(SQL Server) Get XOAUTH2 Access Token from Google OAuth 2.0 Authorization Server

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

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @iTmp0 int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    -- This example assumes the Chilkat API to have been previously unlocked.
    -- See Global Unlock Sample for sample code.

    DECLARE @http int
    EXEC @hr = sp_OACreate 'Chilkat.Http', @http OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    -- --------------------------------------------------------------------------------
    -- 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
    -- --------------------------------------------------------------------------------
    -- Begin by loading your Google service account key (.p12)
    DECLARE @cert int
    EXEC @hr = sp_OACreate 'Chilkat.Cert', @cert OUT

    DECLARE @success int
    EXEC sp_OAMethod @cert, 'LoadPfxFile', @success OUT, 'c:/someDirectory/keys/chilkat25-cbd7b42afbd8.p12', 'notasecret'
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @cert, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @http
        EXEC @hr = sp_OADestroy @cert
        RETURN
      END

    -- The ISS is your service account email address ending in gserviceaccount.com.
    DECLARE @iss nvarchar(4000)
    SELECT @iss = 'chilkatsvc@chilkat25.iam.gserviceaccount.com'

    -- The scope is always the following string:
    DECLARE @scope nvarchar(4000)
    SELECT @scope = 'https://mail.google.com/'

    -- The sub is your company email address
    DECLARE @oauth_sub nvarchar(4000)
    SELECT @oauth_sub = 'bob@yourcompany.com'

    -- The access token is valid for this number of seconds.
    DECLARE @numSec int
    SELECT @numSec = 3600

    DECLARE @accessToken nvarchar(4000)
    EXEC sp_OAMethod @http, 'G_SvcOauthAccessToken', @accessToken OUT, @iss, @scope, @oauth_sub, @numSec, @cert
    EXEC sp_OAGetProperty @http, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN
        EXEC sp_OAGetProperty @http, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @http
        EXEC @hr = sp_OADestroy @cert
        RETURN
      END
    ELSE
      BEGIN

        PRINT 'access token: ' + @accessToken
      END

    -- The access token allows us to send unlimited emails while it's valid. Once it expires, we must obtain and use a new one.

    EXEC @hr = sp_OADestroy @http
    EXEC @hr = sp_OADestroy @cert


END
GO