Powershell: Googlemail (GMail) nativ mit Powershell verwalten

# ANPASSUNGEN HIER VORNEHMEN ===========================================================

# Client API Zugangsdaten hier eintragen
$client_id = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxx.apps.googleusercontent.com'  
$client_secret = 'xxxxxxxxxxxxxxxxxxxxxxxxx'  
# Array der Bereiche die autorisiert werden sollen (In diesem Beispiel erhält die Anwendung Vollzugriff auf alle GMail Funktionen)
$global:scopes = @('https://mail.google.com/')  
# Pfad in dem das Refresh-Token gespeichert wird mit dem man ein neues Access Token anfordert (Standardmäßig der Ordner in dem das Skript liegt)
$global:token_path = "$(Split-Path $PSCommandPath -Parent)\refresh.token"  
# E-Mail-Adresse des Google-Kontos
$global:gmail_email = 'USER@GMAIL.COM'  

# ENDE EINRICHTUNG =====================================================================

<#
    #####################################################
    ###### Google GMAIL-Verwaltung (c) @colinardo #######
    #####################################################
    -> benötigt wird mind. PS Version 3.0
#>

# ANPASSUNGEN HIER VORNEHMEN ===========================================================

# Client API Zugangsdaten hier eintragen
$client_id = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxx.apps.googleusercontent.com'  
$client_secret = 'xxxxxxxxxxxxxxxxxxxxxxxxx'  
# Array der Bereiche die autorisiert werden sollen (In diesem Beispiel erhält die Anwendung Vollzugriff auf alle GMail Funktionen)
$global:scopes = @('https://mail.google.com/')  
# Pfad in dem das Refresh-Token gespeichert wird mit dem man ein neues Access Token anfordert (Standardmäßig der Ordner in dem das Skript liegt)
$global:token_path = "$(Split-Path $PSCommandPath -Parent)\refresh.token"  
# E-Mail-Adresse des Google-Kontos
$global:gmail_email = 'USER@GMAIL.COM'  

# ENDE EINRICHTUNG =====================================================================

Add-Type -AssemblyName System.Windows.Forms

# Accept all TLS protocols
[System.Net.ServicePointManager]::SecurityProtocol = [System.Net.SecurityProtocolType]::GetNames([System.Net.SecurityProtocolType])

<# 
    -------------------------------------------------------------------------------------------
    Funktion: Auth-Google - Haupt-Authentifizierungsfunktion (OAuth 2.0) für Zugriffe auf die Google-Dienste
    -------------------------------------------------------------------------------------------
#>
function Auth-Google {
    # Wenn refresh.token Datei vorhanden lese Token aus
    if ((Test-Path $global:token_path)){
        $content = gc $global:token_path -TotalCount 1
        if ($content.length -gt 0){$global:refresh_token = $content}
    }
    # wenn kein Refresh-Token vorhanden ist, initiale Authorization starten ...
    if(!$global:refresh_token){
        $url = "https://accounts.google.com/o/oauth2/auth?scope=$($global:scopes -join " ")&redirect_uri=urn:ietf:wg:oauth:2.0:oob&response_type=code&client_id=$client_id"  
        # Manuelle Authorization mit Userinteraktion
        write-host "Starting Authorization Request in Browser ... (Please Login into your Google-Account, and accept the authorization request, copy the returned code and close the Browser-Window !" -ForegroundColor Green  
        Start-Process "iexplore.exe" -ArgumentList $url -Wait  
        $authcode = [System.Windows.Forms.Clipboard]::GetText()
        
        $requestbody = @{
        "code"=$authcode  
        "client_id"=$client_id  
        "client_secret"=$client_secret  
        "redirect_uri"='urn:ietf:wg:oauth:2.0:oob'  
        "grant_type"="authorization_code"  
        }
    
        $result = Invoke-RestMethod 'https://www.googleapis.com/oauth2/v3/token' -Method Post -Body $requestbody  
        $global:refresh_token = $result.refresh_token
        set-content $global:token_path -Value $global:refresh_token
        $global:access_token = $result.access_token
        $global:token_expires = $result.expires_in
        $global:token_created = get-date
        return $true
    }else{
        # kein access_token vorhanden => neues access_token via refresh holen
        if (!$global:access_token){
            write-host "Refreshing access_token ..."  
            $requestbody = @{
            "refresh_token"=$global:refresh_token  
            "client_id"=$client_id  
            "client_secret"=$client_secret  
            "grant_type"="refresh_token"  
            }
            Try{
                $tokenrequest = Invoke-RestMethod 'https://www.googleapis.com/oauth2/v3/token' -Method Post -Body $requestbody -EA Stop  
                $global:access_token = $tokenrequest.access_token
                $global:token_created = get-date
                $global:token_expires = $tokenrequest.expires_in
                return $true
            }catch{
                write-host $_.Exception.Message
                return $false
            }
        }else{
            # access_token vorhanden, überprüfe ob es abgelaufen ist
            if((((get-date) - $global:token_created).TotalSeconds) -ge $global:token_expires){
                # access_token ist abgelaufen => fordere ein neues an
                write-host "Access Token has expired ..."  
                $global:access_token = ""  
                Auth-Google
            }else{
                # gültiges access_token vorhanden
                return $true
            }
        }
    }
}

