app/services/image_proxy_service.py

# app/services/image_proxy_service.py

import logging
import base64
import httpx
import asyncio # 导入 asyncio 模块
from fastapi import Request, HTTPException
from fastapi.responses import StreamingResponse, JSONResponse, Response # 导入 Response 类
from typing import Optional, Tuple

# 导入自定义模块
from app.core.gemini_client_manager import get_next_gemini_cookie_tuple # 从 core 模块导入获取 cookie 的函数

logger = logging.getLogger(__name__)

# 定义需要跳过后端下载的域名，这些域名的图片将通过代理加载
SKIP_DOWNLOAD_DOMAINS = ["googleusercontent.com", "blogger.googleusercontent.com", "lh3.googleusercontent.com"]

async def proxy_image_request(image_url: str, request: Request):
    """
    代理图片下载，解决前端跨域或防盗链问题。
    """
    logger.info(f"接收到图片代理请求: {image_url}")
    
    # 获取下一组Gemini Cookie
    cookie_tuple: Optional[Tuple[str, str]] = get_next_gemini_cookie_tuple()
    cookies = {}
    if cookie_tuple:
        sid, sidts = cookie_tuple
        cookies = {
            "__Secure-1PSID": sid,
            "__Secure-1PSIDTS": sidts
        }
        logger.info(f"使用Cookie代理图片下载: sid={sid[:5]}..., sidts={sidts[:5]}...")
    
    # 设置更安全的请求头
    headers = {
        "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36",
        "Accept": "image/webp,image/apng,image/*,*/*;q=0.8",
        "Accept-Language": "en-US,en;q=0.9",
        "Referer": "https://gemini.google.com/",
        "Sec-Fetch-Dest": "image",
        "Sec-Fetch-Mode": "no-cors",
        "Sec-Fetch-Site": "same-origin",
    }
    
    max_retries = 3
    retry_delay = 1.0  # 重试间隔（秒）
    
    for attempt in range(max_retries):
        try:
            async with httpx.AsyncClient(
                follow_redirects=True, 
                trust_env=False,
                max_redirects=5,
                cookies=cookies,
                http2=True
            ) as client:
                # 添加详细日志
                logger.debug(f"开始代理下载图片 (尝试 {attempt+1}/{max_retries}): {image_url}")
                response = await client.get(image_url, timeout=30, headers=headers)
                response.raise_for_status()
                
                # 记录响应详情
                logger.info(f"图片代理成功: URL={image_url}, 状态码={response.status_code}, 类型={response.headers.get('Content-Type')}")
                
                # 返回流式响应
                return StreamingResponse(
                    content=response.iter_bytes(),
                    media_type=response.headers.get("Content-Type", "image/jpeg"),
                    headers={
                        "Cache-Control": "public, max-age=86400",  # 缓存一天
                        "Access-Control-Allow-Origin": "*"
                    }
                )
        except httpx.HTTPStatusError as e:
            if attempt == max_retries - 1:
                logger.error(f"代理下载图片失败: URL: {image_url}, 状态码: {e.response.status_code}")
                # 返回一个透明的 1x1 像素 GIF 图片作为占位符
                transparent_gif_base64 = "R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7"
                transparent_gif_bytes = base64.b64decode(transparent_gif_base64)
                return Response(
                    content=transparent_gif_bytes,
                    media_type="image/gif",
                    headers={
                        "Cache-Control": "public, max-age=60",  # 短时间缓存
                        "Access-Control-Allow-Origin": "*"  # 允许跨域
                    }
                )
            logger.warning(f"尝试 {attempt+1}/{max_retries} 失败，状态码: {e.response.status_code}")
        except httpx.TooManyRedirects:
            if attempt == max_retries - 1:
                logger.error(f"代理下载图片重定向过多: URL: {image_url}")
                # 返回一个透明的 1x1 像素 GIF 图片作为占位符
                transparent_gif_base64 = "R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7"
                transparent_gif_bytes = base64.b64decode(transparent_gif_base64)
                return Response(
                    content=transparent_gif_bytes,
                    media_type="image/gif",
                    headers={
                        "Cache-Control": "public, max-age=60",  # 短时间缓存
                        "Access-Control-Allow-Origin": "*"  # 允许跨域
                    }
                )
            logger.warning(f"尝试 {attempt+1}/{max_retries} 失败: 重定向过多")
        except (httpx.RequestError, Exception) as e:
            if attempt == max_retries - 1:
                logger.error(f"代理下载图片失败: URL: {image_url}, 错误: {type(e).__name__} - {e}")
                # 返回一个透明的 1x1 像素 GIF 图片作为占位符
                transparent_gif_base64 = "R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7"
                transparent_gif_bytes = base64.b64decode(transparent_gif_base64)
                return Response(
                    content=transparent_gif_bytes,
                    media_type="image/gif",
                    headers={
                        "Cache-Control": "public, max-age=60",  # 短时间缓存
                        "Access-Control-Allow-Origin": "*"  # 允许跨域
                    }
                )
            logger.warning(f"尝试 {attempt+1}/{max_retries} 失败: {type(e).__name__} - {e}")
        
        # 等待一段时间后重试
        await asyncio.sleep(retry_delay * (attempt + 1))