Cache

You can see cache information directly in your Cockpit in the Content delivery section. You can configure what items are cached.

To configure what to cache, you need to update the configuration in your Magnolia instance and not directly via the CDN.

Typically, you would find this at:

/modules/cache/config/contentCaching/defaultPageCache/browserCachePolicy/policies/resources

configure cache resources

Default cached items

By default, CSS, JavaScript, and images are cached. Pages are not cached by default. However, you can configure your policy to cache Pages.

See Server cache policy for help with that.

Configuration

Cache configuration is defined in /modules/cache/config/contentCaching/. Within each configuration you can define:

  • What to cache.

  • When to flush the cache.

  • What header data to pass to browsers.

  • Specific implementations of tasks.

Node name Value

πŸ“ modules

     πŸ“ cache

         πŸ“ config

             πŸ“ contentCaching

                 βΈ¬ defaultPageCache

                 βΈ¬ uuid-key-mapping

             βΈ¬ compression

             βΈ¬ cacheFactory

             ⬩ cacheResponseThreshold

1000

The default value for cacheResponseThreshold is 500. For more information and configuration details, see the [_cache_threshold] subsection below.

To select one of the cache configurations, set the defaultContentCachingConfigurationName parameter in the Cache filter. The chosen configuration is read into a JavaBean using the Node2Bean mechanism, making it dynamically available to your own module code.

Node name Value

πŸ“ server

     πŸ“ filters

         πŸ“ cache

             ⬩ defaultContentCachingConfigurationName

defaultPageCache

             ⬩ class

info.magnolia.module.cache.filter.CacheFilter

Policy configuration

Caching behavior for each configuration is defined with policies.

Server cache policy

This policy defines whether the requested content should be cached or not. The decision to cache relies on voters, which are used whenever configuration values aren’t assigned at startup but depend on rules.

Voters evaluate a rule such as should content residing at this URL be cached and return a positive or negative response. By default, all content on public instances is cached except the AdminCentral UI at /.magnolia. Server cache policy is configured in /modules/cache/config/contentCaching/defaultPageCache/cachePolicy.

The default implementation (info.magnolia.module.cache.cachepolicy.Default) checks if the content exists in the cache store and requests caching if the content is not found. The alternative class (info.magnolia.module.cache.cachepolicy.Never) instructs the cache not to store the generated content. Server-side re-caching of no-cache requests (shift reload) is configurable and set to false by default.

Node name Value

βΈ¬ defaultPageCache

     βΈ¬ cachePolicy

         βΈ¬ shouldBypassVoters

             βΈ¬ urls

             βΈ¬ deny

                 βΈ¬ parameters

                     βΈ¬ whitelist

                         ⬩ 0

^utm_.*$

             βΈ¬ resources

             ⬩ class

info.magnolia.module.cache.cachepolicy.Default

             ⬩ refreshOnNoCacheRequests

false

Whitelisting specific parameters

Since Magnolia 6.2.30, under ../shouldBypassVoters/deny/parameters/whitelist, you can configure a key-value(regex) map of request parameters that should be ignored and hence their requests cached as a result.

As shown in the example above, the map configured there causes caching of all requests containing the utm_* tracking tag(s), which could otherwise generate a high server load, for example when sending marketing mails or other material utilizing the utm_* tracking tag(s).

Cache key generator

You can define a custom cache key generator or configure the default one to meet your needs.

πŸ“ cache

     πŸ“ config

         πŸ“ contentCaching

             βΈ¬ defaultPageCache

                 βΈ¬ cachePolicy

                     βΈ¬ shouldBypassVoters

                     βΈ¬ ttlVoters

                     βΈ¬ cacheKeyGenerator

                         ⬩ useRequestParameters

false

                         ⬩ class

info.magnolia.module.cache.cachekey.DefaultCacheKeyGenerator

                     ⬩ class

info.magnolia.module.cache.cachepolicy.Default

Attribute Default Description

useUri

true

Use URI as part of cache key.

useRequestParameters

true

Use request query as part of cache key.

useRequestMethod

true

Use request method (GET/POST/HEAD) as part of cache key.

useRequestServerName

true

Use server name as part of cache key.

useRequestGetSecure

true

Save information whether this request was made using a secure channel, such as HTTPS as part of cache key.

useUserName

true

Use user name as part of cache key.

useLocale

true

Use locale info.magnolia.cms.core.AggregationState#getLocale as part of cache key.

useChannel

true

Use channel info.magnolia.cms.core.AggregationState#getChannel as part of cache key.

Client (browser) cache policy

Allows for different policies for different content types. Voters are used to define the caching rules.

These policies define how long the browser may cache each content type. The time is passed to the browser in the response header.

  • info.magnolia.module.cache.browsercachepolicy.FixedDuration instructs the browser to cache the content for the specified length of time in minutes.

  • info.magnolia.module.cache.browsercachepolicy.Never instructs the browser to do nothing.

Client cache policy is configured in /modules/cache/config/contentCaching/defaultPageCache/browserCachePolicy.
Cache-Control directives

Using the directives property, you can also specify standard Cache-Control directives.

