基于Python+Flask实现一个简易网页验证码登录系统案例

pip install flask Pillow

from PIL import Image, ImageDraw, ImageFont
import random
import string
def generate_captcha_image():
    # 定义图片大小及背景颜色
    image = Image.new('RGB', (120, 30), color=(73, 109, 137))
    # 使用系统自带字体，或指定字体文件路径
    font_path = "./arial.ttf"
    fnt = ImageFont.truetype(font_path, 15)
    d = ImageDraw.Draw(image)
    # 生成5位数的验证码文本
    captcha_text = ''.join(random.choices(string.ascii_uppercase + string.digits, k=5))
    d.text((10, 10), captcha_text, font=fnt, fill=(255, 255, 0))
    # 添加干扰线条和噪点
    for _ in range(random.randint(3, 5)):
        start = (random.randint(0, image.width), random.randint(0, image.height))
        end = (random.randint(0, image.width), random.randint(0, image.height))
        d.line([start, end], fill=(random.randint(50, 200), random.randint(50, 200), random.randint(50, 200)))
    for _ in range(100):
        xy = (random.randrange(0, image.width), random.randrange(0, image.height))
        d.point(xy, fill=(random.randint(50, 200), random.randint(50, 200), random.randint(50, 200)))
    return image, captcha_text

from flask import Flask, render_template, jsonify, request, session
import io
app = Flask(__name__)
app.config['SECRET_KEY'] = 'your_secret_key_here'
@app.route('/')
def index():
    # 渲染登录页面
    return render_template('login.html')
@app.route('/captcha')
def captcha():
    # 使用上述函数生成验证码图片
    image, captcha_text = generate_captcha_image()
    # 将验证码文本存储到session，以便之后进行验证
    session['captcha'] = captcha_text
    buf = io.BytesIO()
    image.save(buf, format='PNG')
    buf.seek(0)
    return buf.getvalue(), 200, {
        'Content-Type': 'image/png',
        'Content-Length': str(len(buf.getvalue()))
    }

@app.route('/login', methods=['POST'])
def login():
    # 检查用户输入的验证码是否与session中的一致
    if request.json.get('captcha', '').upper() == session.get('captcha', '').upper():
        return jsonify({'status': 'success', 'message': '登录成功'})
    else:
        return jsonify({'status': 'error', 'message': '验证码错误'}), 400