How to use Extism .NET SDK with PowerShell

[StSchnell]

I read in the overview of run WebAssembly in your app, that the .NET SDK supports C# and F#. As far as I know, nearly everything that is possible with C# should also possible with PowerShell. So I implemented the approach shown in the example how to create a plug-in in PowerShell. In this case, I read the WASM file from a local source that exists in the same directory as the PowerShell script.

Here the code:

<#
 # fileName: count_vowels.ps1
 #
 # Checked with PowerShell 7.5.0 Core on Windows 11 and RHEL 9
 #>


[System.String]$LibDir = $($PSScriptRoot)
[System.String]$Extism = $($LibDir) + "/Extism.Sdk.dll"
Add-Type -Path $Extism


function Main {

  [System.String]$wasmFileName = "$($PSScriptRoot)/count_vowels.wasm"

  try {

    [System.Array]$wasmFileArrayOfBytes = `
      Get-Content -Path $wasmFileName -AsByteStream -Raw

    $wasmArray = [Extism.Sdk.ByteArrayWasmSource]::new( `
      $wasmFileArrayOfBytes, `
      "count_vowels.wasm" `
    )

    $Manifest = [Extism.Sdk.Manifest]::new($wasmArray)

    $Options = [Extism.Sdk.PluginIntializationOptions]::new()
    $Options.WithWasi = $True

    $HostFunctionArray = [Extism.Sdk.HostFunction[]]::new(0)

    $Plugin = [Extism.Sdk.Plugin]::new($Manifest, $HostFunctionArray, $Options)

    $output = $Plugin.Call("count_vowels", "Hello World from Stefan")
    Write-Host $output # {"count":6,"vowels":"aeiouAEIOU"}

  } catch {
    Write-Host "An error occurred:"
    Write-Host $_
  }

}


Main

It works perfectly.

The PowerShell script approach offers further perspectives for the use of Extism and WebAssembly.

[mhmd-azeez]

Very cool! thank you very much for posting the tutorial here!

[nilslice]

Super cool!