Documented url_for() in before_dispatch

lib/Mojolicious/Plugin/RequestBase.pm

@@ -62,6 +62,23 @@ and a request sent to Request to C<https://example.com/myapp/foo>:
   # https://example.com/foo (Probably not what you want)
   $c->req->url->to_abs;
 
+=head2 Hooks
+
+=head2 before_dispatch
+
+In a L<before_dispatch|Mojolicious/HOOKS> the router has not yet started,
+so you need to pass in the request path to get the expected result:
+
+  hook before_dispatch => sub {
+    my $c = shift;
+
+    # https://example.com/myapp/foo
+    $c->url_for($c->req->url->path)->to_abs;
+
+    # https://example.com/foo (Probably not what you want)
+    $c->url_for->to_abs;
+  };
+
 =head1 DESCRIPTION
 
 Simple plugin to support Request Base header. Just load it and set

t/basic.t

@@ -5,8 +5,15 @@ use Test::More;
 use Mojolicious::Lite;
 use Test::Mojo;
 
+my @before;
+
 plugin 'RequestBase';
 
+hook before_dispatch => sub {
+  my $c = shift;
+  @before = ($c->url_for->to_abs, $c->url_for($c->req->url->path)->to_abs);
+};
+
 get '/' => sub {
   my $c = shift;
   $c->render(text => $c->url_for('login'));
@@ -53,4 +60,7 @@ $t->get_ok('/some/path', {'X-Request-Base' => 'http://example.com/foo'})
   ->status_is(200)->json_is('/abs_canonicalize', '/foo/some/path')
   ->json_is('/canonicalize', '/some/path');
 
+is $before[0], "http://example.com/foo",           "before_dispatch url_for";
+is $before[1], "http://example.com/foo/some/path", "before_dispatch url";
+
 done_testing;