..09bf18a 100644
--- a/lib/Apache/Inject.pm
+++ b/lib/Apache/Inject.pm
@@ -11,35 +11,31 @@ use Apache2::Const qw/OR_LIMIT OR_AUTHCFG TAKE12/;
 use Apache2::Log ();
 use Apache2::Module ();
 
-my @directives = (
-	{ name => 'Inject',
-	  func => __PACKAGE__.'::Inject',
-	  req_override => OR_LIMIT|OR_AUTHCFG,
-	  args_how => TAKE12,
-	  errmsg => 'Inject HeadFile[!] FootFile[!]' }
-);
+my @directives = ({
+	name => 'Inject',
+	func => __PACKAGE__.'::Inject',
+	req_override => OR_LIMIT|OR_AUTHCFG,
+	args_how => TAKE12,
+	errmsg => 'Inject HeadFile[!] FootFile[!]',
+});
 Apache2::Module::add(__PACKAGE__, \@directives);
 
 sub Inject {
 	my ($self, $parms, @args) = @_;
 
-	for (@args) {
-		if ($_ eq ' ') {
-			$parms->server->log_error('Inject: Argument cannot be a single space');
-		}
-	}
-
 	# Construct directives for passing arguments to handler
 	my $head = $args[0];
-	my $foot = $args[1] || ' '; # single space signifies absence of argument
+	my $foot = $args[1] || '-'; # single hyphen signifies absence of argument
 	$head =~ s/\\/\\\\/; s/"/\\"/;
 	$foot =~ s/\\/\\\\/; s/"/\\"/;
 
 	# Add relevant directives to current configuration
-	$parms->add_config(['SetHandler perl-script',
-	                    'PerlResponseHandler Apache::Inject::Handler',
-	                    qq{PerlSetVar InjectHead "$head"},
-	                    qq{PerlSetVar InjectFoot "$foot"}]);
+	$parms->add_config([
+		'SetHandler perl-script',
+		'PerlResponseHandler Apache::Inject::Handler',
+		qq{PerlSetVar InjectHead "$head"},
+		qq{PerlSetVar InjectFoot "$foot"},
+	]);
 }
 
 1;
@@ -54,11 +50,23 @@ Apache::Inject - Apache directive for injecting HTML headers and footers
 
   LoadModule perl_module libexec/apache24/mod_perl.so
   PerlLoadModule Apache::Inject
-  DocumentRoot /uar/local/www/apache24/data
+  DocumentRoot /usr/local/www/apache24/data
+
   <Directory /usr/local/www/apache24/data>
+      # Inject both header and footer on all pages on the server
       Inject head.html foot.html
   </Directory>
 
+  <Location /blog>
+      # Inject only header on pages under /blog
+      Inject head.html
+  </Location>
+
+  <Files index.html>
+      # Inject only footer on pages named index.html
+      Inject - foot.html
+  </Files>
+
 =head1 DESCRIPTION
 
 Apache::Inject is a mod_perl module that adds an Apache directive
@@ -129,6 +137,30 @@ an unprivileged user and will be skipped if they are run as root.
 This is relevant if you install Apache::Inject via App::Cpan, which
 normally runs as root.
 
+=head1 SYNTAX
+
+The Inject directive takes one or two arguments:
+
+  Inject HEADER_FILE [FOOTER_FILE]
+
+Each argument can consist of one of two things:
+
+=over
+
+=item 1.
+the path to a file relative to the document root, or
+
+=item 2.
+a single hyphen (C<->), signifying the absence of an argument.
+
+=back
+
+Passing a hyphen as the first argument disables the header, and
+passing a hyphen as the second argument disables the footer.
+
+If you leave out the second argument, then it is implicitly equivalent
+to a hyphen.
+
 =head1 OPERATION
 
 Behind the scenes, the Inject directive works as an alias for
@@ -160,12 +192,6 @@ Apache handle it as it would if the Inject directive were not used.
 
 =over
 
-=item Error: Argument cannot be a single space
-
-In the current implementation, the file names given to Inject are
-not allowed to consist solely of a single space, as this is a special
-value signifying the absence of an argument.
-
 =item Error: InjectHead/InjectFoot should not begin with slash, as
 it is already always relative to document root
 
diff --git a/lib/Apache/Inject/Handler.pm b/lib/Apache/Inject/Handler.pm
index f9254fd..0e054e7 100644
--- a/lib/Apache/Inject/Handler.pm
+++ b/lib/Apache/Inject/Handler.pm
@@ -12,14 +12,14 @@ use Apache2::RequestUtil ();
 my $doc = qr{
 	\A
 	(?<head> \s*
-	         (<!doctype[^>]*>)? \s*
-	         (<html[^>]*>)? \s*
-	         ( <head[^>]*>.*?</head> \s*
+	         ( <!doctype[^>]*> )? \s*
+	         ( <html[^>]*> )? \s*
+	         ( <head[^>]*> .*? </head> \s*
 	         | ( <meta[^>]*> \s*
 	           | <link[^>]*> \s*
-	           | <title[^>]*>.*?</title> \s*
-	           | <style[^>]*>.*?</style> \s* # n.b.
-	           | <script[^>]*>.*?</script> \s* # n.b.
+	           | <title[^>]*> .*? </title> \s*
+	           | <style[^>]*> .*? </style> \s*
+	           | <script[^>]*> .*? </script> \s*
 	           | <base[^>]*> \s*
 	           )+
 	         )?
@@ -57,7 +57,7 @@ sub inject {
 
 	# Retrieve value implicitly set by Inject directive
 	return if not (my $val = $r->dir_config($var));
-	return if $val eq ' '; # special value signifying absence of argument
+	return if $val eq '-'; # special value signifying absence of argument
 
 	# Validate path
 	if ($val =~ m{^/}) {
-- 
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