If you have a fairly large Google Site, and you make mistakes like we all do, at some point you’ll need to do a mass update to all the pages. It happened to me yesterday. I host a gadget on most of my pages see (Displaying analytics data on site pages), which I had accidentally deleted a while ago. I host it on Drive, so when I deleted it, I actually only moved it to my trash.

When you host something on Drive, it takes the url https://googledrive.com/host/fileid , so it actually still continues to work from the trash bin. Yesterday I thought it was time to clean out my trash so I permanently deleted everything, including the hosted gadget – so every page on this site started showing an error where the missing gadget used to be.

Luckily I had the source for the gadget on GitHub, so I could easily recreate it, but the problem with using Drive as a host is that the fileid is a oneoff thing – meaning that I cannot just create another file with the same id.

So I was faced with either manually editing each of 700+ pages on this site and reinserting a new gadget, or patching up the existing gadget with the new fileid.

Here’s a snippet to do it.

DANGER and IMPORTANT – make sure you do lots of checking on what will be changed before actually doing the setHtmlContent() . This could mess up your site if you replace the wrong thing with the wrong thing. NOTE also that some deprecated gadgets will stop working when rewritten. For example , those old Adsense gadgets that Google deprecated on Sites. If your page gets rewritten and you still have some of them on your site – they will disappear forever. If you have gadgets on your site, test thoroughly that they will not be screwed up by rewriting the html before running.

All I had to do was set the old fileId

var searchRx = /0B92ExLh4POiZT081dWl6WjdwbFk/g;

And the new one

var replaceWith = "0B92ExLh4POiZb19Qc3hidFgzS2M";

Always worth giving it a trial run first by setting this to false

var actuallyDoIt = true;
function patch() {
  
  // set this to true to actually do the update as opposed to just reporing it
  var actuallyDoIt = false;
  
  // this is the site i'm working with
  var site = SitesApp.getSite("mcpher.com", "share");
  
  // get all the pages on the site
  var pages = getPages(site);
  
  // get all the pages that contain the search term in their html
  var searchRx = /0B92ExLh4POiZT081dWl6WjdwbFk/g;
  var workingPages = pages.reduce (function (p,c) {
    var html = c.getHtmlContent();
    // if its a target page then select it and avoid getting the html again later
    if (html.search (searchRx , html) >=0) {
      p.push ({html:html, page:c});
    }
    return p;
  },[]);
  
  
  //now we'll update these pages with the replacement value
  var replaceWith = "0B92ExLh4POiZb19Qc3hidFgzS2M";
  workingPages.forEach (function (d,i) {
    Logger.log (""+i+" "+(actuallyDoIt ? "updating " : "would have updated ") + d.page.getUrl());
    
    // REMEMBER TO DO LOTS OF LOGGING AND CHECKING HERE BEFORE SETTING ACTUALLYDOIT TO TRUE
    if (actuallyDoIt) {
      d.page.setHtmlContent ( d.html.replace (searchRx, replaceWith) );
    }
  });
  
}

/**
 * get all the pages on my site - into a heirach object
 * @param {Site} site the site
 * @param {number} optMax max number of pages to go for
 * @param {string} optQuery a search query (unfortunately this doesnt search html)
 * @param {number} optStart you can start later - useful for restarting if you run out of execution time
 * @return {Array.Page} all the pages on the site
 **/
function getPages(site,optMax,optQuery,optStart) {
  
  var chunk,pages = [], options = {};
  do {
    options.start= pages.length + (optStart || 0);
    if (optMax) options.max =  optMax - pages.length ;
    if (optQuery) options.search = optQuery;
    chunk = cUseful.rateLimitExpBackoff( function (){
      return site.getAllDescendants(options);
    });
    cUseful.arrayAppend(pages, chunk);
  }
  while (chunk.length && (!optMax || pages.length 

For this snippet you'll need my cUseful library. You can find the details below or get it from github.

For more like this see Google Apps Scripts Snippets
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