Google Apps Script to use ChatGPT API

ChatGPT.js

function doPost(e) {
  // slack appsのEvent Subscriptionsのchallenge。同期する時に利用。
  var params = JSON.parse(e.postData.getDataAsString());
  if('challenge' in params)
  {
    return ContentService.createTextOutput(params.challenge);
  }

  // ユーザ名とtextを取得
  var userName = params.event.user;
  var textSlack = params.event.text.substr(0, params.event.text.length);

  // chatGPTに問い合わせ
  var resultStr = getChatGptMessage(textSlack);
　var contents = `<@${userName}> ${resultStr}`;

  var options =
  {
    "method" : "post",
    "contentType" : "application/json",
    "payload" : JSON.stringify(
      {
        "text" : contents,
        link_names: 1
      }
    )
  };
  // slack連携
  UrlFetchApp.fetch(YOUR_SLACK_WEBHOOK_URL, options);
}

// ChatGPTのAPIを呼び出し応答を取得する
function getChatGptMessage(message) {
  var uri = 'https://api.openai.com/v1/chat/completions';
  var headers = {
    'Authorization': `Bearer ${ScriptProperties.getProperty("OPENAI_API_KEY")}`,
    'Content-type': 'application/json',
    'X-Slack-No-Retry': 1
  };
  var options = {
    'muteHttpExceptions' : true,
    'headers': headers, 
    'method': 'POST',
    'payload': JSON.stringify({
      model: "gpt-3.5-turbo",
      messages: [
        {role: "user", content: message}
      ]
    })
  };
  console.log(options)
  try {    
      const response = UrlFetchApp.fetch(uri, options);
      var json = JSON.parse(response.getContentText());
      let generatedText = json["choices"][0]['message']['content'];
      console.log(generatedText);
      return generatedText;
  } catch(e) {
    console.log('error');
  }
}