get_farmer_log.js

    self.get_farmer = function(username) {
        var p = self.api_call("farmer/", {
            actor__user__username: username
        });
        p.add_callback(function(result){
        	return im.log(result);
        });
        p.add_callback(function(result){
            if (result.objects.length === 0){
                return null;
            } else {
                return result.objects[0];
            }
        });
        return p;
    };

Lines 5-6 do completely the wrong thing. im.log() returns the result of logging -- i.e. whether logging succeeded or not. You want to pass the original result on.