Cache

Server-level caching mechanism in PowerShell Universal.

PowerShell Universal provides the ability to use a server-level cache to store data that you use between APIs, Automation and Dashboards. You can configure cache item life times use the Set-PSUCache cmdlet in any PowerShell script you run in PowerShell Universal. You can also retrieve items from the cache using Get-PSUCache.

Some examples of usages for the cache may be:

• Collecting data with a scheduled job and displaying it within a dashboard

• Collecting data from an API and using it in a job

• Collecting using input from a dashboard and queuing it to run in a scheduled job

Setting items in the cache

To set items in the cache, you can use Set-PSUCache. Items in the cache are serialized to strings using CLIXML and the PowerShell serializer. When you retrieve objects from the cache, they will no longer be live objects.

Set-PSUCache -Key "CurrentDate" -Value (Get-Date)

There are three types of cache invalidation techniques you can employ.

Absolute Expiration

The AbsoluteExpiration parameter defines at what time the item in the cache is invalidated.

The follow example invalidates the cache item after 10 minutes.

Set-PSUCache -Key "CurrentDate" -Value (Get-Date) -AbsoluteExpiration (Get-Date).AddMinutes(10)

Absolute Expiration From Now

The AbsoluteExpirationFromNow parameter defines when a cache item is invalidated using a TimeSpan rather than a calculated DateTime.

The following cache item is invalidated 1 hour from now.

Set-PSUCache -Key "CurrentDate" -Value (Get-Date) -AbsoluteExpirationFromNow ([TimeSpan]::FromHours(1))

Sliding Expiration

The SlidingExpiration parameter allows you to defines the amount of time before the cache item is invalidated. Each time the cache item is accessed, the timer is reset.

The following cache item will be invalidated in 5 minutes. If it's accessed within those 5 minutes, it will be reset for another 5 minutes.

Set-PSUCache -Key "CurrentDate" -Value (Get-Date) -SlidingExpiration ([TimeSpan]::FromMinutes(5))

Getting items from the cache

You can use the Get-PSUCache cmdlet to retrieve items from the cache. You simply need to supply the key of the item you wish to retrieve. The deserialized object will be returned from the cmdlet.

Get-PSUCache -Key "CurrentDate"

API

Get-PSUCache

Returns data from the cache.

Name	Type	Description	Required
Key	string	The key to the data stored in the cache.	True

Set-PSUCache

Sets data into the cache.

Name	Type	Description	Required
Key	string	The key for the data stored in the cache.	True
Value	string	The data to be stored in the cache. It will be stored as CliXml.	True
AbsoluteExpiration	DateTime	The date and time of the expiration of this data. It will be removed from the cache at this time.	False
AbsoluteExpirationFromNow	TimeSpan	A length of time to keep the data within the cache. It will be removed after that amount of time.	False
SlidingExpiration	TimeSpan	A length of time to keep the data within the cache. Each time the data is accessed, the time is reset. If the data isn't accessed during the expiration time, it will be removed from the cache.	False