Localization using ex_cldr

I am using phoenix 1.5.

I am not sure If I understand correctly but phoenix is able to detect the parameter, this is what I saw in server logs Parameters: %{"locale" => "en"} when I request http://localhost:4000/en and path_params: %{"locale" => "en"} is in conn. I have from: [:path, :query] in SetLocale plug. All ex_cldr variables in conn are set to use fa. I don’t know how to further investigate that.