A Firefox Quantum ViewSourceWith extension workaround with Firefox's source.editor.external

ViewSourceWith.ps1

# A Firefox Quantum ViewSourceWith replacement for Windows
#
# Usage:
#  (1) Save as C:\path\to\script.ps1
#  (2) In order to run your own powershell scripts, start PowerShell
#      as Administrator and run the command
#
#         Set-ExecutionPolicy RemoteSigned
#
#  (2) You can test the proper running (from a user cmd):
#
#         cd C:\path\to\
#         # Create a "test.html" with some content here
#         powershell.exe ".\test.ps1" -filename "test.html"
#
#  (3) Determine the absolute path to powershell.exe from powershell itself
#      via
#
#         (Get-Command powershell).Path
#
#  (4) In Firefox, edit about:config the following way:
#
#         view_source.editor.external = true
#         view_source.editor.path = "Path\to\powershell.exe"
#         view_source.editor.args = "C:\path\to\script.ps1 -filename"
#
#  (5) Click "View source with" in any Firefox tab. If it doesn't fire up
#      Powershell, try the browser console to read what's the error.
#      Firefox view_source.editor call arguments seems to be put together
#      in https://searchcode.com/codesearch/view/18535188/ line 100
#      also
#       https://hg.mozilla.org/mozilla-central/file/0e91a598b99e/toolkit/components/viewsource/content/viewSourceUtils.js
#       line 170
#
#  (6) Include -noexit as argument to debug the script in case of errors.
# 
#
# Written by SvenK on 2017-11-17 for Public Domain, intentionally for t29.
#

### my arguments were:
####  args = "C:\Users\Sven\Desktop\test.ps1" -noexit -filename 
####  path = C:\WINDOWS\System32\WindowsPowerShell\v1.0\powershell.exe

# Problem so far: Firefox somehow not properly escapes the arguments and
# with powershell it is a pain to look into the reason for that.

#### -> will probably write a C++ file (mingw) instead.

param (
# Single parameter: A path to a HTML file
    [Parameter(Mandatory=$true)][string]$filename
)

# show windows 10 toast notification
Function My-Show-Notification {
	Param($Text)
	$ErrorActionPreference = "Stop"
	$notificationTitle = $Text

	[Windows.UI.Notifications.ToastNotificationManager, Windows.UI.Notifications, ContentType = WindowsRuntime] > $null
	$template = [Windows.UI.Notifications.ToastNotificationManager]::GetTemplateContent([Windows.UI.Notifications.ToastTemplateType]::ToastText01)

	#Convert to .NET type for XML manipuration
	$toastXml = [xml] $template.GetXml()
	$toastXml.GetElementsByTagName("text").AppendChild($toastXml.CreateTextNode($notificationTitle)) > $null

	#Convert back to WinRT type
	$xml = New-Object Windows.Data.Xml.Dom.XmlDocument
	$xml.LoadXml($toastXml.OuterXml)

	$toast = [Windows.UI.Notifications.ToastNotification]::new($xml)
	$toast.Tag = "PowerShell"
	$toast.Group = "PowerShell"
	$toast.ExpirationTime = [DateTimeOffset]::Now.AddMinutes(5)
	#$toast.SuppressPopup = $true

	$notifier = [Windows.UI.Notifications.ToastNotificationManager]::CreateToastNotifier("PowerShell")
	$notifier.Show($toast);
}

My-Show-Notification("called with filename=$filename")

# if you would slurp the HTML from a URL
# $URI="http://technikum29.de/de/"
# $Response = Invoke-WebRequest -Uri $URI
# $HTML = $Response.ParsedHtml

# instead, read the HTML file
$HTML = New-Object -Com "HTMLFile"
$HTML.IHtmlDocument2_write($(Get-content $filename -raw))

# from hereon, implement your own logic. Here, we look up the local
# filename from a meta tag such as
#   <meta name="$meta_fieldname" content="C:\somewhere\over\the\rainbow.html">

# the meta tag name where to get the information from
$meta_fieldname = "author"

# the editor to start
$editor = 'C:\Program Files (x86)\Notepad++\notepad++.exe'

# query content of the specific meta tag
$new_filename = ($HTML.getElementsByTagName('meta') | where {$_.name -eq $meta_fieldname }).content

# check if that file exists
if([string]::IsNullOrEmpty($new_filename)) {
    My-Show-Notification("Sourcecode is not one of our websites, opening raw HTML.")
	$new_filename = $filename
} elseif(!([System.IO.File]::Exists($new_filename))) {
    My-Show-Notification("Determined file location '$new_filename' does not exist, opening raw HTML instead")
	$new_filename = $filename
} else {
    My-Show-Notification("Found file location at $new_filename")
}

# Safely escape the command arguments:
#$command = "& "editor --%" + $new_filename

# does not work. Do the stupid instead:
& $editor "$new_filename"

Note the status: Doesn't work for me on Windows currently.