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FastapiAdmin/backend/app/utils/captcha_util.py
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zhangtao b0ae6af3b1 chore: update .gitignore and enhance docstrings across multiple files
- Added *.pyc and *.pyo to .gitignore to prevent compiled Python files from being tracked.
- Improved docstrings in various modules, providing clearer descriptions of functions, parameters, and return values to enhance code readability and maintainability.
2026-04-04 01:21:59 +08:00

139 lines
5.0 KiB
Python

import base64
import random
import string
from io import BytesIO
from PIL import Image, ImageDraw, ImageFont
from app.config.setting import settings
class CaptchaUtil:
"""
验证码工具类
"""
@classmethod
def generate_captcha(cls) -> tuple[str, str]:
"""
生成带有噪声和干扰的验证码图片(4位随机字符)。
返回:
- tuple[str, str]: Base64 PNG 字符串与验证码明文。
"""
# 生成4位随机验证码
chars = string.digits + string.ascii_letters
captcha_value = "".join(random.sample(chars, 4))
# 创建一张随机颜色背景的图片
width, height = 160, 60
background_color = tuple(random.randint(230, 255) for _ in range(3))
image = Image.new("RGB", (width, height), color=background_color)
draw = ImageDraw.Draw(image)
# 使用指定字体
font = ImageFont.truetype(font=settings.CAPTCHA_FONT_PATH, size=settings.CAPTCHA_FONT_SIZE)
# 计算文本总宽度和高度
total_width = sum(draw.textbbox((0, 0), char, font=font)[2] for char in captcha_value)
text_height = draw.textbbox((0, 0), captcha_value[0], font=font)[3]
# 计算起始位置,使文字居中
x_start = (width - total_width) / 2
y_start = (height - text_height) / 2 - draw.textbbox((0, 0), captcha_value[0], font=font)[1]
# 绘制字符
x = x_start
for char in captcha_value:
# 使用深色文字,增加对比度
text_color = tuple(random.randint(0, 80) for _ in range(3))
# 随机偏移,增加干扰
x_offset = x + random.uniform(-2, 2)
y_offset = y_start + random.uniform(-2, 2)
# 绘制字符
draw.text((x_offset, y_offset), char, font=font, fill=text_color)
# 更新x坐标,增加字符间距的随机性
x += draw.textbbox((0, 0), char, font=font)[2] + random.uniform(1, 5)
# 添加干扰线
for _ in range(4):
line_color = tuple(random.randint(150, 200) for _ in range(3))
points = [(i, int(random.uniform(0, height))) for i in range(0, width, 20)]
draw.line(points, fill=line_color, width=1)
# 添加随机噪点
for _ in range(width * height // 60):
point_color = tuple(random.randint(0, 255) for _ in range(3))
draw.point(
(random.randint(0, width), random.randint(0, height)),
fill=point_color,
)
# 将图像数据保存到内存中并转换为base64
buffer = BytesIO()
image.save(buffer, format="PNG", optimize=True)
base64_string = base64.b64encode(buffer.getvalue()).decode()
return base64_string, captcha_value
@classmethod
def captcha_arithmetic(cls, difficulty: str = "medium") -> tuple[str, int]:
"""
创建算术验证码图片(加减乘运算);浅色底、居中算式,无旋转与干扰线/噪点。
参数:
- difficulty (str): 难度级别(easy / medium / hard),控制数字范围与可用运算符。
返回:
- tuple[str, int]: base64 编码的 PNG 图片字符串与正确答案(整数)。
"""
difficulty_config = {
"easy": {"num_range": (1, 9), "operators": ["+", "-"]},
"medium": {"num_range": (1, 15), "operators": ["+", "-", "*"]},
"hard": {"num_range": (1, 20), "operators": ["+", "-", "*"]},
}
config = difficulty_config.get(difficulty, difficulty_config["medium"])
operators = config["operators"]
operator = random.choice(operators)
num_range = config["num_range"]
if operator == "-":
num1 = random.randint(num_range[0] + 5, num_range[1])
num2 = random.randint(num_range[0], num1 - 1)
elif operator == "*":
num1 = random.randint(num_range[0], min(10, num_range[1]))
num2 = random.randint(num_range[0], min(10, num_range[1]))
else:
num1 = random.randint(num_range[0], num_range[1])
num2 = random.randint(num_range[0], num_range[1])
result_map = {
"+": lambda x, y: x + y,
"-": lambda x, y: x - y,
"*": lambda x, y: x * y,
}
captcha_value = result_map[operator](num1, num2)
width, height = 160, 60
image = Image.new("RGB", (width, height), color=(248, 249, 250))
draw = ImageDraw.Draw(image)
font = ImageFont.truetype(font=settings.CAPTCHA_FONT_PATH, size=settings.CAPTCHA_FONT_SIZE)
text = f"{num1} {operator} {num2} = ?"
tb = draw.textbbox((0, 0), text, font=font)
tw, th = tb[2] - tb[0], tb[3] - tb[1]
x = (width - tw) // 2
y = (height - th) // 2 - tb[1]
draw.text((x, y), text, fill=(55, 65, 81), font=font)
buffer = BytesIO()
image.save(buffer, format="PNG", optimize=True)
base64_string = base64.b64encode(buffer.getvalue()).decode()
return base64_string, captcha_value