Caching

Caching rendered content in Fusion

#Introduction

The frontend rendering of a document node in Neos can involve many queries and operations. Doing this for every request would be too slow to achieve a feasible response time. The content cache is a feature of Fusion and supports a configurable and nested cache that can answer many requests directly from the cache without expensive operations. It is based on the Flow caching framework that supports many different cache backends, expiration and tagging.

Each Fusion path (of type object) can have its own cache configuration. These cache configurations can be nested to re-use parts of the content and have multiple cache entries with different properties on the same page. This could be a menu or section that is the same for many pages. The nesting support is also allows to have uncached content like plugins inside cached content.

The content cache is active even when you are in editing mode. Cache entries will be flushed automatically whenever data has changed through a tag based strategy or when relevant files changed during development (code, templates or configuration).

Note

In Neos, you don’t a have a button to clear the cache. Cache invalidation is handled by the core and can be configured to be application specific. It’s really important to configure the cache correctly to avoid problems with cache invalidation.

*An example cache hierarchy with different modes*

Let’s see how the content cache can help you to deliver a faster user experience.

#The basics

The main Fusion path is root, you can find it in the file Fusion/DefaultFusion.fusion in theNeos.Neos package. Here is a small part of this file that shows the outermost cache configuration of the root path:

root = Neos.Fusion:Case {
	default {
		@position = 'end 9999'
		condition = TRUE
		renderPath = '/page'
	}

	@cache {
		mode = 'cached'
		entryIdentifier {
			node = ${node}
		}
		entryTags {
			# Whenever the node changes the matched condition could change
		  	1 = ${Neos.Caching.nodeTag(documentNode)}
		  	# Whenever one of the parent nodes changes the layout could change
		  	2 = ${Neos.Caching.nodeTag(q(documentNode).parents())}
		}
	}
}

The given configuration will cache the entire page content with a unique identifier defined by the current node (the document node), the preview mode and globally configured entry identifiers.

Note

All entryIdentifier values will be evaluated and combined to a single string value (the keys will be part of the identifier and sorted alphabetically).

In the @cache meta property the following subproperties are allowed:

mode
Sets the caching mode of the current path. Possible values are 'embed' (default), 'cached','dynamic' or 'uncached'. Only simple string values are supported for this property.

It defaults to mode embed which will not create a new cache entry but store the content into the next outer cached entry. With mode cached a separate cache entry will be created for the path. Mode uncached can be used to always evaluate a path even if is contained inside a cached path. The dynamic mode evalutes a so called “discriminator” on every request and caches results differently depending on it’s value. Dynamic cache mode is therefore much faster than uncached but slightly slower compared to cached mode. It is useful in situations where arguments (eg. from the request) lead to different rendering results. The context property should be set to configure the Fusion context variables that will be available when evaluating the uncached path.
maximumLifetime
Set the maximum lifetime for the nearest cached path. Possible values are null (default), 0(unlimited lifetime) or the amount of seconds as an integer.

If this property is declared on a path with caching mode cached or dynamic it will set the lifetime of the cache entry to the minimum of all nested maximumLifetime configurations (in paths with mode embed) and the maximumLifetime of the current configuration.
entryIdentifier
Configure the cache entry identifier for mode cached or dynamic based on an array of values.

The prototype Neos.Fusion:GlobalCacheIdentifiers will be used as the base object, so global values that influence all cache entries can be added to that prototype, see Global cache entry identifiers for more details.

If this property is not set, the identifier is built from all Fusion context values that are simple values or implement CacheAwareInterface.

The identifier string value will be a hash built over all array values including and sorted by their key.

Note

It is very important to add all values that influence the output of the current path to the entryIdentifier array since cache entries will be re-used across rendered documents if the same identifier is requested. In the cache hierarchy the outermost cache entry determines all the nested entries, so it’s important to add values that influence the rendering for every cached path along the hierarchy.

entryTags
Configure a set of tags that will be assigned to the cache entry for mode cached or dynamic as an array.

