VC Redist Installer - Add cached installer support and version checks

- Add parameters to support using a local cache (-ExistingInstallerFilesPath) and control behavior (-ForceCachedFilesOnly, -NoCheckLatestVersion).

- Change download target to the user's Downloads folder under "VCRedist Install"

- Detect remote installer version and choose between cached installers or downloading updated files.

Installer Scripts/Install VC Redist.ps1

@@ -1,3 +1,43 @@
+# Downloads the latest VC Redistributables from Microsoft
+
+param(
+    # Optional path to a local directory containing the installation files. If provided, the download steps will be skipped.
+    #   - Just copy the entire "VCRedist Install" folder with the files the script normally downloads, and put it in your mounted folder to avoid having to re-download it.
+    #   - Make sure to use the mounted path from the perspective of within the sandbox.
+    [string]$ExistingInstallerFilesPath,
+
+    # If set, forces using the installer files from ExistingInstallerFilesPath even if a new version exists. Still warns about there being a new version.
+    [switch]$ForceCachedFilesOnly,
+
+    # If set, implies ForceCachedFilesOnly and uses cached installer files only, but does not even bother checking for a latest version.
+    [switch]$NoCheckLatestVersion
+)
+
+# --- Parameter Usage Examples ---
+# Standard run (Download & Install):
+#    .\Install-VC-Redist.ps1
+#
+# Install from existing files instead of downloading:
+#    .\Install-VC-Redist.ps1 -ExistingInstallerFilesPath "C:\Users\WDAGUtilityAccount\Desktop\HostShared\VCRedist Install"
+#
+# Use cached files only, even if outdated (still warns about new versions):
+#    .\Install-VC-Redist.ps1 -ExistingInstallerFilesPath "C:\Users\WDAGUtilityAccount\Desktop\HostShared\VCRedist Install" -ForceCachedFilesOnly
+#
+# Use cached files only, skip all version checks:
+#    .\Install-VC-Redist.ps1 -ExistingInstallerFilesPath "C:\Users\WDAGUtilityAccount\Desktop\HostShared\VCRedist Install" -NoCheckLatestVersion
+
+# =======================================================
+
+# Validate parameter combinations
+if ($NoCheckLatestVersion) {
+    $ForceCachedFilesOnly = [switch]::new($true)
+}
+if ($ForceCachedFilesOnly -and [string]::IsNullOrWhiteSpace($ExistingInstallerFilesPath)) {
+    Write-Host "Error: -ForceCachedFilesOnly requires -ExistingInstallerFilesPath to be specified." -ForegroundColor Red
+    Read-Host "Press Enter to exit"
+    exit 1
+}
+
 # URLs for the latest Visual C++ Redistributables
 $urls = @(
     "https://aka.ms/vs/17/release/vc_redist.x86.exe",
@@ -7,33 +47,140 @@ if ($env:PROCESSOR_ARCHITECTURE -eq 'ARM64') {
     $urls += "https://aka.ms/vs/17/release/vc_redist.arm64.exe"
 }
 
-# Directory to save the downloads
+# Directory to save the downloads. This will save it into the user "Downloads" folder.
-$downloadPath = "$env:TEMP"
+$folderName = "VCRedist Install"
+$userDownloadsFolder = (New-Object -ComObject Shell.Application).Namespace('shell:Downloads').Self.Path
+$downloadPath = Join-Path -Path $userDownloadsFolder -ChildPath $folderName
 
-# To improve download performance, the progress bar is suppressed. [2, 6]
+# To improve download performance, the progress bar is suppressed.
 $ProgressPreference = 'SilentlyContinue'
 
+# Load stored version hashes from the pre-existing installer cache (read-only mount)
+$storedHashes = @{}
+if (-not [string]::IsNullOrWhiteSpace($ExistingInstallerFilesPath)) {
+    $hashFilePath = Join-Path $ExistingInstallerFilesPath "versions.txt"
+    if (Test-Path $hashFilePath) {
+        Get-Content $hashFilePath | ForEach-Object {
+            $parts = $_ -split '=', 2
+            if ($parts.Count -eq 2) { $storedHashes[$parts[0]] = $parts[1] }
+        }
+    }
+}
+
+# Track current remote hashes to save at the end
+$currentHashes = @{}
+$pauseAtEnd = $false
+
 foreach ($url in $urls) {
     $fileName = $url.Split('/')[-1]
-    $filePath = Join-Path $downloadPath $fileName
+    $downloadFilePath = Join-Path $downloadPath $fileName
+    $installerToRun = $null
+    $updateDetected = $false
+    $remoteHash = $null
 
-    Write-Host "Downloading $fileName..."
+    Write-Host "`nChecking $fileName..."
-    # Download the file without a progress bar [1, 4]
-    Invoke-WebRequest -Uri $url -OutFile $filePath
 
