下面是一个Gmail API的例子。虽然比较复杂，但这是我发现在2019年唯一有效的方法。这个例子是从以下例子中获取并修改的:

https://developers.google.com/gmail/api/guides/sending

你需要通过谷歌的网站创建一个API接口的项目。接下来，你需要为你的应用程序启用GMAIL API。创建凭证，然后下载这些凭证，保存为credentials.json。

import pickle
import os.path
from googleapiclient.discovery import build
from google_auth_oauthlib.flow import InstalledAppFlow
from google.auth.transport.requests import Request

from email.mime.text import MIMEText
import base64

#pip install --upgrade google-api-python-client google-auth-httplib2 google-auth-oauthlib

# If modifying these scopes, delete the file token.pickle.
SCOPES = ['https://www.googleapis.com/auth/gmail.readonly', 'https://www.googleapis.com/auth/gmail.send']

def create_message(sender, to, subject, msg):
    message = MIMEText(msg)
    message['to'] = to
    message['from'] = sender
    message['subject'] = subject

    # Base 64 encode
    b64_bytes = base64.urlsafe_b64encode(message.as_bytes())
    b64_string = b64_bytes.decode()
    return {'raw': b64_string}
    #return {'raw': base64.urlsafe_b64encode(message.as_string())}

def send_message(service, user_id, message):
    #try:
    message = (service.users().messages().send(userId=user_id, body=message).execute())
    print( 'Message Id: %s' % message['id'] )
    return message
    #except errors.HttpError, error:print( 'An error occurred: %s' % error )

def main():
    """Shows basic usage of the Gmail API.
    Lists the user's Gmail labels.
    """
    creds = None
    # The file token.pickle stores the user's access and refresh tokens, and is
    # created automatically when the authorization flow completes for the first
    # time.
    if os.path.exists('token.pickle'):
        with open('token.pickle', 'rb') as token:
            creds = pickle.load(token)
    # If there are no (valid) credentials available, let the user log in.
    if not creds or not creds.valid:
        if creds and creds.expired and creds.refresh_token:
            creds.refresh(Request())
        else:
            flow = InstalledAppFlow.from_client_secrets_file(
                'credentials.json', SCOPES)
            creds = flow.run_local_server(port=0)
        # Save the credentials for the next run
        with open('token.pickle', 'wb') as token:
            pickle.dump(creds, token)

    service = build('gmail', 'v1', credentials=creds)

    # Example read operation
    results = service.users().labels().list(userId='me').execute()
    labels = results.get('labels', [])

    if not labels:
        print('No labels found.')
    else:
        print('Labels:')
    for label in labels:
        print(label['name'])

    # Example write
    msg = create_message("from@gmail.com", "to@gmail.com", "Subject", "Msg")
    send_message( service, 'me', msg)

if __name__ == '__main__':
    main()

def send_email(user, pwd, recipient, subject, body):
    import smtplib

    FROM = user
    TO = recipient if isinstance(recipient, list) else [recipient]
    SUBJECT = subject
    TEXT = body

    # Prepare actual message
    message = """From: %s\nTo: %s\nSubject: %s\n\n%s
    """ % (FROM, ", ".join(TO), SUBJECT, TEXT)
    try:
        server = smtplib.SMTP("smtp.gmail.com", 587)
        server.ehlo()
        server.starttls()
        server.login(user, pwd)
        server.sendmail(FROM, TO, message)
        server.close()
        print 'successfully sent the mail'
    except:
        print "failed to send mail"

如果你想使用端口465，你必须创建一个SMTP_SSL对象:

# SMTP_SSL Example
server_ssl = smtplib.SMTP_SSL("smtp.gmail.com", 465)
server_ssl.ehlo() # optional, called by login()
server_ssl.login(gmail_user, gmail_pwd)  
# ssl server doesn't support or need tls, so don't call server_ssl.starttls() 
server_ssl.sendmail(FROM, TO, message)
#server_ssl.quit()
server_ssl.close()
print 'successfully sent the mail'

