Method get_file_response

core/storage.py:316–382

(self, file_code: FileCodes)

            )

    async def get_file_response(self, file_code: FileCodes):
        try:
            filename = file_code.prefix + file_code.suffix
            content_length = None  # 初始化为 None，表示未知大小
            
            async with self._client() as s3:
                # 尝试获取文件大小（HEAD请求）
                try:
                    head_response = await s3.head_object(
                        Bucket=self.bucket_name,
                        Key=await file_code.get_file_path()
                    )
                    # 从HEAD响应中获取Content-Length
                    if 'ContentLength' in head_response:
                        content_length = head_response['ContentLength']
                    elif 'Content-Length' in head_response['ResponseMetadata']['HTTPHeaders']:
                        content_length = int(head_response['ResponseMetadata']['HTTPHeaders']['Content-Length'])
                except Exception:
                    # 如果HEAD请求失败，则不提供 Content-Length
                    pass
                
                link = await s3.generate_presigned_url(
                    "get_object",
                    Params={
                        "Bucket": self.bucket_name,
                        "Key": await file_code.get_file_path(),
                    },
                    ExpiresIn=3600,
                )
            
            # 创建ClientSession并传递给生成器复用
            session = aiohttp.ClientSession()
            
            async def stream_generator():
                try:
                    async with session.get(link) as resp:
                        if resp.status != 200:
                            raise HTTPException(
                                status_code=resp.status,
                                detail=f"从S3获取文件失败: {resp.status}"
                            )
                        # 设置块大小（例如64KB）
                        chunk_size = 65536
                        while True:
                            chunk = await resp.content.read(chunk_size)
                            if not chunk:
                                break
                            yield chunk
                finally:
                    await session.close()
            
            from fastapi.responses import StreamingResponse
            encoded_filename = quote(filename, safe='')
            headers = {
                "Content-Disposition": f"attachment; filename*=UTF-8''{encoded_filename}"
            }
            if content_length is not None:
                headers["Content-Length"] = str(content_length)