Lua

Get OAuth 2.0 Access Token using G_SvcOauthAccessToken2

Obtains an OAUTH2 access token from the Google OAuth 2.0 Authorization Server using the G_SvcOauthAccessToken2 method. This is for Server to server applications using Google API's that need an access token. See https://developers.google.com/accounts/docs/OAuth2ServiceAccount Lua

local chilkat = require("chilkat")

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

-- --------------------------------------------------------------------------------
-- For a step-by-step guide for setting up your Google Workspace service account,
-- see Setup Google Workspace Account for Sending SMTP GMail from a Service Account
-- --------------------------------------------------------------------------------

local http = chilkat.Http.new()

-- When a service account (Client ID) is created at https://code.google.com/apis/console/
-- Google will generate a P12 key.  This is a PKCS12 (PFX) file that you will download
-- and save.  The password to access the contents of this file is "notasecret".
-- NOTE: The Chilkat Pfx API provides the ability to load a PFX/P12 and re-save
-- with a different password.

-- Begin by loading the downloaded .p12 into a Chilkat certificate object:
local cert = chilkat.Cert.new()
local success = cert:load_pfx_file("/myDir/API Project-1c43a291e2a1-notasecret.p12", "notasecret")
if not success then
    print(cert.last_error_text)
    return
end

-- The next (and final) step is to request the access token.  Chilkat internally
-- does all the work of forming the JWT header and JWT claim set, encoding and
-- signing the JWT, and sending the access token request.
-- The application need only provide the inputs: The iss, scope(s), sub, and the
-- desired duration with a max of 3600 seconds (1 hour).
--
-- Each of these inputs is defined as follows
-- (see https://developers.google.com/accounts/docs/OAuth2ServiceAccount
-- iss: The email address of the service account.
-- scope: A space-delimited list of the permissions that the application requests.
-- sub: The email address of the user for which the application is requesting delegated access.
-- numSec: The number of seconds for which the access token will be valid (max 3600).

local claimParams = chilkat.Hashtable.new()

-- The required claim parameters that must be provided by the application are
-- the "iss" and "scope" params:
success = claimParams:add_str("iss", "761326798069-r5mljlln1rd4lrbhg75efgigp36m78j5@developer.gserviceaccount.com")
success = claimParams:add_str("scope", "https://mail.google.com/")

-- The "sub" param is required if there is an email address, such as for a
-- Google Apps domain—if you use Google Apps for Work, where the administrator of the Google Apps domain
-- can authorize an application to access user data on behalf of users in the Google Apps domain.
--
-- Comment out this line if there is no such email address.
success = claimParams:add_str("sub", "user@your-domain.com")

-- The "aud" parameter is optional.  If not set, it defaults to the value shown here:
success = claimParams:add_str("aud", "https://accounts.google.com/o/oauth2/token")

local numSec = 3600

local accessToken = http:g_svc_oauth_access_token2(claimParams, numSec, cert)
if not http.last_method_success then
    print(http.last_error_text)
else
    print("access token: " .. accessToken)
end