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

This was painful, but I seem to have something going now...

Python3 is not supported (yet)

I don't think it will be too hard to attain, as I was stumbling through converting packages without hitting anything massive: just the usual 2to3 stuff. Yet after a couple of hours I got tired of swimming upstream. At time of writing, I couldn't find a published package for public consumption for Python 3. The python 2 experience was straight-forward (in comparison).

Navigating the Google website is half the battle

No doubt, over time, this will change. Ultimately you need to download a client_secret.json file. You can only (probably) do this setting up stuff via a web browser:

1. You need a google account - either google apps or gmail. So, if you haven't got one, go get one.
2. Get yourself to the developers console
3. Create a new project, and wait 4 or 400 seconds for that to complete.
4. Navigate to API's and Auth -> Credentials
5. Under OAuth select Create New Client ID
6. Choose Installed Application as the application type and Other
7. You should now have a button Download JSON. Do that. It's your client_secret.json—the passwords so to speak

But wait that's not all!

You have to give your application a "Product Name" to avoid some odd errors. (see how much I suffered to give you this ;-)

1. Navigate to API's & auth -> Consent Screen
2. Choose your email
3. Enter a PRODUCT NAME. It doesn't matter what it is. "Foobar" will do fine.
4. Save

Newsflash! Whoa. Now there's even more!

1. Navigate to API's & auth -> APIs -> Gmail API
2. Click the button Enable API

Yay. Now we can update the emailing script.

Python 2

You need to run the script interactively the first time. It will open a web browser on your machine and you'll grant permissions (hit a button). This exercise will save a file to your computer gmail.storage which contains a reusable token.

[I had no luck transferring the token to a machine which has no graphical browser functionality—returns an HTTPError. I tried to get through it via the lynx graphical browser. That also failed because google have set the final "accept" button to "disabled"!? I'll raise another question to jump this hurdle (more grumbling)]

First you need some libraries:

pip install --upgrade google-api-python-clientpip install --upgrade python-gflags

• you need to change the to and from addresses
• make sure you have the client_token.json file whereever the Storage instructions expect it
• the directory needs to be writable so it can save the gmail.storage file

Finally some code:

import base64import httplib2from email.mime.text import MIMETextfrom apiclient.discovery import buildfrom oauth2client.client import flow_from_clientsecretsfrom oauth2client.file import Storagefrom oauth2client.tools import run# Path to the client_secret.json file downloaded from the Developer ConsoleCLIENT_SECRET_FILE = 'client_secret.json'# Check https://developers.google.com/gmail/api/auth/scopes for all available scopesOAUTH_SCOPE = 'https://www.googleapis.com/auth/gmail.compose'# Location of the credentials storage fileSTORAGE = Storage('gmail.storage')# Start the OAuth flow to retrieve credentialsflow = flow_from_clientsecrets(CLIENT_SECRET_FILE, scope=OAUTH_SCOPE)http = httplib2.Http()# Try to retrieve credentials from storage or run the flow to generate themcredentials = STORAGE.get()if credentials is None or credentials.invalid:  credentials = run(flow, STORAGE, http=http)# Authorize the httplib2.Http object with our credentialshttp = credentials.authorize(http)# Build the Gmail service from discoverygmail_service = build('gmail', 'v1', http=http)# create a message to sendmessage = MIMEText("Message goes here.")message['to'] = "yourvictim@goes.here"message['from'] = "you@go.here"message['subject'] = "your subject goes here"body = {'raw': base64.b64encode(message.as_string())}# send ittry:  message = (gmail_service.users().messages().send(userId="me", body=body).execute())  print('Message Id: %s' % message['id'])  print(message)except Exception as error:  print('An error occurred: %s' % error)

Hopefully that gets us all started. Not as simple as the old way, but does look a lot less complicated now I can see it in the flesh.

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 base64from email.mime.audio import MIMEAudiofrom email.mime.base import MIMEBasefrom email.mime.image import MIMEImagefrom email.mime.multipart import MIMEMultipartfrom email.mime.text import MIMETextimport mimetypesimport os#from __future__ import print_functionimport httplib2import osfrom apiclient import discoveryimport oauth2clientfrom oauth2client import clientfrom oauth2client import toolsfrom apiclient import errorsSCOPES = '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 = Nonedef 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' % errordef 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 credentialsif __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.

Updated sample for Python 3, and GMail's current API, below.

Note that to get the credentials.json file below, you'll need to create an Oauth client ID credential here, after selecting the relevant GCP project. Once you've created it you'll be shown the client key and client secret. Close that prompt, and click the down arrow next to the account. This is the file you'll need.

import base64import loggingimport mimetypesimport osimport os.pathimport picklefrom email.mime.text import MIMETextfrom google_auth_oauthlib.flow import InstalledAppFlowfrom google.auth.transport.requests import Requestfrom googleapiclient import errorsfrom googleapiclient.discovery import builddef get_service():    """Gets an authorized Gmail API service instance.    Returns:        An authorized Gmail API service instance..    """        # If modifying these scopes, delete the file token.pickle.    SCOPES = [        'https://www.googleapis.com/auth/gmail.readonly',        'https://www.googleapis.com/auth/gmail.send',    ]    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)    return servicedef send_message(service, sender, 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:    sent_message = (service.users().messages().send(userId=sender, body=message)               .execute())    logging.info('Message Id: %s', sent_message['id'])    return sent_message  except errors.HttpError as error:    logging.error('An HTTP error occurred: %s', error)def create_message(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  s = message.as_string()  b = base64.urlsafe_b64encode(s.encode('utf-8'))  return {'raw': b.decode('utf-8')}if __name__ == '__main__':    logging.basicConfig(        format="[%(levelname)s] %(message)s",        level=logging.INFO    )    try:        service = get_service()        message = create_message("from@gmail.com", "to@gmail.com", "Test subject", "Test body")        send_message(service, "from@gmail.com", message)    except Exception as e:        logging.error(e)        raise