(Tcl) 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

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load ./chilkat.dll

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

set http [new_CkHttp]

CkHttp_put_AuthToken $http "ACCESS_TOKEN"
CkHttp_put_Accept $http "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".
set attachmentId "ANGjdJ-oy3aCuZISJKLAhUdaEksCEklbAPyMaWzFgqOMGbPCRkgwgeu_Kttd99C17OBTHROkDZGekibTKWXGfscB5ww7fw4E65_V1dQ-jHhb2TD1Cdm58-BbNw2iDxzptco8iILPiSnLLfFn5Ps7nsRcxHaGTt3r0yqFKCuIYNnPK1vM04BXI_cfzo-HnI4I3tD6oHNHOGVQrL01MdShFQjPELPUjXM8z1qs7Kom-QyvV1iOldUN-66UuhynsmDX-CMM5TIdB-8KD_lmdhf-0DqG8JnCA20XpXyfqwS8XFkPA-t-QSjb7SdkHQFtQ4lz2PcBREFzZ2eI5j0l0Y_dQHRPYTeMwkVl1yl4MfFT4C4iso3VSF-eqaIjiFCbXKCFNyeEIW5WFsv189dhlSqU"

set messageId "1712bc1dc22da2a2"

CkHttp_SetUrlVar $http "messageId" $messageId
CkHttp_SetUrlVar $http "attachmentId" $attachmentId

set 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=="
# }

set outputFilePath "qa_output/helloWorld.pdf"

# Download into a StringBuilder.
set sbJson [new_CkStringBuilder]

set success [CkHttp_DownloadSb $http $url "utf-8" $sbJson]
if {$success == 0} then {
    puts [CkHttp_lastErrorText $http]
    delete_CkHttp $http
    delete_CkStringBuilder $sbJson
    exit
}

if {[CkHttp_get_LastStatus $http] != 200} then {
    # Something failed.
    # the JSON contains an error message.
    puts [CkStringBuilder_getAsString $sbJson]
    delete_CkHttp $http
    delete_CkStringBuilder $sbJson
    exit
}

# Load into a Chilkat JSON object.
set json [new_CkJsonObject]

set success [CkJsonObject_LoadSb $json $sbJson]

# Extract the base64url data into a BinData.
set bd [new_CkBinData]

set success [CkJsonObject_BytesOf $json "data" "base64url" $bd]

# Save the data to a file.
set success [CkBinData_WriteFile $bd "qa_output/helloWorld.pdf"]

puts "Success."

delete_CkHttp $http
delete_CkStringBuilder $sbJson
delete_CkJsonObject $json
delete_CkBinData $bd