Elixir Language
IO.inspectとラベルによるデバッグの改善

前書き

備考

ラベルなし

url
  |> IO.inspect
  |> HTTPoison.get!
  |> IO.inspect
  |> Map.get(:body)
  |> IO.inspect
  |> Poison.decode!
  |> IO.inspect

これはコンテキストなしで多くの出力をもたらします：

"https://jsonplaceholder.typicode.com/posts/1"
%HTTPoison.Response{body: "{\n  \"userId\": 1,\n  \"id\": 1,\n  \"title\": \"sunt aut facere repellat provident occaecati excepturi optio reprehenderit\",\n  \"body\": \"quia et suscipit\\nsuscipit recusandae consequuntur expedita et cum\\nreprehenderit molestiae ut ut quas totam\\nnostrum rerum est autem sunt rem eveniet architecto\"\n}",
 headers: [{"Date", "Thu, 05 Jan 2017 14:29:59 GMT"},
  {"Content-Type", "application/json; charset=utf-8"},
  {"Content-Length", "292"}, {"Connection", "keep-alive"},
  {"Set-Cookie",
   "__cfduid=d56d1be0a544fcbdbb262fee9477600c51483626599; expires=Fri, 05-Jan-18 14:29:59 GMT; path=/; domain=.typicode.com; HttpOnly"},
  {"X-Powered-By", "Express"}, {"Vary", "Origin, Accept-Encoding"},
  {"Access-Control-Allow-Credentials", "true"},
  {"Cache-Control", "public, max-age=14400"}, {"Pragma", "no-cache"},
  {"Expires", "Thu, 05 Jan 2017 18:29:59 GMT"},
  {"X-Content-Type-Options", "nosniff"},
  {"Etag", "W/\"124-yv65LoT2uMHrpn06wNpAcQ\""}, {"Via", "1.1 vegur"},
  {"CF-Cache-Status", "HIT"}, {"Server", "cloudflare-nginx"},
  {"CF-RAY", "31c7a025e94e2d41-TXL"}], status_code: 200}
"{\n  \"userId\": 1,\n  \"id\": 1,\n  \"title\": \"sunt aut facere repellat provident occaecati excepturi optio reprehenderit\",\n  \"body\": \"quia et suscipit\\nsuscipit recusandae consequuntur expedita et cum\\nreprehenderit molestiae ut ut quas totam\\nnostrum rerum est autem sunt rem eveniet architecto\"\n}"
%{"body" => "quia et suscipit\nsuscipit recusandae consequuntur expedita et cum\nreprehenderit molestiae ut ut quas totam\nnostrum rerum est autem sunt rem eveniet architecto",
  "id" => 1,
  "title" => "sunt aut facere repellat provident occaecati excepturi optio reprehenderit",
  "userId" => 1}

ラベル付き

labelオプションを使用してコンテキストを追加すると、多くの場合役に立ちます。

url
  |> IO.inspect(label: "url")
  |> HTTPoison.get!
  |> IO.inspect(label: "raw http resonse")
  |> Map.get(:body)
  |> IO.inspect(label: "raw body")
  |> Poison.decode!
  |> IO.inspect(label: "parsed body")

url: "https://jsonplaceholder.typicode.com/posts/1"
raw http resonse: %HTTPoison.Response{body: "{\n  \"userId\": 1,\n  \"id\": 1,\n  \"title\": \"sunt aut facere repellat provident occaecati excepturi optio reprehenderit\",\n  \"body\": \"quia et suscipit\\nsuscipit recusandae consequuntur expedita et cum\\nreprehenderit molestiae ut ut quas totam\\nnostrum rerum est autem sunt rem eveniet architecto\"\n}",
 headers: [{"Date", "Thu, 05 Jan 2017 14:33:06 GMT"},
  {"Content-Type", "application/json; charset=utf-8"},
  {"Content-Length", "292"}, {"Connection", "keep-alive"},
  {"Set-Cookie",
   "__cfduid=d22d817e48828169296605d27270af7e81483626786; expires=Fri, 05-Jan-18 14:33:06 GMT; path=/; domain=.typicode.com; HttpOnly"},
  {"X-Powered-By", "Express"}, {"Vary", "Origin, Accept-Encoding"},
  {"Access-Control-Allow-Credentials", "true"},
  {"Cache-Control", "public, max-age=14400"}, {"Pragma", "no-cache"},
  {"Expires", "Thu, 05 Jan 2017 18:33:06 GMT"},
  {"X-Content-Type-Options", "nosniff"},
  {"Etag", "W/\"124-yv65LoT2uMHrpn06wNpAcQ\""}, {"Via", "1.1 vegur"},
  {"CF-Cache-Status", "HIT"}, {"Server", "cloudflare-nginx"},
  {"CF-RAY", "31c7a4b8ae042d77-TXL"}], status_code: 200}
raw body: "{\n  \"userId\": 1,\n  \"id\": 1,\n  \"title\": \"sunt aut facere repellat provident occaecati excepturi optio reprehenderit\",\n  \"body\": \"quia et suscipit\\nsuscipit recusandae consequuntur expedita et cum\\nreprehenderit molestiae ut ut quas totam\\nnostrum rerum est autem sunt rem eveniet architecto\"\n}"
parsed body: %{"body" => "quia et suscipit\nsuscipit recusandae consequuntur expedita et cum\nreprehenderit molestiae ut ut quas totam\nnostrum rerum est autem sunt rem eveniet architecto",
  "id" => 1,
  "title" => "sunt aut facere repellat provident occaecati excepturi optio reprehenderit",
  "userId" => 1}