✨ Get-CachedCommand.ps1 & Get-PathUsage.ps1

- resolves brianary#61

Author: brianary

Get-CachedCommand.ps1

@@ -0,0 +1,105 @@
+<#
+.SYNOPSIS
+Caches the output of a command for recall if called again.
+
+.FUNCTIONALITY
+Command
+
+.EXAMPLE
+Get-CachedCommand.ps1 {Invoke-RestMethod https://example.org/endpoint} -Session
+
+Returns the result of executing the script block, or the previous cached output if available.
+#>
+
+#Requires -Version 7
+[CmdletBinding()] Param(
+# Specifies the expression to cache the output of.
+[Parameter(Position=0,Mandatory=$true)][scriptblock] $Expression,
+# Parameters to the script block.
+[Parameter(Position=1,ValueFromRemainingArguments=$true)][psobject[]] $BlockArgs = @(),
+# The rolling duration to cache the output for (updated with each call).
+[Parameter(ParameterSetName='ExpiresAfter')][timespan] $ExpiresAfter,
+# Point in time to cache the output until.
+[Parameter(ParameterSetName='Expires')][datetime] $Expires,
+# Caches the output for this session.
+[Parameter(ParameterSetName='Session')][switch] $Session
+)
+Begin
+{
+    $Script:Hash = [Security.Cryptography.MD5]::Create()
+    function Get-ScriptBlockHash
+    {
+        [CmdletBinding()] Param(
+        [Parameter(Position=0)][scriptblock] $ScriptBlock,
+        [Parameter(Position=1)][psobject[]] $BlockArgs = @()
+        )
+        return (@("$ScriptBlock") + @($BlockArgs |ForEach-Object {ConvertTo-Json $_ -Compress}) |
+            ForEach-Object {ConvertTo-Base64.ps1 $Script:Hash.ComputeHash([Text.Encoding]::UTF8.GetBytes($_)) -UriStyle}) -join '.'
+    }
+
+    $Script:SessionCacheName = "$(Split-Path $PSCommandPath -LeafBase)#$PID"
+    $Script:SessionCache = Get-Variable $Script:SessionCacheName -Scope Global -ErrorAction Ignore
+    if(!$Script:SessionCache)
+    {
+        $Script:SessionCache = Set-Variable $Script:SessionCacheName @{} -Scope Global -Option Constant -PassThru `
+            -Description 'Cached command output'
+    }
+    $Script:CacheDir = if($IsWindows)
+    {
+        Join-Path $env:LocalAppData (Split-Path $PSCommandPath -LeafBase)
+    }
+    elseif($IsLinux)
+    {
+        Join-Path ($env:XDG_CACHE_HOME ?? "$HOME/.cache") (Split-Path $PSCommandPath -LeafBase)
+    }
+    else
+    {
+        Join-Path $env:TEMP (Split-Path $PSCommandPath -LeafBase)
+    }
+    New-Item $Script:CacheDir -Type Directory -ErrorAction Ignore |Out-Null
+    Get-ChildItem $Script:CacheDir |
+        Where-Object LastWriteTime -lt (Get-Date) |
+        Remove-Item
+    function Get-CachedOutput
+    {
+        [CmdletBinding()] Param(
+        [Parameter(Position=0)][scriptblock] $ScriptBlock,
+        [Parameter(Position=1)][psobject[]] $BlockArgs = @(),
+        [datetime] $Expires
+        )
+        $now = Get-Date
+        $cacheFileName = Join-Path $Script:CacheDir "$(Get-ScriptBlockHash $ScriptBlock).xml"
+        if(Test-Path $cacheFileName -Type Leaf)
+        {
+            $cacheFile = Get-Item $cacheFileName
+            if($now -gt $cacheFile.LastWriteTime)
+            {
+                $ScriptBlock.InvokeReturnAsIs($BlockArgs) |Export-Clixml $cacheFileName -Force
+            }
+        }
+        else
+        {
+            $ScriptBlock.InvokeReturnAsIs($BlockArgs) |Export-Clixml $cacheFileName
+            $cacheFile = Get-Item $cacheFileName
+        }
+        $cacheFile.LastWriteTime = $now
+        Import-Clixml $cacheFileName
+    }
+}
+Process
+{
+    switch($PSCmdlet.ParameterSetName)
+    {
+        ExpiresAfter {Get-CachedOutput $Expression -BlockArgs $BlockArgs -Expires (Get-Date).Add($ExpiresAfter)}
+        ExpiresAfter {Get-CachedOutput $Expression -BlockArgs $BlockArgs -Expires $Expires}
+        Session
+        {
+            $key = Get-ScriptBlockHash $Expression -BlockArgs $BlockArgs
+            if(!$Script:SessionCache.Value.ContainsKey($key))
+            {
+                $Script:SessionCache.Value[$key] = $Expression.InvokeReturnAsIs($BlockArgs)
+            }
+            return $Script:SessionCache.Value[$key]
+        }
+    }
+}

Get-PathUsage.ps1

@@ -0,0 +1,15 @@
+<#
+.SYNOPSIS
+Returns the list of directories in the path, and the commands found in each.
+#>
+
+#Requires -Version 7
+[CmdletBinding()] Param()
+$AllCommandPaths = Get-Command -Type Application,ExternalScript
+($env:Path -split ';') -replace '[/\\]\z' |
+    Where-Object {$AllCommandPaths -like "$_\*" |Measure-Object |Where-Object Count -lt 3} -pv pathitem |
+    ForEach-Object {[pscustomobject]@{ PathDirectory = $pathitem
+        Commands = @($AllCommandPaths |Where-Object Path -like "$pathitem\*")
+        PathExtMatch = @($env:PATHEXT -split ';' |
+            ForEach-Object {Get-ChildItem $pathitem -Filter "*$_"} |
+            Select-Object -ExpandProperty Name) }}