(Chilkat2-Python) OAuth2 for a GMail using a P12 Service Account Key

See more GMail REST API Examples

Note: This example does not work for Personal Google Accounts where the email domain is @gmail.com

For more information, see https://www.chilkatsoft.com/google_workspace_setup_smtp_gmail.asp

Chilkat2 Python Downloads install with pip pip3 install chilkat2 or download... Python Module for Windows, Linux, Alpine Linux, MacOS

import sys
import chilkat2

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

http = chilkat2.Http()

# --------------------------------------------------------------------------------
# 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)
cert = chilkat2.Cert()
success = cert.LoadPfxFile("c:/someDirectory/keys/chilkat25-cbd7b42afbd8.p12","notasecret")
if (success != True):
    print(cert.LastErrorText)
    sys.exit()

# The ISS is your service account email address ending in gserviceaccount.com.
iss = "chilkatsvc@chilkat25.iam.gserviceaccount.com"

# The scope is always the following string:
scope = "https://mail.google.com/"

# The sub is your company email address
oauth_sub = "bob@yourcompany.com"

# The access token is valid for this number of seconds.
numSec = 3600

accessToken = http.G_SvcOauthAccessToken(iss,scope,oauth_sub,numSec,cert)
if (http.LastMethodSuccess != True):
    print(http.LastErrorText)
    sys.exit()
else:
    print("access token: " + accessToken)

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

# -----------------------------------------------------------------------
mailman = chilkat2.MailMan()

# Set the properties for the GMail SMTP server:
mailman.SmtpHost = "smtp.gmail.com"
mailman.SmtpPort = 587
mailman.StartTLS = True

mailman.SmtpUsername = "bob@yourcompany.com"
mailman.OAuth2AccessToken = accessToken

# Create a new email object
email = chilkat2.Email()

email.Subject = "This is a test"
email.Body = "This is a test"
email.From = "Bob <bob@yourcompany.com>"
success = email.AddTo("Recipient","recipient@example.com")
# To add more recipients, call AddTo, AddCC, or AddBcc once per recipient.

success = mailman.SendEmail(email)
if (success != True):
    print(mailman.LastErrorText)
    sys.exit()

success = mailman.CloseSmtpConnection()
if (success != True):
    print("Connection to SMTP server not closed cleanly.")

print("Successfully sent email using Gmail with a service account key.")