<# 
    ------------------------------------
    Funktion: Get-GoogleMails
    ------------------------------------
#>
function Get-GoogleMails([string[]]$labels = @('INBOX','UNREAD'),[switch]$includespamtrash,[string]$query,[switch]$raw,[int]$maxResults = 100000){  
    if(!(Auth-Google)){
        return $false 
    }
    Try{
        $param_spam = $(if($includespamtrash.IsPresent){'&includeSpamTrash=true'}else{'&includeSpamTrash=false'})  
        $param_format = $(if($raw.IsPresent){'&format=raw'}else{'&format=full'})  
        $param_labels = $(if($labels){'&labelIds=' + $($labels -join '&labelIds=')})  
        $param_query = $(if($query){"&q=$([System.Net.WebUtility]::UrlEncode($query))"})  
        $uri = "https://www.googleapis.com/gmail/v1/users/$([System.Net.WebUtility]::UrlEncode($global:gmail_email))/messages?access_token=$($global:access_token)$param_labels$param_spam$param_query&maxResults=$maxResults"  
        $result = Invoke-RestMethod $uri -Method Get -ErrorAction Stop
        $mails = @()
        $result.messages.id | %{
            $messageId = $_
            $mail = irm -Uri "https://www.googleapis.com/gmail/v1/users/$($global:gmail_email)/messages/$($messageId)?access_token=$($global:access_token)$param_format" -Method Get -EA Stop  
            # UNIX Datum umwandeln
            $mail | add-member -MemberType NoteProperty -Name "Date" -Value ([timezone]::CurrentTimeZone.ToLocalTime(([datetime]'1/1/1970').AddMilliseconds($mail.internalDate)))  
            # Simplen Body extrahieren
            if ($mail.payload.body.data){
                $b64data = $mail.payload.body.data.replace('-','+').replace('_','/')  
                $mail | add-member -MemberType NoteProperty -Name 'Body' -Value ([System.Text.Encoding]::UTF8.GetString([convert]::FromBase64String($b64data)))  
            }
            # Attachments extrahieren
            if ($mail.payload.parts){
                $mail | add-member -MemberType NoteProperty -Name "Attachments" -Value @()  
                $mail.payload.parts | %{
                    if($_.filename -ne "" -and $_.body.attachmentId -ne $null){  
                     # part ist ein Attachment
                        $attachment = irm -uri "https://www.googleapis.com/gmail/v1/users/$($global:gmail_email)/messages/$($messageId)/attachments/$($_.body.attachmentId)?access_token=$($global:access_token)$param_format" -Method Get -EA Stop  
                        # custom attachment object mit den wichtigsten Daten erstellen und Umwandlung der Base64 Daten in Byte-Array
                        $attachment_object = New-Object PSObject -Property @{'Name'=$_.filename;'Size'=$attachment.Size;'Data'=[convert]::FromBase64String($attachment.data.replace('-','+').replace('_','/'))}  
                        # Methode zum Speichern des Attachments hinzufügen
                        $attachment_object | add-member -MemberType ScriptMethod -Name SaveAs -Value {param([parameter(mandatory=$true)][ValidateNotNullOrEmpty()][string]$filepath)[System.IO.File]::WriteAllBytes($filepath,$this.Data)}
                        $mail.Attachments += $attachment_object
                    }
                }
            }
            # Header leichter zugänglich machen
            if($mail.payload.headers){
                $headers = @{}
                $mail.payload.headers | %{$headers[$_.name] += @($_.value)}
                $mail | add-member -MemberType NoteProperty -Name Headers -Value $headers
            }
            if($mail.raw){
                $b64data = $mail.raw.replace('-','+').replace('_','/') # google benutzt eine andere Base64 Tabelle  
                $mail | add-member -MemberType NoteProperty -Name "Body" -Value ([System.Text.Encoding]::UTF8.GetString([convert]::FromBase64String($b64data)))  
            }
            # mail zum Array hinzufügen
            $mails += $mail
        }
        return $mails
        
    }catch [System.Net.WebException]{
        write-host $_.Exception.Message -F Red
        return $false
    }
}
<# 
    ----------------------------------------
    Funktion: Set-GoogleMailLabels
    ----------------------------------------
#>
function Set-GoogleMailLabels([string]$messageid,[string[]]$addlabels,[string[]]$removeLabels){
        if(!(Auth-Google)){
        return $false 
    }
    Try{
        $body_labels = @{}
        if($removeLabels){$body_labels."removeLabelIds" = $removelabels}  
        if($addlabels){$body_labels."addLabelIds" = $addlabels}  
        $body_labels = $body_labels | ConvertTo-JSON

