Main/Get-ExpiringCacheItem.ps1
|
<#
.SYNOPSIS Retrives a value from the local expiring cache .DESCRIPTION Retrieves either the cached value, or call the invocation definition to get a new value, which after being cached is returned to the caller .EXAMPLE PS> Get-ExpiringCacheItem -Key 'SomeKey' Retrieves the cached item for the given key, if the cache is expired the cache is updated with the new definition and returned to the caller #> function Get-ExpiringCacheItem { [CmdletBinding()] param( [Parameter(Mandatory)] [ValidateNotNullOrEmpty()] # The key to access the cached item [string] $Key = '' ) $ErrorActionPreference = 'Stop' if (-not $Script:expiringCacheObjects.Contains($Key)) { throw [xUtilityException]::New( "Get-ExpiringCacheItem", [xUtilityErrorCategory]::CacheKeyNotFound, "Item with key '$Key' was not found in the cache" ) } $cachedItem = $script:expiringCacheObjects[$Key] if ($cachedItem.Type -eq [ExpiringCacheItemType]::CustomTrigger) { $validation = . $cachedItem.CustomTrigger if ($validation -eq $true) { $cachedItem.Item = . $cachedItem.ItemDefinition $Script:expiringCacheObjects[$Key] = $cachedItem } } else { $now = Get-Date $refreshTime = $cachedItem.LastRefresh + $cachedItem.Expiration if ($refreshTime -lt $now) { # Need to refresh cache $cachedItem.Item = . $cachedItem.ItemDefinition $cachedItem.LastRefresh = $now $Script:expiringCacheObjects[$Key] = $cachedItem } } # Return cached object Write-Output $cachedItem.Item } |