Restify formatters not called

Question

I'm trying to use a formatter with Restify in NodeJS. This is the code:

var restify = require('restify')
var utils = require('util')

function f1(req, res, next) {
    res.json({ 
        number: 1, 
        name: 'John', 
        gender: 'male'
      });     
      next()
}

var server = restify.createServer({
    formatters: {
        'application/bash': function f2(req, res, body) {
            var ret = "";
            console.log("Hi, I'm in the formatters ")
            for(var propertyName in body) {
               ret += utils.format("%s=%s ", propertyName, body[propertyName]);
            }
            return ret.trim();
        }
    }
});

server.get('/', f1);

server.listen(8080, function() {
  console.log('%s listening at %s', server.name, server.url);
});

if I make a GET request setting Content-Type to application/bash, i get the json object instead of something like "key=value key=value..." and a content type setted to application/json. Also i didn't see the console.log(). How can i fix it? Where is the bug?