[#1048] Add a no_cache argument to DW::Routing

This (on apache, at least), will add Cache-control: no-cache, and
Pragma: no-cache

cgi-bin/DW/Request.pm

@@ -241,6 +241,10 @@ Spawn off an external program.
 
 Redirect to a different URL.
 
+=head2 C<< $r->no_cache >>
+
+Turn off caching for this resource.
+
 =head1 AUTHORS
 
 =over

cgi-bin/DW/Request/Apache2.pm

@@ -306,4 +306,9 @@ sub spawn {
     return $self->{r}->spawn_proc_prog( @_ );
 }
 
+sub no_cache {
+    my DW::Request::Apache2 $self = shift;
+    return $self->{r}->no_cache( 1 );
+}
+
 1;

cgi-bin/DW/Request/Standard.pm

@@ -297,4 +297,7 @@ sub spawn {
     confess "Sorry, spawning not implemented.";
 }
 
+sub no_cache {
+    confess "Sorry, no_cache not implemented.";
+}
 1;

cgi-bin/DW/Routing.pm

@@ -217,6 +217,9 @@ sub _call_hash {
     $r->content_type( $default_content_types->{$format} )
         if $default_content_types->{$format};
 
+    # apply no-cache if needed
+    $r->no_cache if $opts->no_cache;
+
     # try to call the handler that actually does the content creation; it will
     # return either a number (HTTP code), or undef
     # means there was an error of some sort
@@ -596,6 +599,7 @@ sub _apply_defaults {
     $hash->{api}          = $opts->{api}  || 0;
     $hash->{format}     ||= $opts->{format} || 'html';
     $hash->{prefer_ssl}   = $opts->{prefer_ssl} || 0;
+    $hash->{no_cache}     = $opts->{no_cache} || 0;
 
     my $formats = $opts->{formats} || [ $hash->{format} ];
     $formats = { map { ( $_, 1 ) } @$formats } if ref $formats eq 'ARRAY';

cgi-bin/DW/Routing/CallInfo.pm

@@ -158,6 +158,13 @@ Should prefer SSL if possible.
 
 sub prefer_ssl { return $_[0]->{__hash}->{prefer_ssl} || 0; }
 
+=head2 C<< $self->no_cache >>
+
+Return whether we should prevent caching or not.
+
+=cut
+sub no_cache { return $_[0]->{__hash}->{no_cache} || 0; }
+
 =head2 C<< $self->subpatterns >>
 
 Return the regex matches.