(PowerShell) Download GMail Message Attachment by ID

Demonstrates how to download a GMail email attachment by the attachment ID.

For more information, see https://developers.google.com/gmail/api/v1/reference/users/messages/attachments/get

Chilkat .NET Downloads Chilkat .NET Assemblies

Add-Type -Path "C:\chilkat\ChilkatDotNet47-9.5.0-x64\ChilkatDotNet47.dll"

# This example requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

$http = New-Object Chilkat.Http

$http.AuthToken = "ACCESS_TOKEN"
$http.Accept = "application/json"

# See the following example:  Get GMail Message (format=full)
# It shows how to download an email by message ID, and it shows how to parse the JSON
# response which includes attachment names, ids, and other information.

# This example will assume we already have the attachment id and filename.

# This is the attachment ID for a file named "helloWorld.pdf".
$attachmentId = "ANGjdJ-oy3aCuZISJKLAhUdaEksCEklbAPyMaWzFgqOMGbPCRkgwgeu_Kttd99C17OBTHROkDZGekibTKWXGfscB5ww7fw4E65_V1dQ-jHhb2TD1Cdm58-BbNw2iDxzptco8iILPiSnLLfFn5Ps7nsRcxHaGTt3r0yqFKCuIYNnPK1vM04BXI_cfzo-HnI4I3tD6oHNHOGVQrL01MdShFQjPELPUjXM8z1qs7Kom-QyvV1iOldUN-66UuhynsmDX-CMM5TIdB-8KD_lmdhf-0DqG8JnCA20XpXyfqwS8XFkPA-t-QSjb7SdkHQFtQ4lz2PcBREFzZ2eI5j0l0Y_dQHRPYTeMwkVl1yl4MfFT4C4iso3VSF-eqaIjiFCbXKCFNyeEIW5WFsv189dhlSqU"

$messageId = "1712bc1dc22da2a2"

$http.SetUrlVar("messageId",$messageId)
$http.SetUrlVar("attachmentId",$attachmentId)

$url = "https://www.googleapis.com/gmail/v1/users/userId/messages/{$messageId}/attachments/{$attachmentId}"

# When we download, the response is JSON that contains the attachment data base64url encoded, like this:
# {
#  "size": 934,
#  "data": "JVBERi0xLjM ... CiUlRU9GCg=="
# }

$outputFilePath = "qa_output/helloWorld.pdf"

# Download into a StringBuilder.
$sbJson = New-Object Chilkat.StringBuilder
$success = $http.DownloadSb($url,"utf-8",$sbJson)
if ($success -eq $false) {
    $($http.LastErrorText)
    exit
}

if ($http.LastStatus -ne 200) {
    # Something failed.
    # the JSON contains an error message.
    $($sbJson.GetAsString())
    exit
}

# Load into a Chilkat JSON object.
$json = New-Object Chilkat.JsonObject
$success = $json.LoadSb($sbJson)

# Extract the base64url data into a BinData.
$bd = New-Object Chilkat.BinData
$success = $json.BytesOf("data","base64url",$bd)

# Save the data to a file.
$success = $bd.WriteFile("qa_output/helloWorld.pdf")

$("Success.")