Building an Ad-hoc HTTP Server

#file path -> soggy_waffle/lib/soggy_waffle/weather_api.ex
  @behavior SoggyWaffle.WeatherAPI.Behavior
  @spec get_forecast(String.t()) ::
          {:ok, map()} | {:error, reason :: term()}
  def get_forecast(city) when is_binary(city) do
    app_id = SoggyWaffle.api_key()
    query_params = URI.encode_query(%{"q" => city, "APPID" => app_id})
    url =
      "https://api.openweathermap.org/data/2.5/forecast?" <> query_params
    case HTTPoison.get(url) do
      {:ok, %HTTPoison.Response{status_code: 200} = response} ->
        {:ok, Jason.decode!(response.body)}
      {:ok, %HTTPoison.Response{status_code: status_code}} ->
        {:error, {:status, status_code}}
      {:error, reason} ->
        {:error, reason}
    end
  end