How to send an email through gmail without enabling 'insecure access'?

Question

Google are pushing us to improve the security of script access to their gmail smtp servers. I have no problem with that. In fact I\'m happy to help.

But they\'re n

Answer 1

It seems that John Mee's answer is out of date. It does not work in July, 2016. Maybe due to the update of Gmail's API. I update his code (python 2) as below:

    """Send an email message from the user's account.
"""

import base64
from email.mime.audio import MIMEAudio
from email.mime.base import MIMEBase
from email.mime.image import MIMEImage
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
import mimetypes
import os

#from __future__ import print_function
import httplib2
import os

from apiclient import discovery
import oauth2client
from oauth2client import client
from oauth2client import tools

from apiclient import errors

SCOPES = 'https://www.googleapis.com/auth/gmail.compose'
CLIENT_SECRET_FILE = 'client_secret.json'
APPLICATION_NAME = 'Gmail API Python Quickstart'

try:
    import argparse
    flags = argparse.ArgumentParser(parents=[tools.argparser]).parse_args()
except ImportError:
    flags = None

def SendMessage(service, user_id, message):
  """Send an email message.

  Args:
    service: Authorized Gmail API service instance.
    user_id: User's email address. The special value "me"
    can be used to indicate the authenticated user.
    message: Message to be sent.

  Returns:
    Sent 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 CreateMessage(sender, to, subject, message_text):
  """Create a message for an email.

  Args:
    sender: Email address of the sender.
    to: Email address of the receiver.
    subject: The subject of the email message.
    message_text: The text of the email message.

  Returns:
    An object containing a base64url encoded email object.
  """
  message = MIMEText(message_text)
  message['to'] = to
  message['from'] = sender
  message['subject'] = subject
  return {'raw': base64.urlsafe_b64encode(message.as_string())}


def get_credentials():
    """Gets valid user credentials from storage.

    If nothing has been stored, or if the stored credentials are invalid,
    the OAuth2 flow is completed to obtain the new credentials.

    Returns:
        Credentials, the obtained credential.
    """
    home_dir = os.path.expanduser('~')
    credential_dir = os.path.join(home_dir, '.credentials')
    if not os.path.exists(credential_dir):
        os.makedirs(credential_dir)
    credential_path = os.path.join(credential_dir,
                                   'sendEmail.json')

    store = oauth2client.file.Storage(credential_path)
    credentials = store.get()
    if not credentials or credentials.invalid:
        flow = client.flow_from_clientsecrets(CLIENT_SECRET_FILE, SCOPES)
        flow.user_agent = APPLICATION_NAME
        if flags:
            credentials = tools.run_flow(flow, store, flags)
        else: # Needed only for compatibility with Python 2.6
            credentials = tools.run(flow, store)
        print('Storing credentials to ' + credential_path)
    return credentials

if __name__ == "__main__":

    try:
        credentials = get_credentials()
        http = credentials.authorize(httplib2.Http())
        service = discovery.build('gmail', 'v1', http=http)
        SendMessage(service, "me", CreateMessage("send@gmail.com", "receive@gmail.com", "Test gmail automation", "Hello world"))

    except Exception, e:
        print e
        raise

Note that if you encounter the error Insufficient Permission, one possible reason is that the scope in program is not set correctly. The other possible reason may be that you need to delete the storage json file ("sendEmail.json" in this program) and refresh your program. More details may be seen in this post.