Download Chrome with curl.exe, then BITS, then Invoke-WebRequest

Invoke-WebRequest pushes every buffer through the pipeline and is the slowest
of the three by a wide margin; curl.exe ships in System32 on every supported
Windows and resumes a partial file with -C -, which matters on a 166 MB
download that gets interrupted. Also checks the finished file against
Content-Length, because a truncated MSI fails in msiexec with an error that
says nothing about why.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

scripts/enroll-chrome-management.ps1

@@ -92,21 +92,53 @@ if (-not $Remove -and -not (Find-Chrome)) {
 
     # Google's own enterprise MSI, which installs machine-wide and silently. We
     # are already elevated by this point, so this needs no second prompt.
+    $url = 'https://dl.google.com/dl/chrome/install/googlechromestandaloneenterprise64.msi'
     $msi = Join-Path $env:TEMP 'googlechromestandaloneenterprise64.msi'
     Write-Host 'Google Chrome is not installed — downloading it from Google (about 160 MB).'
 
-    # Progress off for the duration. Windows PowerShell re-renders the progress
-    # bar on every buffer, which on a 160 MB file costs far more time than the
-    # transfer itself — minutes instead of seconds, looking for all the world
-    # like a stalled download.
+    # Three ways down, fastest first. Invoke-WebRequest is last for a reason: it
+    # pushes every buffer through the PowerShell pipeline, and on Windows
+    # PowerShell it also re-renders the progress bar each time, which on a file
+    # this size costs more than the transfer itself — minutes rather than
+    # seconds, and indistinguishable from a stall while you watch it crawl.
+    $curl = Join-Path $env:SystemRoot 'System32\curl.exe'
+    if (Test-Path $curl) {
+        # -C - resumes a part-downloaded file rather than starting the 160 MB
+        # again, which matters when this is retried after an interruption.
+        & $curl -fL --retry 3 --retry-delay 2 -C - -o $msi $url
+        if ($LASTEXITCODE -ne 0) { Remove-Item $msi -ErrorAction SilentlyContinue }
+    }
+
+    if (-not (Test-Path $msi) -and (Get-Command Start-BitsTransfer -ErrorAction SilentlyContinue)) {
+        try {
+            Start-BitsTransfer -Source $url -Destination $msi -Priority Foreground -ErrorAction Stop
+        } catch {
+            Write-Host "BITS transfer failed ($($_.Exception.Message)); falling back."
+        }
+    }
+
+    if (-not (Test-Path $msi)) {
         $previousProgress = $ProgressPreference
         $ProgressPreference = 'SilentlyContinue'
         try {
-        Invoke-WebRequest -Uri 'https://dl.google.com/dl/chrome/install/googlechromestandaloneenterprise64.msi' `
-                          -OutFile $msi -UseBasicParsing
+            Invoke-WebRequest -Uri $url -OutFile $msi -UseBasicParsing
         } finally {
             $ProgressPreference = $previousProgress
         }
+    }
+
+    # A truncated download installs as a corrupt package, with an msiexec error
+    # that says nothing about the real cause.
+    $expected = 0
+    try {
+        $expected = [int64](Invoke-WebRequest -Uri $url -Method Head -UseBasicParsing).Headers['Content-Length']
+    } catch { }
+    $got = (Get-Item $msi -ErrorAction SilentlyContinue).Length
+    if (-not $got) { throw 'Chrome download produced no file.' }
+    if ($expected -gt 0 -and $got -ne $expected) {
+        Remove-Item $msi -ErrorAction SilentlyContinue
+        throw "Chrome download is incomplete ($got of $expected bytes). Re-run to resume."
+    }
 
     Write-Host 'Installing Chrome...'
     $msiexec = Start-Process msiexec.exe -Wait -PassThru -ArgumentList @('/i', "`"$msi`"", '/qn', '/norestart')