POST json to rails server

If you are sending in the right headers, then you won't need to do "ActiveSupport::JSON.decode" -- rails will do that for you.

You'll need to set the following headers in your post.

Content-Type: application/json
Accept: application/json

A 422 means Unprocessable Entity --- generally that there was a validation failure.

You should be able to have. If you can't, then your headers aren't set correctly.

def create
  if user = User.authenticate(params["email"], params["password"])
    session[:user_id] = user.id
    render :json => "{\"r\": \"t\"}" + req
  else
    render :json => "{\"r\": \"f\"}"
  end
end