The directives property is only applied to info.magnolia.module.cache.browsercachepolicy.FixedDuration.

This is where we define cache headers. Fastly processes these defined headers. You can also set certain headers so that it affects only Fastly and not the browser cache.

See Fastly’s docs for more on controlling cache.

Example configuration

Node name Value

βΈ¬ defaultPageCache

     βΈ¬ browserCachePolicy

         βΈ¬ policies

             βΈ¬ disableBrowserCacheInDevelopMode

                 βΈ¬ voters

                     βΈ¬ developMode

                         ⬩ class

info.magnolia.voting.voters.PropertyVoter

                         ⬩ property

magnolia.develop

                         ⬩ value

true

                 ⬩ class

info.magnolia.module.cache.browsercachepolicy.FixedDuration

             βΈ¬ farFuture

                 ⬩ class

info.magnolia.module.cache.browsercachepolicy.FixedDuration

                 ⬩ expirationMinutes

525600

                 βΈ¬ voters

             βΈ¬ resources

                 ⬩ class

info.magnolia.module.cache.browsercachepolicy.FixedDuration

                 ⬩ expirationMinutes

60

                 βΈ¬ voters

                     ⬩ op

OR

                     βΈ¬ dotResources

                         ⬩ class

info.magnolia.voting.voters.URIStartsWithVoter

                         ⬩ pattern

/.resources/

                     βΈ¬ contentType

                         ⬩ class

info.magnolia.voting.voters.RequestExtensionVoter

                         ⬩ emptyExtensionVote

false

                         βΈ¬ allowed

                             ⬩ css

css

                             ⬩ js

js

             βΈ¬ dontCachePages

                 ⬩ class

info.magnolia.module.cache.browsercachepolicy.Never

                 βΈ¬ voters

             βΈ¬ default

                 ⬩ class

info.magnolia.module.cache.browsercachepolicy.FixedDuration

                 ⬩ directives

public, max-age=604800, immutable

                 ⬩ expirationMinutes

10

         ⬩ class

info.magnolia.module.cache.browsercachepolicy.BrowserCachePolicySet

Since Magnolia 6.2.34, the emptyExtensionVote property can control the behavior of the RequestExtensionVoter class in case the request URL has no extension. The default value is true.

Flush policy

The flush policy defines when to flush the cache. There are three policies, two of which are installed by default.

Flush upon changes from content publication

The default policy is info.magnolia.module.cache.flushpolicy.FlushAllFromPublishingEventPolicy, and you can set it via /modules/cache/config/contentCaching/defaultPageCache/flushPolicy/policies/flushAll@class.

This configuration flushes the cache whenever a publishing event is completely finished.

The cache can only be flushed completely. Each module can register its own flush policy (or multiple policies) and receive events in each workspace. Flush policies are informed about notifications from the publication module. By default, all workspaces are allowed to flush unless they’re listed under the excludedWorkspaces subnode. Alternatively, you can list the allowed workspaces per policy under the workspaces subnode of each policy.

Flush upon changes in workspaces

This configuration observes changes (content publication, import, edit) in a workspace and flushes the cache if new or modified content is detected.

The cache can be flushed completely, partially or not at all. Each module can register its own flush policy (or multiple policies) and receive notifications about new or modified content in each workspace. Flush policies are informed about changes in observed workspaces. By default, all workspaces trigger a cache flush unless they’re listed under the excludedWorkspaces subnode.

Performance aspects

To improve performance, list the observed workspaces per policy under the workspaces subnode of each policy.

If your custom workspace doesn’t affect the content of pages, you should register it under excludedWorkspaces, otherwise, a change in that workspace unnecessarily flushes the cache.

To enable this configuration, set /modules/cache/config/contentCaching/defaultPageCache/flushPolicy/policies/flushAll@class to info.magnolia.module.cache.FlushAllListeningPolicy.

Flush upon changes in light modules

Magnolia 5.6.1+: A change in the light modules folder may also flush the server cache. See /modules/cache/config/contentCaching/defaultPageCache/flushPolicy/policies/lightModule/pathToCacheMappings/defaultPageCache with the pattern property, which specifies the pattern for the operation. The default value is ./(templates|webresources|i18n)/..

Node name Value

βΈ¬ defaultPageCache

     βΈ¬ flushPolicy

         βΈ¬ policies

             βΈ¬ flushAll

                 βΈ¬ excludedWorkspaces

                     ⬩ forum

forum

                     ⬩ imaging

imaging

                     ⬩ magnolia-mgnlSystem

magnolia-mgnlSystem

                     ⬩ magnolia-mgnlVersion

magnolia-mgnlVersion

                     ⬩ messages

messages

                     ⬩ profiles

profiles

                     ⬩ users

users

                 ⬩ class

info.magnolia.module.cache.FlushAllListeningPolicy

             βΈ¬ lightModules

                 βΈ¬ defaultPageCache

                     ⬩ cacheName

defaultPageCache

                     ⬩ pattern

.*/(templates

webresources

i18n)/.*

                 ⬩ class

info.magnolia.module.cache.flushpolicy.LightModuleChangesFlushPolicy

         ⬩ class

info.magnolia.module.cache.DelegateFlushPolicy

Executors

These are actions taken once a caching decision is made. There are three possible actions:

  1. useCache: Retrieves the cached item from the cache and streams it to the client.

