GuruNavi Elixir API example

guru_navi.ex

defmodule GuruNaviApi do

  def get_shops({addr, freeword}) do
    iget_shops({addr, freeword}, 1, [])
  end

  # ページング：最終ページ
  def iget_shops({_addr, _freeword}, _offset, [%{:last => true}|result] ) do
    result
  end

  def iget_shops({addr, freeword}, offset, res_state) do
    res =
      HTTPoison.get!(access_url("https://api.gnavi.co.jp/RestSearchAPI/20150630/",[
        "address="     <> addr,
        "freeword="    <> freeword,
        "hit_per_page="<> "50",
        "offset_page=" <> Integer.to_string(offset)
        # "range="<>"2",   # 1:300 2:500 3:1km 4:2km 5:3km
      ]) )
      |> parse_json
      |> case do
          %{"error" => e} -> IO.puts e
                             e
          res  -> # ヒット数=1の場合は、List化されていないのでリストにくるむ
              if is_list(res["rest"]) do
                res["rest"]
              else
                [res["rest"]]
              end
              |> Enum.map( fn r -> { r["name"], r["tel"], r["category"], r["opentime"] } end)
              |> case do shop_list -> [ shops:           shop_list ++
                                                         case res_state do
                                                           [] -> []
                                                           _  -> res_state[:shops]
                                                         end,
                                        total_hit_count: String.to_integer(res["total_hit_count" ]),
                                        hit_per_page:    String.to_integer(res["hit_per_page" ]),
                                        hit_count:       length(shop_list),
                                        offset:          offset,
                                      ] end
       end
       # ページング：残行カウント
       rest_count = res[:total_hit_count] - offset * res[:hit_per_page]
       # IO.puts rest_count
    iget_shops({addr, freeword}, offset+1, [%{:last => (rest_count <= 0)}] ++ res)
  end

  def access_url(url_base, opts\\[]) do
    api_key = Application.get_env(:groumet, :apis)[:guru_api_key]
    url_base
        <> "?"
        <> Enum.join( [ "format="<>"json", "keyid="<>api_key ] ++ opts, "&")
  end

  defp parse_json( %HTTPoison.Response{status_code: 200, body: body} ) do
    body
    |> Poison.decode!
  end

  defp parse_json( %HTTPoison.Response{status_code: 492, body: body} ) do
    IO.puts "１日の利用制限に達しました"
    body
    |> Poison.decode!
  end
end