Setting Python REQUESTS_CA_BUNDLE for Windows using all the available certificates on the machine. Answer to this Stackoverflow question: https://stackoverflow.com/questions/51925384/unable-to-get-local-issuer-certificate-when-using-requests-in-python

setPythonRequestsCaBundle.ps1

#Requires -Version 6.0

# Allocate a temporary directory for receiving the certificates
$tmpCertsDir = New-Item -Path "$env:TEMP" -Name "Certs$(Get-Date -Format FileDateTimeUniversal)" -ItemType Directory -Force

# Collect the certs from the local machine
$certs = Get-ChildItem -Path Cert:\ -Recurse | Where-Object -FilterScript { $_.Thumbprint }

# This will contain the paths to the resulting PEM files
$pemPaths = [string[]]::new($certs.Count)

$certs | ForEach-Object -Process {
    $curCert = $_.FriendlyName
    $i = $certs.IndexOf($_)
    if ([string]::IsNullOrEmpty($curCert)) {
        $curCert = $_.Subject
    }
    if ([string]::IsNullOrEmpty($curCert)) {
        $curCert = $_.Thumbprint
    }
    Write-Progress -Activity 'Copying certificates' -Status "Copying $curCert" -PercentComplete (100 * $i / $certs.Count)
    $outCert = Join-Path -Path $tmpCertsDir -ChildPath "$($_.Thumbprint).crt"
    $pemPaths[$i] = Join-Path -Path $export.Directory.FullName -ChildPath "$($export.BaseName).pem"
    
    if (-not (Test-Path -Path $outCert -PathType Leaf)) {
        $export = $_ | Export-Certificate -Type CERT -FilePath $outCert -Force
        openssl x509 -inform DER -in $export.FullName -out ($pemPaths[$i]) -text
    }
} -End {
    Remove-Item -Path $tmpCertsDir\*.crt -Force
    Write-Progress -Activity 'Copying certificates' -Status 'Done' -Completed
}
<# if you already have certifi installed, you can use
    $RequestsCaBundle = python -c 'import certifi; print(certifi.where())'  # "$Env:LOCALAPPDATA\Packages\PythonSoftwareFoundation.Python.3.11_qbz5n2kfra8p0\LocalCache\local-packages\Python311\site-packages\certifi\cacert.pem"
#>

<# Apparently, we aren't allowed to write into the site-packages directory, so this does not work
    $RequestsCaBundle = Join-Path -Path (python -c "import sys; [print(p) for p in sys.path if p.endswith(r'Lib\site-packages')]" | Sort-Object -Unique) -ChildPath "cacerts.pem"
#>

$RequestsCaBundle = "$env:USERPROFILE\cacerts.pem"  # Not sure if this is the best location for cacerts on Windows

$rcaTmp = New-TemporaryFile
for ($i = 0; $i -lt $pemPaths.Count; $i++) {
    Write-Progress -Activity 'Concatenating certificates' -Status "Concatenating $curCert" -PercentComplete (100 * $i / $pemPaths.Count)
    $pemPaths[$i] | Get-Content | Add-Content -Path $rcaTmp -Force
}

Remove-Item -Path $tmpCertsDir -Recurse -Force

try {
    Move-Item -Path $rcaTmp -Destination $RequestsCaBundle -Force -ErrorAction Stop
}
catch [System.UnauthorizedAccessException] {
    if (-not(Test-Path -Path $RequestsCaBundle -PathType Leaf) -and $rcaTmp.Length -gt 0) {
        
        $errOut = New-TemporaryFile
        # Move $rcaTmp to $RequestsCaBundle using RunAs verb
        Start-Process -FilePath pwsh -ArgumentList @('NonInteractive', 'NoProfile', 'NoLogo', "-Command `"try { Move-Item -Path '$rcaTmp' -Destination '$RequestsCaBundle' -Force *>&1 }catch{`$_} ) | Export-Clixml -Path $errOut -Force`"") -Verb RunAs
        if ($errOut.Length -gt 0) {
            Import-Clixml -Path $errOut | Write-Error
        }
        Remove-Item -Path $errOut
    }        
}
if (Test-Path -Path $RequestsCaBundle -PathType Leaf) {
    $env:REQUESTS_CA_BUNDLE = "$RequestsCaBundle"
    try {
        [System.Environment]::SetEnvironmentVariable('REQUESTS_CA_BUNDLE',$RequestsCaBundle,[System.EnvironmentVariableTarget]::Machine)
    }
    catch [System.Management.Automation.MethodInvocationException] {
        $errOut = New-TemporaryFile
        # Set the REQUESTS_CA_BUNDLE environment variable at the machine scope using RunAs verb
        Start-Process -FilePath pwsh -ArgumentList @('NonInteractive', 'NoProfile', 'NoLogo', "-Command `"try { [System.Environment]::SetEnvironmentVariable('REQUESTS_CA_BUNDLE',$RequestsCaBundle,[System.EnvironmentVariableTarget]::Machine) *>&1 }catch{`$_} ) | Export-Clixml -Path $errOut -Force`"") -Verb RunAs
        if ($errOut.Length -gt 0) {
            Import-Clixml -Path $errOut | Write-Error
        }
        Remove-Item -Path $errOut
    }
}
else {
    Write-Warning "Unable to write to '$RequestsCaBundle'; Check permissions and try again."
}