Notify tenki.jp weather to Slack using Google Apps Script

slack-rain-notify.gs

// GAS Script for weather daemon on Slack

// ScriptProperties:
// - weatherUrl: Local weather web page URL on tenki.jp
// - slackHookUrl: Slack web hook URL
// - slackChannel: Channel name of Slack

function rainRetrieve() {
  var url = PropertiesService.getScriptProperties().getProperty("weatherUrl");
  var res = UrlFetchApp.fetch(url);
  var content = res.getContentText();

  // get weather text
  var index = content.search(/"forecast_point_entry">/i);
  if (index < 0) {
    return;
  }
  var point = content.substring(index + 23);
  point = point.substring(0, point.search(/<\/tr>/));
  var weather = point.substring(point.search(/fs_m3">/) + 7);
  weather = weather.substring(0, weather.search(/<\//));
  var m = point.substring(point.search(/forecast_point_precip/));
  m = m.substring(m.search(/">/) + 2);
  m = m.substring(0, m.search(/<\//));
  m = parseInt(m, 10);
  var t = point.substring(point.search(/forecast_point_hour/));
  t = t.substring(t.search(/">/) + 2);
  t = t.substring(0, t.search(/<\//));
  var rain = false;
  var text = "";
  if (m > 0 || weather.search(/雨/) >= 0) {
    rain = true;
    text = "<" + url + "|" + t + "> :umbrella:" + weather + " " + m + "mm";
  } else {
    text = "<" + url + "|" + t + "> :sunny:" + weather;
  }
  Logger.log(text);
  var norain = PropertiesService.getScriptProperties().getProperty("norain");
  if (rain) {
    PropertiesService.getScriptProperties().deleteProperty("norain");
    var prem = PropertiesService.getScriptProperties().getProperty("rainm");
    PropertiesService.getScriptProperties().setProperty("rainm", m);
    if (norain || (prem && parseInt(prem, 10) < m)) {
      sendNotify(text);
    }
  } else {
    PropertiesService.getScriptProperties().setProperty("norain", text);
    if (!norain) {
      sendNotify(text);
    }
  }
}

function sendNotify(text) {
  var channel = PropertiesService.getScriptProperties().getProperty("slackChannel");
  var url = PropertiesService.getScriptProperties().getProperty("slackHookUrl");
  var payload = {"channel": "#" + channel, "username": "weather daemon", "text": text};
  var params = {"method": "POST", "payload": JSON.stringify(payload)};
  var res = UrlFetchApp.fetch(url, params);
  if (res) {
    return true;
  } else {
    return false;
  }
}