Configure Advanced Cache Key for an application

Vary a cached object by a query string argument or by a cookie, then apply the cache setting to an application with a Rules Engine rule.

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Application Accelerator unlocks Advanced Cache Key, which varies a cached object by query string argument or by cookie. You configure it in a cache setting from Azion Console, then apply that cache setting with Rules Engine.

For content that does not vary between requests, refer to Configure cache policies. For what a variation changes in the cache key, refer to Cache variation.

Prerequisites

Turn on Application Accelerator

The module is off by default, and a cache setting varies the cached object only while the module is on. To turn it on:

Open the application

Access Azion Console > Applications > your application.

Turn on the module

On the Main Settings tab, in the Modules section, turn on Application Accelerator.

Select Save

The application runs with Application Accelerator, and its cache settings can vary the cached object by query string or cookie.

Vary the cache by a query string argument

An application serves the URL domain.com/page?city=city_name. The /page URI calls an API that lists content for the city in the city argument. The API refreshes that content every five minutes. To store one object per city, and to expire it at the same interval:

Open the Cache Settings tab

Access Azion Console > Applications > your application, then go to the Cache Settings tab.

Select + Cache
Name the cache setting

In Name, enter a name that identifies the setting. For example: city-listing.

Set the browser cache

Under Browser Cache, select Override cache settings and set the maximum age to 300.

Set Max Age

Under Cache, select Override cache behavior and set Max Age to 300.

Allowlist the argument

Under Application Accelerator, open Cache vary by Query String and set Behavior to Allowlist.

Enter the argument

Add city to the list of query string arguments.

Select Save

The cache setting appears in the Cache Settings tab, and it varies the cached object by the city argument.

Cache keys are case sensitive. Azion stores ?city=Lisbon and ?city=lisbon as two objects.

A cache setting takes effect only when a rule applies it. To apply this one to the /page URI:

Go to the Rules Engine tab
Select + Rule
Name the rule

Enter a name for the rule. For example: city-listing rule.

Select Request Phase
Select the variable in the Criteria section

In the Criteria section, select the ${uri} variable.

Select starts with as the comparison operator
Enter the argument

Enter /page as the argument.

In the Behaviors section, select Set Cache Policy
Select the cache setting you created
Select Save

Requests whose URI starts with /page carry the cache setting. The browser and Azion hold each city object for 300 seconds. A new rule takes a few minutes to propagate.

An application authenticates users with a cookie, and the /profile page it serves after a login must differ per session. The cookie session_cookie carries the value that identifies the session. To store one object per session:

Open the Cache Settings tab

Access Azion Console > Applications > your application, then go to the Cache Settings tab.

Select + Cache
Name the cache setting

In Name, enter a name that identifies the setting. For example: profile-by-session.

Set the cache behavior

In the Browser Cache and Cache sections, set the behavior and the age the profile page needs.

Allowlist the cookie

Under Application Accelerator, open Cache vary by Cookies and set Behavior to Allowlist.

Enter the cookie name

Add session_cookie to the list of cookie names.

Select Save

The cache setting appears in the Cache Settings tab, and it varies the cached object by the value of session_cookie. Cookie names are case sensitive, like every value that composes a cache key.

To apply this cache setting to the /profile URI:

Go to the Rules Engine tab
Select + Rule
Name the rule

Enter a name for the rule. For example: profile rule.

Select Request Phase
Select the variable in the Criteria section

In the Criteria section, select the ${uri} variable.

Select starts with as the comparison operator
Enter the argument

Enter /profile as the argument.

In the Behaviors section, select Set Cache Policy
Select the cache setting you created
Select Save

Requests whose URI starts with /profile carry the cache setting. Each session receives the object cached for its own session_cookie value. A new rule takes a few minutes to propagate.

Next steps

Cache variationWhat a variation changes in the cache key, and what it costs you in stored objects.Application Accelerator settingsEvery field the module adds to a cache setting, with its values and defaults.Real-Time PurgeExpire an object that varies, which a URL purge does not always reach.Verify cache indicators with ModHeaderRead the cache headers a request returns and confirm the variation you configured.Optimize images for websites and mobile appsA cache setting that varies by the ims argument, so each image size is cached once.