One way to send emails is by using third-party APIs. Another way is to connect to the SMTP server directly. This is the second approach here.
Import the required libraries.
import smtplib from email.mime.text import MIMEText from email.mime.multipart import MIMEMultipart import email.utils as utils import time import ssl from cryptography.fernet import Fernet from urllib.parse import quote, unquote from datetime import datetime import html2text Create the EmailSenderclass.
Create __init__ and connectmethods as below.
class EmailSender: def __init__(self): self.smtp_server = "IP or DNS of SMTP Server" self.smtp_port = PORT HERE. Probabily 587 self.username = "USERNAME" self.password = "PASSWORD" self.sender_name = "ANURAG RANA" self.sender_address = "admin@anuragrana.in" self.domain = "http://anuragrana.in" self.smtp_connection = None def connect(self): if not self.smtp_connection: # this line below takes the most time self.smtp_connection = smtplib.SMTP(self.smtp_server, self.smtp_port) # Create a secure SSL context context = ssl.create_default_context() # self.smtp_connection.starttls(context=context) # might generate SSL error self.smtp_connection.starttls() self.smtp_connection.login(self.username, self.password) Add send method to this class to send the email.
def send_email(self, to_address, subject, body_html): msg = MIMEMultipart("alternative") msg['message-id'] = utils.make_msgid(domain=self.domain) print(msg['message-id']) msg["Subject"] = subject msg["From"] = f"{self.sender_name} <{self.sender_address}>" msg["To"] = to_address # Attach the body of the email - text plain text_content = html2text.html2text(body_html) msg.attach(MIMEText(text_content, "plain")) # Attach the body of the email - html msg.attach(MIMEText(body_html, "html")) # Add the List-Unsubscribe header msg.add_header('List-Unsubscribe', unsubscribe_url) msg["Date"] = utils.formatdate(localtime=True) try: response = self.smtp_connection.sendmail(self.sender_address, to_address, msg.as_string()) print(response) except Exception as e: print(e) Important: message-id, List-Unsubscribe, and Date are three headers that are required for better deliverability. Without these headers, your email score will be low. A low email score might lead your email to the spam folder.
MIMEMultipart(“alternative”): This is a subtype of the multipart content type. Using “alternative” indicates that the email message contains multiple representations of the same content, but in different formats. For example, you might have the same email message in both plain text and HTML. The recipient’s email client can then choose which one to display, usually the last part that the client understands. This is useful for ensuring that the recipient can read the email regardless of whether their email client supports plain text or HTML.
Finally, add the close-connection method to the above class.
# close the connection def close_connection(self): if self.smtp_connection: self.smtp_connection.quit() self.smtp_connection = None Now in the main code, perform the below steps to send the emails.
Initialize the EmailSender class and call the connect method to create a connection with the SMTP server.
email_sender = EmailSender() email_sender.connect() Create an Email Template in an HTML file. Read the content of this file in a variable.
# Read the content of the HTML file with open("templates/my-first-email-template.html", "r", encoding="utf-8") as file: body = file.read() Create the list of recipients. Let’s call it batch. Iterate over this batch to send emails to everyone individually.
batch = [] # current_batch text file contains email, one email in each line with open("current_batch.txt", 'r') as file: batch = file.readlines() Now send the emails.
for recipient in batch: # sleep for few seconds before each email to avoid flooding the recepient's inbox time.sleep(5) if not recipient or not recipient.strip(): continue recipient = recipient.strip() # check if recipient is in bouncelog if recipient in bounced: print(f'email in bouncelog. {recipient}') continue email_sender.send_email(recipient, subject, body) print(f'Mail sent to {recipient} - {time.time()}') We will discuss the bounce log and how to parse the POSTFIX logs for bounced emails in another article.
Connect with me if you want to set up a fully functional new email Postfix SMTP server to send and receive emails.
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Top comments (1)
booo ... It doesn't help. Try to include the configuration main.cf SMTP Postfix, and what are the arguments in the python code to connect to the postfix