CSS cache randomly generating 404

We have BB installed on Genesis child theme hosted on WP Engine.

We have had, for about a year, issues with CSS cacheing either being corrupt or 404s. How do we know? Testing.

  • We have screenshots and videos from users showing the CSS not loading on the site
  • We have have turned off any plugin that minimizes or caches files
  • We have disabled WP Engine CDN
  • We can download a page from the site and nail down the exact CSS file that would need to be missing or corrupt to display exactly has as it’s been documented by users. And that files is a BB file
  • We have searched through the logs and see 404s and find many references to some variation of the missing CSS in question. For example - www.allbound.com - [16/Sep/2019:17:42:26 +0000] “GET /wp-content/uploads/bb-plugin/cache/261a9494683e191ab9ca7b84781e553e-layout-bundle.css?ver= HTTP/1.0” 404 564 “https://www.allbound.com/news-and-media/david-guthrie-joins-allbounds-board-of-advisors/” “Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.132 Safari/537.36”

Anyone else had any issues with sporadic CSS cache 404s?

Any suggestions for other testing to be done here?

Looks like you fixed the problem. Am I correct? Was it the folder & files permission issue?

It is not resolved. We have no idea actual the cause, or how to fully replicate it. So we’re not at all sure of what the resolution would be.


add_filter( 'fl_theme_builder_assets_expire', function($time) {
    return strtotime( '+6 months' );
} );

By default themer clears the css cache once a month, in case you update any layouts… this will extend it to 6 months.

If your server cache is really aggressive and is caching your pages for over a month the css urls will become 404s …

Its either that or something is changing the pages layouts programmatically and not clearing the wpe cache when the layouts are updated so that could be causing the 404s

WP Engine has a 30 day cache, which to me sounds aggressive. I suppose I could also just write a script to clear out all cache every night from BB and WP Engine every night.

Is the BB cache clearing universal? Like does it clear all cache at the same time or is it individualized, based on the edit date of a template/module/etc.?

It deletes the themer bundle files.

You can change that filter to leave them there forever… until you manually clear the cache or update a layout.

I believe the bundle file is the one that is going missing (see the 404 error above.)

I can’t be the first person to run into this on WP Engine and BB. But I’m not finding a lot of chatter about it on the board.

Im afraid you are.

We used to see this issue with ultra aggressive cheap hosts using litespeed… rare now… i mean nothing in the last year kind of rare.

Ok, we’ll add in the filter and push the timeout to 6 months. And we’ll just monitor for 404s and see if this resolves it.

For this experiment to work, we need the cache to get generated and stop being re-generated without cause. If we are not editing the site, and if we the 6-month filter in place, we should see no new cache getting generated at some point, right?

Because we have a TON of new CSS cache in the last 24 hours. A ton of it. And on popular pages at that. So I’d think at some point we’d be fully cached and see no new cache.


Should I disable “Enable the Cache Clearing Tool”?

Case in point… the Pricing page on our site. It’s obviously a heavily visited page. But we’ve made no edits. However, the cache for that page regenerates daily. It’s updated itself twice since we added the “6-month” suggestion.

There is no reason at all for this cache to regenerate so frequently.

What else do I need to do to reduce this?

The generated css for pages and layouts only gets deleted when the page or layout is edited, or the entire folder is deleted using the clear cache button in the backend.

The 6 month suggestion just means the bundle files wont self delete for 6 months… you can change it to infinity if you like and they will never self delete, again clearing the cache will delete all of them, editing the same layout will also delete them.

Disabling the cache clear tool just means that when you publish a page or post BB will not attempt to clear the cache for your hosting, in this case wpengine, which is a step backwards because WPE will still have the cached page and you just updated the layout so you are guaranteed to generate 404s that way.

We have no idea of what custom code you might have, we also have 1000s of WPE users with no issues whatsoever so there is no generic fix im afraid aside from disabling whatever custom code you have that keeps deleting the cached css and js files … maybe you have debug mode enabled?

What impact would debug mode have? It has been off but I did turn it on yesterday out of curiosity.

A perfect example of the issue: the pricing page has not been edited in a good 4 weeks. No one was in the admin editing any templates or pages yesterday. Yet the BB css for the page was updated. And we also had a report of that page showing to a user with no CSS.

Perhaps a better option is to just never delete any cache. Deleting it doesn’t guarantee a user sees new CSS if the HTML is still pointing to older CSS files.

Can I add a filter/action and disable all CSS deletes?

Either wp debug or bb debug mode will force all css and js to be recompiled on EVERY pageload

Gotcha. It’s off now. So we’ll go back to monitoring the CSS to see if/when it stops getting regenerated because it’s not supposed to be getting regenerated. And I’ll dig into the plugin and if there is no filter in place to prevent cache deletion, I will just flat out comment out the line that does the deleting. Because we would rather have too many old cache files than missing CSS for any page view, ever.

It looks like I am going to just manually update line 843 in the delete_asset_cache() function to not delete CSS files.

if($type != ‘css’){
fl_builder_filesystem()->unlink( $info[ $type ] );

To be clear, this is not my preference either. But we have missing CSS that is cached in HTML being served up by WP Engine, regardless of the cause.

I’m am open to other solutions. So keep the ideas coming.

So wait you added the filter to keep the bundles for 6 months and after 3 days they were deleted?

Something or someone must be changing these layouts for them to be cleared like that. Have you looked at the simple history plugin?

Also I strongly suggest you dont edit core files unless you never want to update. We added a filesystem class for a reason :wink:
I wrote a POC plugin https://github.com/Pross/bb-fast-filesystem

Deleted? Well, I’m working on validating that. But I can tell you that new CSS/JS cache is getting generated on pages that shouldn’t need it. Like I have a popular page that was last edited 7 days ago, but it got some new cached CSS/JS today.

As for editing the core plugin files… if there is another way to have the plugin not delete cache, I’m all for it. I’d rather users get old CSS than no css.

There are only two times css gets deleted, when a layout is updated or the cache clear button is clicked. Thats why I said to install simple history, it’ll tell you when layouts are updated.

If a page suddenly has a new css, then a layout or module was changed on that page, there is no other reason.