feat(auth): 添加验证码功能以增强登录安全性

实现验证码生成、存储和验证逻辑
- 新增验证码生成工具函数
- 在登录接口中添加验证码校验
- 添加获取验证码图片的API端点
- 更新用户登录schema包含验证码字段
- 添加captcha依赖到requirements.txt

backend/.trae/rules/git-commit-message.md

@@ -0,0 +1,6 @@
+---
+alwaysApply: true
+scene: git_message
+---
+
+在此处编写规则，自定义 AI 生成提交信息的风格。

backend/auth/apps/users/urls.py

@@ -1,4 +1,5 @@
 from fastapi import APIRouter, Depends, HTTPException, status
+from fastapi.responses import Response
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy import select
 from fastcrud import FastCRUD
@@ -19,6 +20,7 @@ from utils.password import verify_password, get_password_hash
 from utils.jwt import create_access_token
 from config import app_settings
 from utils.redis_client import get_redis, set_token_in_redis
+from utils.captcha import create_captcha, validate_captcha
 from middleware import get_current_user
 
 router = APIRouter(prefix="/users", tags=["users"])
@@ -27,6 +29,19 @@ router = APIRouter(prefix="/users", tags=["users"])
 user_crud = FastCRUD(User, UserResponse)
 
 
+@router.get("/captcha")
+async def get_captcha(redis_conn: redis.Redis = Depends(get_redis)):
+    """获取验证码图片"""
+    # 创建验证码
+    captcha_id, image_bytes = await create_captcha(redis_conn)
+    
+    # 返回验证码图片，同时在响应头中返回验证码ID
+    response = Response(content=image_bytes, media_type="image/png")
+    response.headers["X-Captcha-ID"] = captcha_id
+    
+    return response
+
+
 @router.post("/login", response_model=Token)
 async def login(
     user_data: UserLogin,
@@ -34,6 +49,17 @@ async def login(
     redis_conn: redis.Redis = Depends(get_redis),
 ):
     """用户登录"""
+    # 验证验证码
+    is_captcha_valid = await validate_captcha(
+        redis_conn, user_data.captcha_id, user_data.captcha_code
+    )
+    if not is_captcha_valid:
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="验证码错误或已过期",
+            headers={"WWW-Authenticate": "Bearer"},
+        )
+
     # 查找用户
     result = await db.execute(select(User).filter(User.username == user_data.username))
     user = result.scalar_one_or_none()

backend/auth/requirements.txt

@@ -26,3 +26,6 @@ asyncpg>=0.31.0
 
 # Redis异步客户端
 redis>=7.2.0
+
+# 验证码生成
+captcha>=0.7.1

backend/auth/schemas.py

@@ -47,6 +47,8 @@ class UserLogin(BaseModel):
 
     username: str = Field(..., description="登录名")
     password: str = Field(..., description="密码")
+    captcha_id: str = Field(..., description="验证码ID")
+    captcha_code: str = Field(..., description="验证码")
 
 
 class UserResponse(BaseModel):

backend/auth/utils/captcha.py

@@ -0,0 +1,69 @@
+from io import BytesIO
+from captcha.image import ImageCaptcha
+from uuid import uuid4
+from utils.redis_client import get_redis, set_token_in_redis
+import redis.asyncio as redis
+import random
+import string
+
+
+def generate_captcha(length: int = 4) -> tuple[str, bytes]:
+    """生成验证码图片和验证码文本"""
+    # 生成随机验证码
+    characters = string.digits + string.ascii_uppercase
+    captcha_text = ''.join(random.choices(characters, k=length))
+    
+    # 生成验证码图片
+    image = ImageCaptcha(width=150, height=50)
+    image_bytes = image.generate(captcha_text)
+    
+    # 将图片转换为字节流
+    buffer = BytesIO()
+    buffer.write(image_bytes.read())
+    buffer.seek(0)
+    
+    return captcha_text, buffer.getvalue()
+
+
+async def save_captcha_to_redis(redis_conn: redis.Redis, captcha_id: str, captcha_text: str, expire_seconds: int = 300):
+    """将验证码保存到Redis"""
+    await redis_conn.set(f"captcha:{captcha_id}", captcha_text, ex=expire_seconds)
+
+
+async def get_captcha_from_redis(redis_conn: redis.Redis, captcha_id: str) -> str | None:
+    """从Redis获取验证码"""
+    return await redis_conn.get(f"captcha:{captcha_id}")
+
+
+async def delete_captcha_from_redis(redis_conn: redis.Redis, captcha_id: str):
+    """从Redis删除验证码"""
+    await redis_conn.delete(f"captcha:{captcha_id}")
+
+
+async def validate_captcha(redis_conn: redis.Redis, captcha_id: str, user_input: str) -> bool:
+    """验证验证码是否正确"""
+    stored_captcha = await get_captcha_from_redis(redis_conn, captcha_id)
+    if not stored_captcha:
+        return False
+    
+    # 忽略大小写比较
+    is_valid = stored_captcha.upper() == user_input.upper()
+    
+    # 无论验证成功与否，都删除验证码（防止重复使用）
+    await delete_captcha_from_redis(redis_conn, captcha_id)
+    
+    return is_valid
+
+
+async def create_captcha(redis_conn: redis.Redis) -> tuple[str, bytes]:
+    """创建验证码并保存到Redis"""
+    # 生成验证码
+    captcha_text, image_bytes = generate_captcha()
+    
+    # 生成唯一ID
+    captcha_id = str(uuid4())
+    
+    # 保存到Redis，有效期5分钟
+    await save_captcha_to_redis(redis_conn, captcha_id, captcha_text, 300)
+    
+    return captcha_id, image_bytes