The correct entry tags are important to achieve an automatic flushing of affected cache entries if a node or other data in Neos was changed during editing, publishing or other actions. A number of tags with a specific pattern are flushed by default in Neos whenever a node is changed, published or discarded. See Cache Entry Tags for a full list.
context
Configure a list of variable names that will be stored from the Fusion context for later rendering of a path with mode uncached or dynamic. Only values that are configured here will be available in Fusion when the path is evaluated in subsequent request.

Example from Plugin.fusion:

prototype(Neos.Neos:Plugin) {
        @cache {
                mode = 'uncached'
                context {
                        1 = 'node'
                        2 = 'documentNode'
                }
        }
}

entryDiscriminator
Configure an expression that uniquely discriminates different entries of a dynamic cached area. The expression or Fusion object must evaluate to a string to be used as discriminator and should be different for every cache entry you want to create for this dynamic cached area.

Example for a dynamic configuration with entryDiscriminator:

prototype(Neos.Neos:Plugin) {
        @cache {
                mode = 'dynamic'
                entryIdentifier {
                  node = ${node}
                }
                entryDiscriminator = ${request.arguments.pagination}
                context {
                        1 = 'node'
                        2 = 'documentNode'
                }
                entryTags {
                        1 = ${Neos.Caching.nodeTag(node)}
                }
        }
}

When using dynamic as the cache mode, the cache can be disabled by setting the entryDiscriminator to false. This can be used to make the cache behavior dependable on some context, i.e. the current request method:

prototype(Neos.NodeTypes:Form) {
        @cache {
                mode = 'dynamic'
                entryIdentifier {
                  node = ${node}
                }
                entryDiscriminator = ${request.httpRequest.method != 'POST' ? 'static' : false}
                context {
                        1 = 'node'
                        2 = 'documentNode'
                }
        }
}

In this example the Form will be cached unless the request method is POST in which case it is switched to uncached.

#Cache Entry Tags

Neos will automatically flush a set of tags whenever nodes are created, changed, published or discarded. The exact set of tags depends on the node hierarchy and node type of the changed node. You should assign tags that matches one of these patterns in your configuration. You can use an Eel expression to build the pattern depending on any context variable including the node identifier or type.

To create the correct tags for your node it is important to make use of our CachingHelper. The following methods are provided by default to create all kind of patterns of tags wich will be flushed by Neos:

Everything
Flushes cache entries for every changed node.
${Neos.Caching.nodeTypeTag('My.Package:NodeTypeName', node)}
Flushes cache entries if any node with the given node type changes. My.Package:NodeTypeName needs to be replaced by any node type name. Inheritance will be taken into account, so for a changed node of type Neos.NodeTypes:Page the tags NodeType_Neos.NodeTypes:Page and NodeType_Neos.Neos:Document (and some more) will be flushed. The second property node is needed to calculate the correct context to create tags for. Notice: In earlier versions of Neos we just used a plain String NodeType_[My.Package:NodeTypeName] which could lead into unwanted cache flush behaviors
${Neos.Caching.nodeTag(node)}
Flushes cache entries if the node changes. Notice: In earlier versions of Neos we just used a plain String Node_[Identifier] which could lead into unwanted cache flush behaviors. Identifier had to be replaced by a valid node identifier. You might want to use${Neos.Caching.nodeTagForIdentifier("identifier")} if you don’t have a node instance but only a node identifier as string.
${Neos.Caching.descendantOfTag(node)}
Flushes cache entries if a child node of the node changes. Notice: In earlier versions of Neos we just used a plain String DescendantOf_[Identifier] which could lead into unwanted cache flush behaviors. Identifier had to be replaced by a valid node identifier.

Example:

prototype(Neos.Neos:ContentCollection) {
	#...

	@cache {
		#...
		mode = 'cached'
		entryIdentifier {
		  	collection = ${node}
		}
		entryTags {
			# A cache entry with this tag will be flushed
			# whenever one of the given nodes (for any variant) is updated.
			1 = ${Neos.Caching.nodeTag(node)}
			# A cache entry with this tag will be flushed
			# whenever a node (for any variant) that is a descendant (child on any level)
			# of one of the given nodes is updated.
			2 = ${Neos.Caching.descendantOfTag(node)}
		}
	}
}

The ContentCollection cache configuration declares tags that will flush the cache entry for the collection if any of it’s descendants (direct or indirect child) changes. So editing a node inside the collection will flush the whole collection cache entry and cause it to re-render.

