Changing a resource does not clear the cache for all the transforms

[ajoliveau]

Running on Craft 4.5.11.1 with the Cloudflare pluggin v2.0.2

I set the plugin up to clear the Cloudflare cache when a resource is updated. The main resource image is correctly purged, but all the transforms (crops, conversion, etc) is not.
I usually create transforms to have images available as webp, to resize them so they're used in srcsets, and to crop them depending on the focal point.

I shoud specify that they are not named assets, they're dynamically generated at runtime in Twig.
So if my "source" asset's url is uploads/spectacles/show_-NWI_fEElSZn3sx6wBmf_-full.jpg, I have transforms named like uploads/spectacles/_600x450_crop_center-center_85_none/2378715/show_-NWI_fEElSZn3sx6wBmf_-full.webp

If I go to the Utilities and manually purge the transform url, it works correctly.

I can try to build my own purging logic using your API methods, but shouldn't this be part of the resource purging feature ?

[bencroker]

I understand how you might think this should be automatically handled by the plugin, but it has no way of knowing about every existing image transform, especially since they can be create on-the-fly in the templates, so I’m not sure how to best handle this.

[ajoliveau]

Yep I understand it's a specific use-case, but is this one that is really so rare ?
I actually researched this, and it seems that Craft actually keeps track of all the transforms, even unnamed ones, in a specific DB table called imagetransformindex

Craft has a built-in logic to, when an asset is changed or deleted, find all the transforms associated to this asset and delete them in the filesystem. You can see the method that's called here : https://docs.craftcms.com/api/v4/craft-imagetransforms-imagetransformer.html#method-getallcreatedtransformsforasset

Unfortunately all this logic is private, and there's no way to reuse their functions and methods, but what I managed to do is to listen on the EVENT_BEFORE_INVALIDATE_ASSET_TRANSFORMS event, and manually copy all the code to get the list of transforms when Craft would delete them. Then I just call purgeUrls() on them.

Here is the code inside my module :

Event::on(
    ImageTransforms::class,
    ImageTransforms::EVENT_BEFORE_INVALIDATE_ASSET_TRANSFORMS,
    function($event) {
        $asset = $event->asset;
        $urlsToInvalidate = [];

        $transformIndexes = (new Query())
        ->select([
            'filename',
            'transformString',
        ])
        ->from([Table::IMAGETRANSFORMINDEX])
        ->where(['assetId' => $asset->id])
        ->all();

        $rootUrl = rtrim($asset->getVolume()->getTransformFs()->getRootUrl(), '/');
        $basePath = $asset->getVolume()->transformSubpath;
        $basePath = StringHelper::removeRight($basePath, '/');
        $basePath = ($basePath ? $basePath . DIRECTORY_SEPARATOR : '') . $asset->folderPath;

        foreach ($transformIndexes as $key => $transformIndex) {

            $subfolder = $transformIndex['transformString'];
            if (!empty($transformIndex['filename']) && $transformIndex['filename'] !== $asset->getFilename()) {
                $subfolder .= DIRECTORY_SEPARATOR . $asset->id;
            }

            $filename = $transformIndex['filename'] ?: $asset->getFilename();

            $path = $basePath . DIRECTORY_SEPARATOR . $subfolder . DIRECTORY_SEPARATOR . $filename;
            
            $url = $rootUrl . $path;

            $urlsToInvalidate[] = $url;
        }
        
        $return = Cloudflare::getInstance()->api->purgeUrls($urlsToInvalidate);
        Craft::info("Purged urls : ", 'custom-cf-purge');
        Craft::info($urlsToInvalidate, 'custom-cf-purge');
        Craft::info($return, 'custom-cf-purge');

    }    
);

It seems to work fine ! I still think this feature would be inside the scope of the plugin, it's nice to know it's doable at least :)

[bencroker]

You’re right, this does actually seem much more feasible given that Craft tracks all image transforms. Thanks for sharing your code, I’ll look into what it would take to add this to the plugin.

[ajoliveau]

Glad to hear that, thank you ! I can turn my code snippet above into a pull request if that can help.

[bencroker]

That’s ok, it’s a good starting point that I can reference but not yet sure how I’d integrate this.

[bencroker]

So after exploring, it turns out that we’re already doing something similar in Blitz:
https://github.com/putyourlightson/craft-blitz/blob/3d838a8332327c093821ddd5247621ee59dab5a8/src/helpers/SiteUriHelper.php#L291-L312

The main difference is that Blitz is specifically tracking changes to assets based on modified images. So I’ve gone with your suggested event, which takes effect when Assets are selected as purgeable elements, in 9a683fa

You can test this by running composer require "putyourlightson/craft-cloudflare:dev-develop as 2.1.0".

[bencroker]

Have you had a chance to test this yet, @ajoliveau?

[bencroker]

Released in 2.1.0.