Get-PowerShellAssemblyMetadata.ps1

# Copyright: (c) 2024, Jordan Borean (@jborean93) <jborean93@gmail.com>
# MIT License (see LICENSE or https://opensource.org/licenses/MIT)

Function Get-PowerShellAssemblyMetadata {
    <#
    .SYNOPSIS
    Gets the cmdlets and aliases in a dotnet assembly.

    .PARAMETER Path
    The assembly to inspect.

    .EXAMPLE
    Get-PowerShellAssemblyMetadata -Path MyModule.dll

    .NOTES
    This requires the System.Reflection.MetadataLoadContext assembly to be
    loaded through Add-Type. WinPS (5.1) will also need to load its deps
        System.Memory
        System.Collections.Immutable
        System.Reflection.Metadata
        System.Runtime.CompilerServices.Unsafe
        
    https://www.nuget.org/packages/System.Reflection.MetadataLoadContext
    #>
    [CmdletBinding()]
    param (
        [Parameter(Mandatory)]
        [string]
        $Path
    )

    $resolver = [System.Reflection.PathAssemblyResolver]::new(
        [string[]]@(
            (Get-ChildItem -Path ([System.Runtime.InteropServices.RuntimeEnvironment]::GetRuntimeDirectory()) -Filter "*.dll").FullName
            $Path
        ))
    $context = [System.Reflection.MetadataLoadContext]::new($resolver)
    try {
        $smaAssembly = $context.LoadFromAssemblyPath([PSObject].Assembly.Location)
        $cmdletType = $smaAssembly.GetType('System.Management.Automation.Cmdlet')
        $cmdletAttribute = $smaAssembly.GetType('System.Management.Automation.CmdletAttribute')
        $aliasAttribute = $smaAssembly.GetType('System.Management.Automation.AliasAttribute')

        $assembly = $context.LoadFromAssemblyPath($Path)

        $cmdletsToExport = [System.Collections.Generic.List[string]]::new()
        $aliasesToExport = [System.Collections.Generic.List[string]]::new()
        $assembly.GetTypes() | Where-Object {
            $_.IsSubclassOf($cmdletType)
        } | ForEach-Object -Process {
            $cmdletInfo = $_.CustomAttributes | Where-Object { $_.AttributeType -eq $cmdletAttribute }
            if (-not $cmdletInfo) { return }

            $name = "$($cmdletInfo.ConstructorArguments[0].Value)-$($cmdletInfo.ConstructorArguments[1].Value)"
            $cmdletsToExport.Add($name)

            $aliases = $_.CustomAttributes | Where-Object { $_.AttributeType -eq $aliasAttribute }
            if (-not $aliases -or -not $aliases.ConstructorArguments.Value) { return }
            $aliasesToExport.AddRange([string[]]@($aliases.ConstructorArguments.Value.Value))
        }

        [PSCustomObject]@{
            CmdletsToExport = $cmdletsToExport
            AliasesToExport = $aliasesToExport
        }
    }
    finally {
        $context.Dispose()
    }
}