Python Flask implementation of the image verification code and e-mail verification code process explained in detail

import random
import string
from io import BytesIO
from PIL import Image, ImageFont, ImageDraw
class ImageCode:
    def rand_color(self):
        """Generate random colors for drawing strings(You can specify as much as you want.0-255number between)"""
        red = (32, 200)
        green = (22, 255)
        blue = (0, 200)
        return red, green, blue
    def gen_text(self):
        """Generate a 4-digit random string."""
        # sample is used to construct a sub-list of N random characters from a large list or string.
        list = (string.ascii_letters, 5)
        return ''.join(list)
    def draw_verify_code(self):
        """Drawing CAPTCHA images."""
        code = self.gen_text()
        width, height = 120, 50  # Set the image size, which can be adjusted according to actual needs
        im = ('RGB', (width, height), 'white')  # Create a picture object and set the background color to white
        font = (font='', size=40)  # Choose which font and font size to use
        draw = (im)  # New ImageDraw object
        # Draw strings
        for i in range(4):
            ((5 + (-3, 3) + 23 * i, 5 + (-3, 3)),
                      text=code[i], fill=self.rand_color(), font=font)
        ()

ImageCode().draw_verify_code()

def draw_lines(self, draw, num, width, height):
    """
    Drawing interference lines
    :param draw: picture object
    :param num: number of interference lines
    :param width: width of the picture
    :param height: height of the image
    :return.
    """
    for num in range(num):
        x1 = (0, width / 2)
        y1 = (0, height / 2)
        x2 = (0, width)
        y2 = (height / 2, height)
        (((x1, y1), (x2, y2)), fill='black', width=2)

def draw_verify_code(self):
    """Drawing CAPTCHA images."""
    code = self.gen_text()
    width, height = 120, 50  # Set the image size, which can be adjusted according to actual needs
    im = ('RGB', (width, height), 'white')  # Create a picture object and set the background color to white
    font = (font='', size=40)  # Choose which font and font size to use
    draw = (im)  # New ImageDraw object
    # Draw strings
    for i in range(4):
        ((5 + (-3, 3) + 23 * i, 5 + (-3, 3)),text=code[i], fill=self.rand_color(), font=font)
    self.draw_lines(draw, 4, width, height)  # Drawing interference lines
    ()

def draw_verify_code(self):
    """Drawing CAPTCHA images."""
    code = self.gen_text()
    width, height = 120, 50  # Set the image size, which can be adjusted according to actual needs
    im = ('RGB', (width, height), 'white')  # Create a picture object and set the background color to white
    font = (font='', size=40)  # Choose which font and font size to use
    draw = (im)  # New ImageDraw object
    # Draw strings
    for i in range(4):
        ((5 + (-3, 3) + 23 * i, 5 +(-3, 3)), text=code[i], fill=self.rand_color(), font=font)
        self.draw_lines(draw, 4, width, height)  # Drawing interference lines
    # () # For temporary debugging, you can display the generated image directly
    return im, code

from flask import Blueprint, make_response, session
from  import ImageCode
from  import Users
user = Blueprint('user', __name__)
@('/vcode')
def vcode():
    code, bstring = ImageCode().get_code()
    response = make_response(bstring)
    ['Content-Type'] = 'image/jpeg'
    session['vcode'] = ()
    return response

if __name__ == '__main__':
    from  import *
    app.register_blueprint(user)
    (debug=True)  # have sth. in placedebugmode of operation

<img src="/vcode" style="cursor:pointer;"/>

<img src="/vcode"  class="col-3" style="cursor:pointer;" onclick="='/vcode?'+()"/>

from smtplib import SMTP_SSL
from  import MIMEText
from  import Header
def send_email(self, receiver, ecode):
    """Send mail."""
    sender = 'XXX <xxxxxxxxx@>'  # E-mail account number and sender's signature
    # Define the content of the email to be sent, with support for HTML and CSS styles
    content = f"Your email verification code is：<span style='color: red; font-size: 20px;'>{ecode}</span>" 
    message = MIMEText(content, 'html', 'utf-8')  # Instantiate the mail object and specify the key message of the message
    # Specify the subject of the message, again using utf-8 encoding
    message['Subject'] = Header('CAPTCHA', 'utf-8')
    message['From'] = sender
    message['To'] = receiver
    smtpObj = SMTP_SSL('')  # Links to QQ mail servers
    (user='xxxxxxxxx@', password='Authorization Code')  # Login to QQ mailbox through your own mailbox account and the obtained authorization code
    # Specify the sender, recipient and content of the message
    (sender, receiver, str(message))
    ()
def gen_email_code(self):
    str = (string.ascii_letters + , 6)
    return ''.join(str)

@('/ecode', methods=['POST'])
def ecode():
    email = ('email')
	# Formatting mailboxes
    if not ('^.+\\@(\\[?)[a-zA-Z0-9\\-\\.]+\\.([a-zA-Z]{2,3}|[0-9]{1,3})(\\]?)$', email):
        return 'email-invalid'
    code = gen_email_code()
    try:
        send_email(email, code)
        session['ecode'] = code  # Save email verification code in session
        return 'send-pass'
    except:
        return 'send-fail'