Content negotiation

[darvin]

From my understanding it's impossible to do via connect/express middleware, and it could be nice addition to zappa.
Say,

@get '/': ->
  @render index: {foo: 'bar'}

And if request has header Accept-type: application/json, server will respond with JSON {"foo":"bar"} instead of view index rendered with {foo:"bar"}
Will it be accepted into upstream? If yes, I can do that