-    if (Test-Path $filePath) {
+    if (-not $NoCheckLatestVersion) {
-        Write-Host "Installing $fileName..."
+        try {
-        # Silently install the redistributable and wait for it to complete [3, 5, 9]
+            # Get the final redirected URL to extract the version hash
-        Start-Process -FilePath $filePath -ArgumentList "/install /quiet /norestart" -Wait
+            $headResponse = Invoke-WebRequest -Uri $url -Method Head -UseBasicParsing -ErrorAction Stop
-        Write-Host "$fileName has been installed."
+            if ($headResponse.BaseResponse.ResponseUri) {
-        # Optional: Remove the installer after installation
+                # PowerShell 5.1
-        # Remove-Item -Path $filePath
+                $finalUrl = $headResponse.BaseResponse.ResponseUri.AbsoluteUri
-    } else {
+            } else {
-        Write-Host "Error: Failed to download $fileName."
+                # PowerShell 7+
+                $finalUrl = $headResponse.BaseResponse.RequestMessage.RequestUri.AbsoluteUri
+            }
+            $remoteHash = $finalUrl.Split('/')[-2]
+            $currentHashes[$fileName] = $remoteHash
+            Write-Host "Remote hash: $remoteHash"
+        }
+        catch {
+            Write-Host "Warning: Could not retrieve remote info for $fileName." -ForegroundColor Yellow
+            Write-Host "Error Info: $_" -ForegroundColor Yellow
+        }
     }
+
+    # Check if a pre-existing cached installer can be used
+    if (-not [string]::IsNullOrWhiteSpace($ExistingInstallerFilesPath)) {
+        $cachedFilePath = Join-Path $ExistingInstallerFilesPath $fileName
+        if (Test-Path $cachedFilePath) {
+            if ($null -ne $remoteHash -and $storedHashes.ContainsKey($fileName) -and $storedHashes[$fileName] -eq $remoteHash) {
+                Write-Host "Cached version is up to date. Using $cachedFilePath"
+                $installerToRun = $cachedFilePath
+            } elseif ($ForceCachedFilesOnly) {
+                if ($null -ne $remoteHash) {
+                    Write-Host "WARNING: Cached installer is out of date, but using it anyway (-ForceCachedFilesOnly)." -ForegroundColor Yellow
+                    Write-Host "Please update your cache at: $ExistingInstallerFilesPath" -ForegroundColor Yellow
+                    $pauseAtEnd = $true
+                } else {
+                    Write-Host "Using cached file (version check skipped). Using $cachedFilePath"
+                }
+                $installerToRun = $cachedFilePath
+            } else {
+                Write-Host "Newer version detected. Cached installer is out of date." -ForegroundColor Yellow
+                $updateDetected = $true
+                $pauseAtEnd = $true
+            }
+        } elseif ($ForceCachedFilesOnly) {
+            Write-Host "Error: Cached file not found at $cachedFilePath and -ForceCachedFilesOnly is set." -ForegroundColor Red
+            continue
+        }
+    }
+
+    # Download if no valid cache was found or an update is needed
+    if ($null -eq $installerToRun) {
+        if ($ForceCachedFilesOnly) {
+            Write-Host "Error: No cached installer available for $fileName and -ForceCachedFilesOnly is set. Skipping." -ForegroundColor Red
+            continue
+        }
+
+        Write-Host "Downloading $fileName..."
+
+        # Create the directory if it doesn't exist
+        if (-not (Test-Path -Path $downloadPath)) {
+            New-Item -Path $downloadPath -ItemType Directory -Force | Out-Null
+        }
+
+        Invoke-WebRequest -Uri $url -OutFile $downloadFilePath -UseBasicParsing
+        $installerToRun = $downloadFilePath
+        
+        if ($updateDetected) {
+            Write-Host "ACTION REQUIRED: A new version of $fileName was downloaded." -ForegroundColor Yellow
+            Write-Host "Please update your cache at: $ExistingInstallerFilesPath" -ForegroundColor Yellow
+            Write-Host "Then update versions.txt with: $fileName=$remoteHash" -ForegroundColor Yellow
+            $pauseAtEnd = $true
+        }
+    }
+
+    if (Test-Path $installerToRun) {
+        Write-Host "Installing $fileName from $installerToRun..."
+        # Silently install the redistributable and wait for it to complete
+        Start-Process -FilePath $installerToRun -ArgumentList "/install /quiet /norestart" -Wait
+        Write-Host "$fileName has been installed."
+        
+        # Optional: Remove the downloaded installer if it was downloaded to TEMP
+        if ($installerToRun -eq $downloadFilePath) {
+            # Remove-Item -Path $downloadFilePath
+        }
+    } else {
+        Write-Host "Error: Failed to locate installer for $fileName."
+    }
+}
+
+# Save versions.txt to the download folder so it can be copied alongside the installers
+if ($currentHashes.Count -gt 0) {
+    if (-not (Test-Path -Path $downloadPath)) {
+        New-Item -Path $downloadPath -ItemType Directory -Force | Out-Null
+    }
+    $versionsFilePath = Join-Path $downloadPath "versions.txt"
+    $currentHashes.GetEnumerator() | ForEach-Object { "$($_.Key)=$($_.Value)" } | Set-Content $versionsFilePath
 }
 
 # Restore the default progress preference
 $ProgressPreference = 'Continue'
 
-Write-Host "Script execution finished."
+Write-Host "`nScript execution finished."
+if ($pauseAtEnd) {
+    Read-Host "`nPress Enter to exit"
+}