Google Apps Script Cache Util. Will cache values for 6 hours.

cache.js

// Comfotability util for easy caching using Apps Script DocumentCache.
// Uses md5 for cache keys.
// See: https://developers.google.com/apps-script/reference/cache/cache

var CACHE_INTERVAL = 21600;

var docCache = CacheService.getDocumentCache();

function cacheSet(key, val){
  return dcache.put(md5(key), JSON.stringify(val), CACHE_INTERVAL); // Max is: 21600 = 6hours
}

function cacheGet(key){
  return JSON.parse(dcache.get(md5(key)));
}

function md5(str){
  return Utilities.computeDigest(Utilities.DigestAlgorithm.MD5, str)
  .map(function(b) {return ("0" + (b < 0 && b + 256 || b).toString(16)).substr(-2)})
  .join("");
}

function get(url){
  var res = cacheGet(url);
  if(!res){
    var httpRes = UrlFetchApp.fetch(url, {muteHttpExceptions:true});
    res = JSON.parse(httpRes.getContentText());
    if(httpRes.getResponseCode() == 200){
      cacheSet(url, res); 
    } else {
      throw "HHTP Get Error: " + res.message
      return;
    }
  }
  return res;
}