187 lines
6.6 KiB
Python
187 lines
6.6 KiB
Python
"""图形验证码 & 滑块拼图验证码"""
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import random
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import string
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import io
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import hashlib
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import hmac
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import time
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import base64
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from typing import Tuple
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from PIL import Image, ImageDraw, ImageFont
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# ── HMAC 一次性 token ──────────────────────────────────
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_SECRET = hashlib.sha256(b"cma-captcha-secret-2024").digest()
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def sign_token(captcha_id: str, value: str) -> str:
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"""签发一次性 token"""
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ts = str(int(time.time()))
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msg = f"{captcha_id}:{value}:{ts}".encode()
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sig = hmac.new(_SECRET, msg, "sha256").hexdigest()[:12]
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return f"{captcha_id}.{value}.{ts}.{sig}"
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def verify_token(token: str, expected_value: str, max_age: int = 300) -> bool:
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"""验证一次性 token，防止重放"""
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try:
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parts = token.split(".")
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if len(parts) != 4:
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return False
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captcha_id, value, ts_str, sig = parts
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if value != expected_value:
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return False
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if int(time.time()) - int(ts_str) > max_age:
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return False
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expected_sig = hmac.new(
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_SECRET, f"{captcha_id}:{value}:{ts_str}".encode(), "sha256"
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).hexdigest()[:12]
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if sig != expected_sig:
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return False
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return True
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except (ValueError, IndexError):
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return False
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# ── 字体 ────────────────────────────────────────────────
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def _load_font(size: int) -> ImageFont.FreeTypeFont | ImageFont.ImageFont:
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"""优先使用中文字体，回退默认"""
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for p in [
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"/usr/share/fonts/opentype/noto/NotoSansCJKSC-VF.otf",
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"/usr/share/fonts/opentype/noto/NotoSansCJK-Regular.ttc",
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"/usr/share/fonts/truetype/wqy/wqy-zenhei.ttc",
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"/usr/share/fonts/truetype/dejavu/DejaVuSans-Bold.ttf",
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]:
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try:
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return ImageFont.truetype(p, size)
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except (IOError, OSError):
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continue
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return ImageFont.load_default()
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# ── 图形验证码（4位字母数字） ────────────────────────────
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def generate_image_captcha() -> Tuple[str, str, str]:
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"""
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返回: (captcha_id, plain_text, base64_png)
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仅需保持 captcha_id 与 plain_text 在 token 中绑定
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"""
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chars = string.ascii_uppercase + string.digits
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text = "".join(random.choices(chars, k=4))
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captcha_id = hashlib.md5(f"{time.time()}{random.random()}".encode()).hexdigest()[:16]
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w, h = 160, 60
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img = Image.new("RGB", (w, h), (255, 255, 255))
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draw = ImageDraw.Draw(img)
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font = _load_font(36)
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# 干扰线
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for _ in range(5):
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x1, y1 = random.randint(0, w // 2), random.randint(0, h)
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x2, y2 = random.randint(w // 2, w), random.randint(0, h)
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draw.line(
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[(x1, y1), (x2, y2)],
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fill=(random.randint(100, 200), random.randint(100, 200), random.randint(100, 200)),
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width=2,
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)
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# 噪点
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for _ in range(80):
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draw.point(
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(random.randint(0, w), random.randint(0, h)),
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fill=(random.randint(0, 255), random.randint(0, 255), random.randint(0, 255)),
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)
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# 文字
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x_offset = 12
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for ch in text:
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angle = random.randint(-25, 25)
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ch_img = Image.new("RGBA", (36, 48), (255, 255, 255, 0))
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ch_draw = ImageDraw.Draw(ch_img)
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ch_draw.text((2, -2), ch, fill=(random.randint(0, 80), random.randint(0, 80), random.randint(0, 80)), font=font)
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rotated = ch_img.rotate(angle, expand=True, fillcolor=(255, 255, 255, 0))
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img.paste(rotated, (x_offset, random.randint(5, 15)), rotated)
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x_offset += 34
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buf = io.BytesIO()
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img.save(buf, format="PNG")
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b64 = base64.b64encode(buf.getvalue()).decode()
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return captcha_id, text, f"data:image/png;base64,{b64}"
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# ── 滑块拼图验证码 ──────────────────────────────────────
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def generate_slider_captcha() -> Tuple[str, str, dict]:
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"""
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返回: (captcha_id, answer_xxx, {
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bg: base64 背景图,
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slice: base64 滑块拼图块,
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x: 缺口x坐标 (前端拼图用)
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})
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"""
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captcha_id = hashlib.md5(f"{time.time()}{random.random()}".encode()).hexdigest()[:16]
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bg_w, bg_h = 280, 160
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img = Image.new("RGB", (bg_w, bg_h), (240, 240, 240))
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draw = ImageDraw.Draw(img)
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# 背景色块
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for _ in range(3):
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r = random.randint(200, 255)
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g = random.randint(200, 255)
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b = random.randint(200, 255)
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x1, y1 = random.randint(0, bg_w - 60), random.randint(0, bg_h - 40)
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draw.rectangle([x1, y1, x1 + 60, y1 + 40], fill=(r, g, b))
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# 随机干扰线
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for _ in range(8):
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draw.line(
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[
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(random.randint(0, bg_w), random.randint(0, bg_h)),
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(random.randint(0, bg_w), random.randint(0, bg_h)),
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],
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fill=(random.randint(180, 220), random.randint(180, 220), random.randint(180, 220)),
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width=1,
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)
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# 随机绘制文字（增加OCR难度）
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font_small = _load_font(14)
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for _ in range(12):
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x = random.randint(0, bg_w - 30)
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y = random.randint(0, bg_h - 20)
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c = random.choice(string.ascii_uppercase)
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draw.text((x, y), c, fill=(random.randint(150, 220), random.randint(150, 220), random.randint(150, 220)), font=font_small)
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# 缺口位置
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gap_size = 40
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gap_x = random.randint(20, bg_w - gap_size - 20)
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gap_y = random.randint(15, bg_h - gap_size - 15)
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# 在背景图上切出缺口（深色填充）
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draw.rectangle([gap_x, gap_y, gap_x + gap_size, gap_y + gap_size], fill=(80, 80, 80))
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# 创建滑块拼图块（从另一位置裁取）
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slice_x = max(0, gap_x - 80)
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if slice_x + gap_size > bg_w:
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slice_x = bg_w - gap_size - 10
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slice_img = img.crop((slice_x, gap_y, slice_x + gap_size, gap_y + gap_size))
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# 给滑块块加白色边框
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slice_with_border = Image.new("RGB", (gap_size + 4, gap_size + 4), (255, 255, 255))
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slice_with_border.paste(slice_img, (2, 2))
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buf_bg = io.BytesIO()
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img.save(buf_bg, format="PNG")
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bg_b64 = base64.b64encode(buf_bg.getvalue()).decode()
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buf_slice = io.BytesIO()
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slice_with_border.save(buf_slice, format="PNG")
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slice_b64 = base64.b64encode(buf_slice.getvalue()).decode()
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# answer 存 gap_x 的字符串形式
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answer = hashlib.md5(str(gap_x).encode()).hexdigest()[:16]
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return captcha_id, f"ans_{answer}", {
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"bg": f"data:image/png;base64,{bg_b64}",
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"slice": f"data:image/png;base64,{slice_b64}",
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"gap_x": gap_x,
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}
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