在您的gmail帐户上启用不太安全的应用程序，并使用(Python>=3.6):

import smtplib
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText

gmailUser = 'XXXXX@gmail.com'
gmailPassword = 'XXXXX'
recipient = 'XXXXX@gmail.com'

message = f"""
Type your message here...
"""

msg = MIMEMultipart()
msg['From'] = f'"Your Name" <{gmailUser}>'
msg['To'] = recipient
msg['Subject'] = "Subject here..."
msg.attach(MIMEText(message))

try:
    mailServer = smtplib.SMTP('smtp.gmail.com', 587)
    mailServer.ehlo()
    mailServer.starttls()
    mailServer.ehlo()
    mailServer.login(gmailUser, gmailPassword)
    mailServer.sendmail(gmailUser, recipient, msg.as_string())
    mailServer.close()
    print ('Email sent!')
except:
    print ('Something went wrong...')

你同意OOP吗?

#!/usr/bin/env python


import smtplib

class Gmail(object):
    def __init__(self, email, password):
        self.email = email
        self.password = password
        self.server = 'smtp.gmail.com'
        self.port = 587
        session = smtplib.SMTP(self.server, self.port)        
        session.ehlo()
        session.starttls()
        session.ehlo
        session.login(self.email, self.password)
        self.session = session

    def send_message(self, subject, body):
        ''' This must be removed '''
        headers = [
            "From: " + self.email,
            "Subject: " + subject,
            "To: " + self.email,
            "MIME-Version: 1.0",
           "Content-Type: text/html"]
        headers = "\r\n".join(headers)
        self.session.sendmail(
            self.email,
            self.email,
            headers + "\r\n\r\n" + body)


gm = Gmail('Your Email', 'Password')

gm.send_message('Subject', 'Message')

import smtplib
server = smtplib.SMTP('smtp.gmail.com', 587)
server.ehlo()
server.starttls()
server.login("fromaddress", "password")
msg = "HI!"
server.sendmail("fromaddress", "receiveraddress", msg)
server.quit()

这是

创建Gmail APP密码!

创建之后，创建一个名为sendgmail.py的文件

然后添加以下代码:

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# =============================================================================
# Created By  : Jeromie Kirchoff
# Created Date: Mon Aug 02 17:46:00 PDT 2018
# =============================================================================
# Imports
# =============================================================================
import smtplib

# =============================================================================
# SET EMAIL LOGIN REQUIREMENTS
# =============================================================================
gmail_user = 'THEFROM@gmail.com'
gmail_app_password = 'YOUR-GOOGLE-APPLICATION-PASSWORD!!!!'

# =============================================================================
# SET THE INFO ABOUT THE SAID EMAIL
# =============================================================================
sent_from = gmail_user
sent_to = ['THE-TO@gmail.com', 'THE-TO@gmail.com']
sent_subject = "Hey Friends!"
sent_body = ("Hey, what's up? friend!\n\n"
             "I hope you have been well!\n"
             "\n"
             "Cheers,\n"
             "Jay\n")

email_text = """\
From: %s
To: %s
Subject: %s

%s
""" % (sent_from, ", ".join(sent_to), sent_subject, sent_body)

# =============================================================================
# SEND EMAIL OR DIE TRYING!!!
# Details: http://www.samlogic.net/articles/smtp-commands-reference.htm
# =============================================================================

try:
    server = smtplib.SMTP_SSL('smtp.gmail.com', 465)
    server.ehlo()
    server.login(gmail_user, gmail_app_password)
    server.sendmail(sent_from, sent_to, email_text)
    server.close()

    print('Email sent!')
except Exception as exception:
    print("Error: %s!\n\n" % exception)

所以，如果你成功了，你会看到这样的图像:

我通过给自己和自己发送电子邮件进行测试。

注意:我在我的帐户上启用了两步验证。应用程序密码与此工作!(对于gmail SMTP设置，您必须访问https://support.google.com/accounts/answer/185833?hl=en并遵循以下步骤) 此设置对于启用了两步验证的帐户不可用。这样的帐户需要特定于应用程序的密码来访问不太安全的应用程序。

澄清

导航到https://myaccount.google.com/apppasswords，并创建一个APP密码如上所述。