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https://github.com/IISResetMe/PSCache
Generic PowerShell cache implementation
https://github.com/IISResetMe/PSCache
caching powershell
Last synced: 2 months ago
JSON representation
Generic PowerShell cache implementation
- Host: GitHub
- URL: https://github.com/IISResetMe/PSCache
- Owner: IISResetMe
- License: mit
- Created: 2017-09-24T19:15:57.000Z (over 7 years ago)
- Default Branch: development
- Last Pushed: 2021-02-11T21:56:14.000Z (almost 4 years ago)
- Last Synced: 2024-08-02T17:37:02.145Z (5 months ago)
- Topics: caching, powershell
- Language: PowerShell
- Homepage:
- Size: 41 KB
- Stars: 51
- Watchers: 7
- Forks: 1
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
Awesome Lists containing this project
- jimsghstars - IISResetMe/PSCache - Generic PowerShell cache implementation (PowerShell)
README
# PSCache
Generic PowerShell cache implementation
----
## What is PSCache?
PSCache grew out of a need to abstract away a hashtable-based "caching" scheme that I personally found myself implementing over and over again. PSCache transparently caches the results from previous queries using a custom `fetcher` - a scriptblock that'll retrieve a value from elsewhere based on a single parameter.
Here's a simple example using `PSCache` as a transparent store for results returned from `Get-ADUser`:
```powershell
Import-Module PSCache
$ADUserCache = New-PSCache -Fetcher { Get-ADUser $_ -Properties manager,title,employeeId }
# Fetch the user "jdoe" - this first cache-miss will cauce PSCache to call the `$Fetcher` scriptblock once and return the result
$ADUserCache.Get('jdoe')
# Fetch the user "jdoe" again - this time he'll be returned directly from the cache
$ADUserCache.Get('jdoe')
```
## Which eviction policies are supported?
PSCache version 0.1.1 comes with 3 optional eviction policy implementations:
### Least Recently Used (LRU)
Simple LRU policy which evicts the least recently cached entry
```powershell
# Create a cache for URL page titles
$PageTitleCache = New-PSCache { param($url) (Invoke-WebRequest $url).title } -EvictionPolicy LRU -Capacity 3
# Grab a few url page titles
$PageTitleCache.Get('https://google.com') # cache miss, cache count = 1
$PageTitleCache.Get('https://github.com') # cache miss, cache count = 2
$PageTitleCache.Get('https://google.com') # cache hit
$PageTitleCache.Get('https://stackoverflow.com') # cache miss, cache count = 3
$PageTitleCache.Get('https://bing.com') # cache miss, cache count = 3, 'https://github.com' evicted
$PageTitleCache.Get('https://github.com') # cache miss, cache count = 3, 'https://google.com' evicted
$PageTitleCache.Get('https://google.com') # cache miss, cache count = 3, 'https://stackoverflow.com' evicted
```
### Most Recently Used (MRU)
Simple MRU policy which evicts the most recently cached entry
```powershell
# Create a cache for URL page titles
$PageTitleCache = New-PSCache { param($url) (Invoke-WebRequest $url).title } -EvictionPolicy MRU -Capacity 3
# Grab a few url page titles
$PageTitleCache.Get('https://google.com') # cache miss, cache count = 1
$PageTitleCache.Get('https://github.com') # cache miss, cache count = 2
$PageTitleCache.Get('https://google.com') # cache hit
$PageTitleCache.Get('https://stackoverflow.com') # cache miss, cache count = 3
$PageTitleCache.Get('https://bing.com') # cache miss, cache count = 3, 'https://stackoverflow.com' evicted
$PageTitleCache.Get('https://github.com') # cache hit
$PageTitleCache.Get('https://google.com') # cache hit
```
### Least Frequently Used (LFU)
Simple LFU policy which evicts the least recently cached entry of those least frequently used
```powershell
# Create a cache for URL page titles
$PageTitleCache = New-PSCache { param($url) (Invoke-WebRequest $url).title } -EvictionPolicy LFU -Capacity 3
# Grab a few url page titles
$PageTitleCache.Get('https://google.com') # cache miss, cache count = 1
$PageTitleCache.Get('https://github.com') # cache miss, cache count = 2
$PageTitleCache.Get('https://google.com') # cache hit
$PageTitleCache.Get('https://stackoverflow.com') # cache miss, cache count = 3
$PageTitleCache.Get('https://bing.com') # cache miss, cache count = 3, 'https://stackoverflow.com' evicted
$PageTitleCache.Get('https://github.com') # cache miss, cache count = 3, 'https://bing.com' evicted
$PageTitleCache.Get('https://google.com') # cache hit
```
## Roadmap
PSCache is currently very basic. Future plans include both time- and counter-based eviction policies (globally and per-key), as well as explicit cache size settings.