金融庁の暗号資産交換業者一覧のPDFが更新されていないか確認し、更新されていればSlackに通知する

code.gs

var SLACK_USER_ID_TO_NOTICE = PropertiesService.getScriptProperties().getProperty("SLACK_USER_ID_TO_NOTICE")
var SLACK_WEBHOOK_URL = PropertiesService.getScriptProperties().getProperty("SLACK_WEBHOOK_URL")
var SLACK_CHANNEL = PropertiesService.getScriptProperties().getProperty("SLACK_CHANNEL")
var SLACK_BOT_NAME = PropertiesService.getScriptProperties().getProperty("SLACK_BOT_NAME")
var DIGEST_PROPERTY_KEY = "DIGEST_PROPERTY_KEY"

function main() {
  var url = "https://www.fsa.go.jp/menkyo/menkyoj/kasoutuka.pdf"
  var pdf = UrlFetchApp.fetch(url).getAs('application/pdf')
  var bytes = pdf.getBytes
  var digest = MD5_(bytes)

  var scriptProperties = PropertiesService.getScriptProperties();
  var previous_digest = scriptProperties.getProperty(DIGEST_PROPERTY_KEY)
  if (digest == previous_digest) {
    return
  } else {
    scriptProperties.setProperty(DIGEST_PROPERTY_KEY, digest)
    sendToSlack_(SLACK_USER_ID_TO_NOTICE + "金融庁 暗号資産交換業者登録一覧 が更新されました\n" + url);
    return
  }
}

function MD5_ (input) {
  var rawHash = Utilities.computeDigest(Utilities.DigestAlgorithm.MD5, input, Utilities.Charset.UTF_8);
  var txtHash = '';
  for (i = 0; i < rawHash.length; i++) {
    var hashVal = rawHash[i];
    if (hashVal < 0) {
      hashVal += 256;
    }
    if (hashVal.toString(16).length == 1) {
      txtHash += '0';
    }
    txtHash += hashVal.toString(16);
  }
  return txtHash;
}

function sendToSlack_(message) {
  var url = SLACK_WEBHOOK_URL;
  var data = { 
    "channel" : SLACK_CHANNEL,
    "username" : SLACK_BOT_NAME,
    "text" : message,
    //"unfurl_links": true,
  };
  var payload = JSON.stringify(data);
  var options = {
    "method" : "POST",
    "contentType" : "application/json",
    "payload" : payload
  };
  return UrlFetchApp.fetch(url, options);
}