Can't post json in a Mojo::UserAgent request

Question

I can't get the following Mojo::UserAgent call to post JSON to the server:

use Mojo::UserAgent;
my $ua=Mojo::UserAgent->new;
my $json = $ua->post("localhost:6767" => {} => json =>{ val=>10 })->res->json;

Using a fake debug server on the other side with nc -l 6767 gives the following output:

POST / HTTP/1.1
User-Agent: Mojolicious (Perl)
Connection: keep-alive
Content-Length: 0
Host: localhost:6767 

It's not just the json method, the form, and the whole Transactor seems to be broken on 2 of my machines. From the docs:

perl -MMojo::UserAgent::Transactor -E 'say Mojo::UserAgent::Transactor->new->tx(PUT => "http://kraih.com" => json => {a => "b"})->req->to_string;'
PUT / HTTP/1.1
Content-Length: 4
Host: kraih.com

json

Hard to believe my eyes. What am I missing?

Answer 1

Are all of your boxes using Mojolicious 3.85 or greater? The UA form/json generators are very new, only since 3.85 or 2013-02-13.

Also you might try removing the empty hashref (which would be for extra headers), unless there is some reason to have it there.