Move element/query recording out of the TemplateCaches service

[brandonkelly]

That way plugins could initiate their own template recorders, and use the resulting collections for their own purposes, unrelated to Craft's own caching system (for example, they could be used as Varnish dependencies).

[brandonkelly]

This is resolved for Craft 3.5. (8859124)

• Element queries now register cache invalidation tags based on the parameters that are set on them

  cms/src/elements/db/EntryQuery.php

  Lines 1009 to 1023 in 8859124

  	protected function cacheTags(): array
  	{
  	$tags = [];
  	// If the type is set, go with that instead of the section
  	if ($this->typeId) {
  	foreach ($this->typeId as $typeId) {
  	$tags[] = "entryType:$typeId";
  	}
  	} else if ($this->sectionId) {
  	foreach ($this->sectionId as $sectionId) {
  	$tags[] = "section:$sectionId";
  	}
  	}
  	return $tags;
  	}

• Element types now define the tags that should be invalidated when they are saved/deleted

  cms/src/elements/Entry.php

  Lines 839 to 852 in 8859124

  	public function getCacheTags(): array
  	{
  	$tags = [
  	"entryType:$this->typeId",
  	"section:$this->sectionId",
  	];
  	// Did the entry type just change?
  	if ($this->typeId != $this->_oldTypeId) {
  	$tags[] = "entryType:$this->_oldTypeId";
  	}
  	return $tags;
  	}

• Anything that wants to start caching things that involve element queries can do so by calling craft\services\Elements::startCollectingCacheTags() before executing the queries, and stopCollectingCacheTags() afterwards, which will return a yii\caching\TagDependency object that can be used as a cache dependency.

We’re using this new system for template caches ({% cache %} tags) and GraphQL query caches. Here’s the GraphQL code, as that’s a simpler example, since it doesn’t have to worry about nested caches like template caches do:

cms/src/services/Gql.php

Lines 417 to 440 in 8859124

	if ($cacheKey && ($cachedResult = $this->getCachedResult($cacheKey)) !== null) {
	$event->result = $cachedResult;
	} else {
	$schemaDef = $this->getSchemaDef($schema, $debugMode || StringHelper::contains($query, '__schema'));
	$elementsService = Craft::$app->getElements();
	$elementsService->startCollectingCacheTags();
	$event->result = GraphQL::executeQuery(
	$schemaDef,
	$query,
	$event->rootValue,
	$event->context,
	$event->variables,
	$event->operationName,
	null,
	$this->getValidationRules($debugMode)
	)->toArray($debugMode);
	$dep = $elementsService->stopCollectingCacheTags();
	if (empty($event->result['errors']) && $cacheKey) {
	$this->setCachedResult($cacheKey, $event->result, $dep);
	}
	}

cms/src/services/Gql.php

Lines 478 to 488 in 8859124

	public function setCachedResult(string $cacheKey, array $result, TagDependency $dependency = null)
	{
	if ($dependency === null) {
	$dependency = new TagDependency();
	}
	// Add the global graphql cache tag
	$dependency->tags[] = self::CACHE_TAG;
	Craft::$app->getCache()->set($cacheKey, $result, null, $dependency);
	}

[Mosnar]

@brandonkelly Great work! Just a heads-up, I was playing with this and if you don't create a query within the cache tag (for example, using the matched element (entry.title) instead, the cache is not automatically invalidated when the corresponding entry saves.

Does not clear on entry save:

{% cache %}
{{ entry.title }}
{% endcache %}

Does clear on entry save:

{% cache %}
    {% set entry = craft.entries.section('homepage').one() %}
    <h1>{{ entry.test }}</h1>
{% endcache %}

[brandonkelly]

@Mosnar I caught that yesterday as well. Should be fixed via decc331.