Note

When using cached as the cache mode, your entryTags should always contain the node identifier. Otherwise, the cache will not be flushed when you make changes to the node itself, which will lead to unexpected behavior in the Neos backend:

@cache {
       mode = 'cached'
       entryTags {
               1 = ${Neos.Caching.nodeTag(node)}
               2 = ... additional entry tags ...
       }
}

Notice: In earlier versions of Neos there might be some problems with unwanted cache flush behaviours. To make sure
to avoid this always use the CachingEelHelper. See https://github.com/neos/neos-development-collection/issues/2096
for more informations

#Default cache configuration

The following list of Fusion prototypes is cached by default:

Neos.Neos:Breadcrumb
Neos.Neos:Menu
Neos.Neos:Page
Neos.Neos:ContentCollection (see note)

The following list of Fusion prototypes is uncached by default:

Neos.NodeTypes:Form
Neos.Neos:Plugin

Note

The Neos.Neos:ContentCollection prototype is cached by default and has a cache configuration with proper identifier, tags and maximumLifetime defined. For all ContentCollection objects inside a Content object the mode is set to embed. This means that node types that have a ContentCollection do not generate a separate cache entry but are embedded in the outer static ContentCollection.

#Overriding default cache configuration

You can override default cache configuration in your Fusion:

prototype(Neos.Neos:PrimaryContent).@cache.mode = 'uncached'

You can also override cache configuration for a specific Fusion Path:

page.body.content.main {
    prototype(Neos.Neos:Plugin).@cache.mode = 'cached'
}

#Global cache entry identifiers

Information like the request format or base URI that was used to render a site might have impact on all generated URIs. Depending on the site or application other data might influence the uniqueness of cache entries. If an entryIdentifier for a cached path is declared without an object type, it will default to Neos.Fusion:GlobalCacheIdentifiers:

prototype(My.Package:ExampleNode) {
        @cache {
                mode = 'cached'

                # This is the default if no object type is specified
                # entryIdentifier = Neos.Fusion:GlobalCacheIdentifiers
                entryIdentifier {
                        someValue = ${q(node).property('someValue')}
                }
        }
}

This prototype can be extended to add or remove custom global values that influence all cache entries without a specific object type:

prototype(Neos.Fusion:GlobalCacheIdentifiers) {
        myRequestArgument = ${request.arguments.myArgument}
}

You can use a Neos.Fusion:RawArray to explicitly specify the values that are used for the entry identifier:

prototype(My.Package:ExampleNode) {
        @cache {
                mode = 'cached'

                entryIdentifier = Neos.Fusion:RawArray {
                        someValue = ${q(node).property('someValue')}
                }
        }
}

#Security Context

In addition to entry identifiers configured in Fusion, the Security Context Hash is added to the identifier of all cached segments. This hash is build from the roles of all authenticated accounts and cache identifiers from custom global objects (exposed through Neos.Flow.aop.globalObjects) implementing CacheAwareInterface.

Custom Global Objects are explained in detail in the Flow documentation: http://flowframework.readthedocs.io/en/stable/TheDefinitiveGuide/PartIII/Security.html#content-security-entityprivilege.

#Tuning your cache

#Change the cache backend

By default, all cache entries are stored on the local filesystem. You can change this in Caches.yaml, the example below will use the Redis backend for the content cache:

Neos_Fusion_Content:
  backend: Neos\Cache\Backend\RedisBackend

Note

The best practice is to change the cache configuration in your distribution.

Caching

#Introduction

#The basics

#Cache Entry Tags

#Default cache configuration

#Overriding default cache configuration

#Global cache entry identifiers

#Security Context

#Tuning your cache

#Change the cache backend

#Further reading