Support » Plugin: WebP Express » Tests succeed, but PHP errors abound and site images not converting

  • I’m working with WPEngine support to try to get this plugin working and they’ve set up the nginx rules, but am having trouble getting images to convert. Sampling of PHP errors:

    [Tue Dec 11 19:56:50.134358 2018] [php7:error] [pid 7963] [client] PHP Fatal error: Uncaught Error: Class 'WebPConvert\\Converters\\' not found in /nas/content/live/emdev/wp-content/plugins/webp-express/test/test-run.php:71\nStack trace:\n#0 /nas/content/live/emdev/wp-content/plugins/webp-express/test/test-run.php(100): getConverterOptionsFromQueryString(NULL)\n#1 {main}\n thrown in /nas/content/live/emdev/wp-content/plugins/webp-express/test/test-run.php on line 71, referer:

    [Tue Dec 11 18:22:05.647141 2018] [php7:notice] [pid 19502] [client] PHP Notice: Undefined index: source in /nas/content/live/emdev/wp-content/plugins/webp-express/test/test-run.php on line 46, referer:

    I’ve got EWWW and Gd running and tests seem successful… Screenshots: and

    Any ideas what to try?

    The page I need help with: [log in to see the link]

Viewing 5 replies - 16 through 20 (of 20 total)
  • Thread Starter adamwking


    Victory! On WP Engine, WebP is now being served after upgrading to 0.81 and putting in the new nginx rules

    if ($http_accept ~* "webp"){
      rewrite ^/(.*).(jpe?g|png)$ /wp-content/plugins/webp-express/wod/webp-on-demand.php?xsource=x$request_filename&wp-content=wp-content break;

    Thanks so so much for your work on this, @roselldk!

    • This reply was modified 5 years, 2 months ago by adamwking. Reason: typo
    Plugin Author


    Great way to start the weekend 🙂 Cheers

    I’m currently working with WPEngine to get WebP Express to work with their CDN solution – will keep you posted 🙂

    Has anyone figured out how to get the plugin to work on WPengine?! So frustrating.

    Thread Starter adamwking


    WPEngine ended up removing the WebP Express nginx rules we set up as part of this thread as it was overloading the server. 504 and 427 errors were abounding and we couldn’t figure out a fix. At first they couldn’t figure out where the problem was coming from other than there seemed to be a lot of calls being made to “heartbeat”. At first we thought it was unrelated to WebP Express, then I thought maybe it was because EWWW Cloud Optimizer’s connection had lapsed and the processing was happening on the server via the Gd extension fallback. But ultimately the problem kept getting worse, and this is what their support folks had to say when they finally thought they’d pinpointed it and removed the nginx rule:

    The site appears to be running a large amount of GET calls that are producing numerous 504s. The issue is with with the “WebP Express”, as I see there is an nginx rule in place to take every JPG and PNG file and rewrite the URLs to:

    This is causing apache to load each image and will eventually start 504’ing with more images loading on the page. Based on this, I highly recommend we remove this nginx rule from your install.

    We have now removed the Nginx Rule that was used for WebP Express. This in turn will reduce the strain on Apache and prevent any 504s it was previously causing.

    I’ve still got WebP Express configured and running on another WPengine site, and it seems to be working now that I turned on AlterHTML with <picture>, but certain JPEGs aren’t rendering (in the case I’m seeing right now, it’s a jpg background-image tag inserted with an inline style.) Also, visiting any image URL directly (eg.×853.png) doesn’t load an image, but instead shows the error “It seems you are visiting this file (plugins/webp-express/wod/webp-on-demand.php) directly. We do not allow this.” So maybe WPE is starting to actively block WebP Express? Unsure. About to ask their support about it.

Viewing 5 replies - 16 through 20 (of 20 total)
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