Powershell - Versenden von EML Dateien

<#
    Resend bunch of *.eml files in a folder / (c) @colinardo
#>

function Load-NugetAssembly {
    [CmdletBinding()]
    param(
        [string]$url,
        [string]$name,
        [string]$zipinternalpath,
        [switch]$downloadonly
    )
    if($psscriptroot -ne ''){  
        $localpath = join-path $psscriptroot $name
    }else{
        $localpath = join-path $env:TEMP $name
    }
    $tmp = "$env:TEMP\$([IO.Path]::GetRandomFileName())"  
    $zip = $null
    try{
        if(!(Test-Path $localpath)){
            Add-Type -A System.IO.Compression.FileSystem
            write-host "Downloading and extracting required library '$name' ... " -F Green -NoNewline  
            (New-Object System.Net.WebClient).DownloadFile($url, $tmp)
            $zip = [System.IO.Compression.ZipFile]::OpenRead($tmp)
            $zip.Entries | ?{$_.Fullname -eq $zipinternalpath} | %{
                [System.IO.Compression.ZipFileExtensions]::ExtractToFile($_,$localpath)
            }
	        Unblock-File -Path $localpath
            write-host "OK" -F Green  
        }
        if(!$downloadonly.IsPresent){
            Add-Type -Path $localpath -EA Stop
        }
        
    }catch{
        write-host ($_.Exception.LoaderExceptions | fl | out-string)
        throw "Error: $($_.Exception.Message)"  

    }finally{
        if ($zip){$zip.Dispose()}
        if(Test-Path $tmp){del $tmp -Force}
    }  
}

# load required assemblies if not already loaded
if (!('MailKit.Net.Smtp.SmtpClient' -as [type])){  
    Load-NugetAssembly 'https://www.nuget.org/api/v2/package/Portable.BouncyCastle/1.8.8' -name 'BouncyCastle.Crypto.dll' -zipinternalpath 'lib/net40/BouncyCastle.Crypto.dll' -EA Stop  
    Load-NugetAssembly 'https://www.nuget.org/api/v2/package/System.Buffers/4.5.1' -name 'System.Buffers.dll' -zipinternalpath 'lib/net461/System.Buffers.dll' -EA Stop  
    Load-NugetAssembly 'https://www.nuget.org/api/v2/package/MimeKit/2.10.1' -name 'MimeKit.dll' -zipinternalpath 'lib/net45/MimeKit.dll' -EA Stop  
    Load-NugetAssembly 'https://www.nuget.org/api/v2/package/MailKit/2.10.1' -name 'MailKit.dll' -zipinternalpath 'lib/net45/MailKit.dll' -EA Stop     
}


# folder with eml files
$folder = "D:\temp\mails"  

$options = $null; $smtp = $null
try{
    # create parser options object
    $options = New-Object MimeKit.ParserOptions
    # create smtp client
    $smtp = New-Object MailKit.Net.Smtp.SmtpClient
    # set accepted tls protocols
    $smtp.SslProtocols = 'Tls11','Tls12','Tls13'  
    # connect to smtp server
    $smtp.Connect("smtp.domain.tld",587,$false)  
    # authenticate with smtp server with username/password
    $smtp.Authenticate("USERNAME",'PASSWORD')  
}catch{
    Write-Error -Message $_.Exception.Message
    return
}

# for each *.eml in folder
foreach($file in Get-ChildItem $folder -File -Filter *.eml){
    try{
        write-host "Sending mail '$($file.Fullname)' ... " -F Green -NoNewline  
        # load eml message
        $msg = [MimeKit.MimeMessage]::Load($options,$file.Fullname)

        # (optional) to add additional recipients (CC/BCC/TO) to the mails you can use the following scheme (uncomment and change recipient)
        # $msg.BCC.Add('user@domain.tld')  
        # $msg.CC.Add('user@domain.tld')  
        # $msg.TO.Add('user@domain.tld')  

        # send message
        $smtp.Send($msg)
        write-host "OK" -F Green  
    }catch{
        Write-Error -Message "Error loading or sending message: $($_.Exception.Message)"   
    }
}

# cleanup
if ($smtp){
    $smtp.Disconnect($true)
    $smtp.Dispose()
}