        $uri = "https://www.googleapis.com/gmail/v1/users/$([System.Net.WebUtility]::UrlEncode($global:gmail_email))/messages/$($messageid)/modify?access_token=$($global:access_token)"  
        $result = Invoke-RestMethod $uri -Method POST -ErrorAction Stop -Body $body_labels -ContentType "application/json"  
        return $result
    }catch [System.Net.WebException]{
        write-host $_.Exception.Message -F Red
        return $false
    }
}

<# 
    ----------------------------------------
    Funktion: Remove-GoogleMailMessage
    ----------------------------------------
#>
function Remove-GoogleMailMessage([string]$messageid){
    if(!(Auth-Google)){
        return $false 
    }
    Try{
        $uri = "https://www.googleapis.com/gmail/v1/users/$([System.Net.WebUtility]::UrlEncode($global:gmail_email))/messages/$($messageid)?access_token=$($global:access_token)"  
        return irm $uri -Method Delete -ErrorAction Stop
    }catch [System.Net.WebException]{
        write-host $_.Exception.Message -F Red
        return $false
    }
}

<# 
    ----------------------------------------
    Funktion: Send-GoogleMailMessage
    ----------------------------------------
#>
function Send-GoogleMailMessage([string]$from = $global:gmail_email,[string[]]$to,[string[]]$cc,[string[]]$bcc,[string]$subject,[string]$body,[switch]$IsHtml,[string[]]$attachments){
        if(!(Auth-Google)){
        return $false 
    }
    Try{
        $mail = new-Object System.Net.Mail.MailMessage
        $mail.From = $from
        $to | %{$mail.to.Add($_)}
        if($cc){$cc | %{$mail.cc.Add($_)}}
        if($bcc){$bcc | %{$mail.Bcc.Add($_)}}
        if($attachments){$attachments | %{$mail.Attachments.Add($_)}}
        $mail.Subject = $subject
        $mail.Body = $body
        $mail.IsBodyHtml = $(if($IsHtml.IsPresent){$true}else{$false})
        $mail.BodyEncoding = [System.Text.Encoding]::UTF8
        $mail.BodyTransferEncoding = [System.Net.Mime.TransferEncoding]::Base64

        $flags = [System.Reflection.BindingFlags]::Instance -bor [System.Reflection.BindingFlags]::NonPublic
        $MailWriter = [System.Net.Mail.SmtpClient].Assembly.GetType("System.Net.Mail.MailWriter")  
        $MailWriterConstructor = $MailWriter.GetConstructor($flags,$null,([System.IO.Stream]),$null)
        $sendMethod = [System.Net.Mail.MailMessage].GetMethod("Send",$flags)  
        $closeMethod = [System.Net.Mail.MailMessage].GetMethod("Close",$flags)  
        $result = New-Object System.IO.MemoryStream
        $writer = $MailWriterConstructor.Invoke($result)
        $sendMethod.Invoke($mail,$flags,$null,@($writer,$true,$true),$null)
        $b64String = [System.Convert]::ToBase64String($result.toArray())
        $result.Close(); $result.Dispose()

        $body = @{
            "raw" = $b64String  
        } | ConvertTo-Json
        $uri = "https://www.googleapis.com/gmail/v1/users/$([System.Net.WebUtility]::UrlEncode($global:gmail_email))/messages/send?access_token=$($global:access_token)"  
        $result = Invoke-RestMethod $uri -Method POST -ErrorAction Stop -Body $body -ContentType "application/json"  
        return $result
    }catch [System.Net.WebException]{
        write-host $_.Exception.Message -F Red
        return $false
    }
}

$mails = Get-GoogleMails -labels @("INBOX")  

$mails = Get-GoogleMails -query 'has:attachment' -labels @("INBOX")  
$mails | %{
    write-host "Mail: $($_.Headers.Subject)" -F Green  
    $_.Attachments
}

$mails = Get-GoogleMails -query 'has:attachment' -labels @("INBOX")  
$mails | %{
    write-host "Mail: $($_.Headers.Subject)" -F Green  
    $_.Attachments | %{
        $_.SaveAs("<PFAD für das ATTACHMENT>")  
   }
}

Set-GoogleMailLabels -messageid $mails.id -removelabels "UNREAD"

Remove-GoogleMailMessage -messageid $mails.id

Send-GoogleMailMessage -to "user@domain.de" -subject "Testsubject" -body "Mein Body kann auch <strong>HTML</strong> enthalten." -IsHtml -attachments 'C:\test.txt'