purge from cdn on favorite changes

We should be purging the relevant tags when favorites are added or
removed. Currently, the front end does this, but it really should be
handled by the API server.

lib/MetaCPAN/Server/Controller/User/Favorite.pm

@@ -25,17 +25,18 @@ sub index : Path : ActionClass('REST') {
 sub index_POST {
     my ( $self, $c ) = @_;
     my $pause    = $c->stash->{pause};
-    my $req      = $c->req;
+    my $data     = $c->req->data;
     my $favorite = $c->model('CPAN::Favorite')->put(
         {
             user         => $c->user->id,
-            author       => $req->data->{author},
-            release      => $req->data->{release},
-            distribution => $req->data->{distribution},
-            author       => $req->data->{author},
+            author       => $data->{author},
+            release      => $data->{release},
+            distribution => $data->{distribution},
         },
         { refresh => 1 }
     );
+    $c->purge_author_key( $data->{author} )     if $data->{author};
+    $c->purge_dist_key( $data->{distribution} ) if $data->{distribution};
     $self->status_created(
         $c,
         location => $c->uri_for( join( '/',
@@ -50,6 +51,9 @@ sub index_DELETE {
         ->get( { user => $c->user->id, distribution => $distribution } );
     if ($favorite) {
         $favorite->delete( { refresh => 1 } );
+        $c->purge_author_key( $favorite->author )
+            if $favorite->author;
+        $c->purge_dist_key($distribution);
         $self->status_ok( $c,
             entity => $favorite->meta->get_data($favorite) );
     }