Merge branch 'feature/static_304'

Changes

@@ -27,6 +27,8 @@
       files in addition to standard Dancer conf files (Jonathan Scott Duff)
     * PR #1269: Stash decoded body_parameters separately from those 
       in Plack::Request (Russell @veryrusty Jenkins)
+    * GH #1253: Static middleware should send 304 Not Modified to enable
+      intermediate level caching. (Russell @veryrusty Jenkins)
 
     [ DOCUMENTATION ]
     * GH #608: Remove extra general COPYRIGHT notice in Tutorial.

lib/Dancer2/Core/App.pm

@@ -11,9 +11,11 @@ use Sub::Quote;
 use File::Spec;
 use Module::Runtime    'use_module';
 
+use Plack::App::File;
 use Plack::Middleware::FixMissingBodyInRedirect;
 use Plack::Middleware::Head;
-use Plack::Middleware::Static;
+use Plack::Middleware::Conditional;
+use Plack::Middleware::ConditionalGET;
 
 use Dancer2::FileUtils 'path';
 use Dancer2::Core;
@@ -1368,14 +1370,19 @@ sub to_app {
     # FixMissingBodyInRedirect
     $psgi = Plack::Middleware::FixMissingBodyInRedirect->wrap( $psgi );
 
-    # Static content passes through to app on 404, conditionally applied.
-    # Construct the statis app to avoid a closure over $psgi
+    # Only add static content handler if requires
     if ( $self->config->{'static_handler'} ) {
-        $psgi = Plack::Middleware::Static->wrap(
-            $psgi,
-            path => sub { -f path( $self->config->{public_dir}, shift ) },
-            root => $self->config->{public_dir},
+        # Use App::File to "serve" the static content
+        my $static_app = Plack::App::File->new(
+            root         => $self->config->{public_dir},
             content_type => sub { $self->mime_type->for_name(shift) },
+        )->to_app;
+        # Conditionally use the static handler wrapped with ConditionalGET
+        # when the file exists. Otherwise the request passes into our app.
+        $psgi = Plack::Middleware::Conditional->wrap(
+            $psgi,
+            condition => sub { -f path( $self->config->{public_dir}, shift->{PATH_INFO} ) },
+            builder   => sub { Plack::Middleware::ConditionalGET->wrap( $static_app ) },
         );
     }
 

t/static_content.t

@@ -0,0 +1,30 @@
+use strict;
+use warnings;
+use utf8;
+
+use Test::More;
+use Plack::Test;
+use HTTP::Request::Common;
+
+{
+    package PublicContent;
+    use Dancer2;
+
+    set public_dir => 't/corpus/static';
+
+    get '/' => sub { return 'Welcome Home' };
+
+}
+
+my $test = Plack::Test->create( PublicContent->to_app );
+
+subtest 'public content' => sub {
+    my $res = $test->request( GET '/1x1.png' );
+    is $res->code, 200, "200 response";
+    my $last_modified = $res->header('Last-Modified');
+
+    $res = $test->request( GET '/1x1.png', 'If-Modified-Since' => $last_modified );
+    is $res->code, 304, "304 response";
+};
+
+done_testing();