  2. store: Stores the response in the cache for future use.

  3. bypass: Skips caching. This is useful for content that can’t or shouldn’t be cached.

Executors can be configured at /modules/cache/config/contentCaching/defaultPageCache/executors. Each of the executors is also responsible for configuring expiration headers.
Node name Value

βΈ¬ defaultPageCache

     βΈ¬ executors

         βΈ¬ bypass

         βΈ¬ store

         βΈ¬ useCache

Cacheable response codes

By default, all cacheable response codes are cached. For a full list, see RFC-7231: Overview of Status Codes and RFC 7233: 206 Partial Content.

Using the cacheableResponseCodes property, you can define exactly which codes you want cached.

...
defaultPageCache:
  executors:
    store:
      cacheContent:
        cacheableResponseCodes: 200,300,400 (1)
...
1 Where 200, 300, and 400 are cached only.
Response headers in redirect requests

Setting cacheHeadersInRedirects to true allows headers to be included in the response of the redirect request (302).

...
defaultPageCache:
  executors:
    store:
      cacheContent:
        cacheHeadersInRedirects: true (1)
...
1 By default, the property is set to false to keep the behavior consistent with the previous versions.
Whitelisting headers to be included in a cache key

Under allowedRequestHeaders, you can list headers that can be included in a cache key.

...
defaultPageCache:
  cachePolicy:
    cacheKeyGenerator:
      allowedRequestHeaders:
        x-my-header: x-my-header (1)
...
1 The x-my-header is allowed in this example, but the list is empty by default.

Compression

Compression is a simple and effective way to save bandwidth and speed up your site. It’s a common practice used by Google and Yahoo! for example. (How to Optimize Your Site with GZIP Compression is a great general introduction to the topic).

Compression is performed in the gzip filter, configured in /server/filters/gzip}. When a client requests a resource such as index.html, Magnolia delivers it zipped. A typical HTML page is compressed to 20% of its original size. So if your page is 100 kB uncompressed, it’s 20 kB compressed. To improve performance further, zipped content is streamed from the repository to the client rather than read into memory first.

Configuring

You can configure which content types to compress. By default, the gzip filter bypasses compression for HTML, JavaScript and CSS because they’re explicitly selected for compression in the Cache module configuration. These types can be compressed efficiently because they’re text. The decision to compress a particular content type is made with voters. Voters are used whenever configuration values aren’t assigned at startup but depend on rules instead. In the Cache module configuration there are three voting rules based on content type:

  • text/html: HTML.

  • application/x-javascript: JavaScript.

  • text/css: Cascading Style Sheets.

Node name Value

πŸ“ cache

     πŸ“ config

         βΈ¬ compression

             βΈ¬ voters

                 βΈ¬ contentType

                     βΈ¬ allowed

                         ⬩ 1

text/html

                         ⬩ 2

application/x-javascript

                         ⬩ 3

text/css

                     ⬩ class

info.magnolia.voting.voters.RequestExtensionVoter

To add more content types, such as XML, create a numbered property under allowed. Use the Internet media type (MIME type) as value. Here are some common media types:

  • application/xhtml-xml: XHTML.

  • text/csv: Comma-separated value.

  • text/plain: Textual data.

  • text/xml: Extensible Markup Language.

  • application/pdf: Portable Document Format.

As a rule, compressing the HTML, JavaScript and CSS is sufficient; it’s not necessary to compress binary content such as images. During the process, the browser sends a header telling the server that it accepts compressed content: Accept-Encoding: gzip. Note that Magnolia doesn’t cache big binaries.

Testing compression

To test your compression configuration, use a tool such as Web-Sniffer that allows you to change the Accept, Encoding and User-Agent sent headers easily. Here’s what the headers look like when the Magnolia demo site home page is submitted^ to the sniffer.

Request header
GET /demo-project.html HTTP/1.1 Host: demopublic.magnolia-cms.com
Connection: close User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1;
de; rv:1.9) Gecko/2008052906 Firefox/3.0 Accept-Encoding: gzip
Accept-Charset: ISO-8859-1,UTF-8;q=0.7,*;q=0.7 Cache-Control: no
Accept-Language: de,en;q=0.7,en-us;q=0.3 Referer: http://web-sniffer.net
Response header
Status: HTTP/1.1 200 OK Date: Fri, 23 Jul 2010 07:45:10 GMT Server:
Apache/2.2.9 X-Magnolia-Registration: Registered Cache-Control:
max-age=900 Last-Modified: Thu, 01 Jul 2010 14:03:12 GMT
Content-Encoding: gzip Vary: Accept-Encoding Content-Length: 3852
Connection: close Content-Type: text/html;charset=UTF-8
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