Lua

Download GMail Message Attachment by ID

See more GMail REST API Examples

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

local chilkat = require("chilkat")

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

local http = chilkat.Http.new()

http.auth_token = "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".
local attachmentId = "ANGjdJ-oy3aCuZISJKLAhUdaEksCEklbAPyMaWzFgqOMGbPCRkgwgeu_Kttd99C17OBTHROkDZGekibTKWXGfscB5ww7fw4E65_V1dQ-jHhb2TD1Cdm58-BbNw2iDxzptco8iILPiSnLLfFn5Ps7nsRcxHaGTt3r0yqFKCuIYNnPK1vM04BXI_cfzo-HnI4I3tD6oHNHOGVQrL01MdShFQjPELPUjXM8z1qs7Kom-QyvV1iOldUN-66UuhynsmDX-CMM5TIdB-8KD_lmdhf-0DqG8JnCA20XpXyfqwS8XFkPA-t-QSjb7SdkHQFtQ4lz2PcBREFzZ2eI5j0l0Y_dQHRPYTeMwkVl1yl4MfFT4C4iso3VSF-eqaIjiFCbXKCFNyeEIW5WFsv189dhlSqU"

local messageId = "1712bc1dc22da2a2"

http:set_url_var("messageId", messageId)
http:set_url_var("attachmentId", attachmentId)

local 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=="
-- }

local outputFilePath = "qa_output/helloWorld.pdf"

-- Download into a StringBuilder.
local sbJson = chilkat.StringBuilder.new()
local success = http:download_sb(url, "utf-8", sbJson)
if not success then
    print(http.last_error_text)
    return
end

if http.last_status ~= 200 then
    -- Something failed.
    -- the JSON contains an error message.
    print(sbJson:get_as_string())
    return
end

-- Load into a Chilkat JSON object.
local json = chilkat.JsonObject.new()
success = json:load_sb(sbJson)

-- Extract the base64url data into a BinData.
local bd = chilkat.BinData.new()
success = json:bytes_of("data", "base64url", bd)

-- Save the data to a file.
success = bd:write_file("qa_output/helloWorld.pdf")

print("Success.")