gemini-balance/app/services/gemini_chat_service.py

# app/services/chat_service.py

import json
from typing import Dict, Any, AsyncGenerator, List
from app.core.logger import get_gemini_logger
from app.services.chat.api_client import GeminiApiClient
from app.services.chat.stream_optimizer import gemini_optimizer
from app.schemas.gemini_models import GeminiRequest
from app.core.config import settings
from app.services.chat.response_handler import GeminiResponseHandler
from app.services.key_manager import KeyManager

logger = get_gemini_logger()


def _has_image_parts(contents: List[Dict[str, Any]]) -> bool:
    """判断消息是否包含图片部分"""
    for content in contents:
        if "parts" in content:
            for part in content["parts"]:
                if "image_url" in part or "inline_data" in part:
                    return True
    return False


def _build_tools(model: str, payload: Dict[str, Any]) -> List[Dict[str, Any]]:
    """构建工具"""
    tools = []
    if settings.TOOLS_CODE_EXECUTION_ENABLED and not (
            model.endswith("-search") or "-thinking" in model
    ) and not _has_image_parts(payload.get("contents", [])):
        tools.append({"code_execution": {}})
    if model.endswith("-search"):
        tools.append({"googleSearch": {}})

    if payload and isinstance(payload, dict) and "tools" in payload:
        items = payload.get("tools", [])
        if items and isinstance(items, list):
            tools.extend(items)

    return tools


def _get_safety_settings(model: str) -> List[Dict[str, str]]:
    """获取安全设置"""
    if model == "gemini-2.0-flash-exp":
        return [
            {"category": "HARM_CATEGORY_HARASSMENT", "threshold": "OFF"},
            {"category": "HARM_CATEGORY_HATE_SPEECH", "threshold": "OFF"},
            {"category": "HARM_CATEGORY_SEXUALLY_EXPLICIT", "threshold": "OFF"},
            {"category": "HARM_CATEGORY_DANGEROUS_CONTENT", "threshold": "OFF"},
            {"category": "HARM_CATEGORY_CIVIC_INTEGRITY", "threshold": "OFF"}
        ]
    return [
        {"category": "HARM_CATEGORY_HARASSMENT", "threshold": "BLOCK_NONE"},
        {"category": "HARM_CATEGORY_HATE_SPEECH", "threshold": "BLOCK_NONE"},
        {"category": "HARM_CATEGORY_SEXUALLY_EXPLICIT", "threshold": "BLOCK_NONE"},
        {"category": "HARM_CATEGORY_DANGEROUS_CONTENT", "threshold": "BLOCK_NONE"},
        {"category": "HARM_CATEGORY_CIVIC_INTEGRITY", "threshold": "BLOCK_NONE"}
    ]


def _build_payload(model: str, request: GeminiRequest) -> Dict[str, Any]:
    """构建请求payload"""
    payload = request.model_dump()
    return {
        "contents": payload.get("contents", []),
        "tools": _build_tools(model, payload),
        "safetySettings": _get_safety_settings(model),
        "generationConfig": payload.get("generationConfig", {}),
        "systemInstruction": payload.get("systemInstruction", [])
    }


class GeminiChatService:
    """聊天服务"""

    def __init__(self, base_url: str, key_manager: KeyManager):
        self.api_client = GeminiApiClient(base_url)
        self.key_manager = key_manager
        self.response_handler = GeminiResponseHandler()
        
    def _extract_text_from_response(self, response: Dict[str, Any]) -> str:
        """从响应中提取文本内容"""
        if not response.get("candidates"):
            return ""
            
        candidate = response["candidates"][0]
        content = candidate.get("content", {})
        parts = content.get("parts", [])
        
        if parts and "text" in parts[0]:
            return parts[0].get("text", "")
        return ""
        
    def _create_char_response(self, original_response: Dict[str, Any], text: str) -> Dict[str, Any]:
        """创建包含指定文本的响应"""
        response_copy = json.loads(json.dumps(original_response))  # 深拷贝
        if response_copy.get("candidates") and response_copy["candidates"][0].get("content", {}).get("parts"):
            response_copy["candidates"][0]["content"]["parts"][0]["text"] = text
        return response_copy

    async def generate_content(self, model: str, request: GeminiRequest, api_key: str) -> Dict[str, Any]:
        """生成内容"""
        payload = _build_payload(model, request)
        response = await self.api_client.generate_content(payload, model, api_key)
        return self.response_handler.handle_response(response, model, stream=False)

    async def stream_generate_content(self, model: str, request: GeminiRequest, api_key: str) -> AsyncGenerator[str, None]:
        """流式生成内容"""
        retries = 0
        max_retries = 3
        payload = _build_payload(model, request)
        while retries < max_retries:
            try:
                async for line in self.api_client.stream_generate_content(payload, model, api_key):
                    # print(line)
                    if line.startswith("data:"):
                        line = line[6:]
                        response_data = self.response_handler.handle_response(json.loads(line), model, stream=True)
                        text = self._extract_text_from_response(response_data)
                        
                        # 如果有文本内容，使用流式输出优化器处理
                        if text:
                            # 使用流式输出优化器处理文本输出
                            async for optimized_chunk in gemini_optimizer.optimize_stream_output(
                                text,
                                lambda t: self._create_char_response(response_data, t),
                                lambda c: "data: " + json.dumps(c) + "\n\n"
                            ):
                                yield optimized_chunk
                        else:
                            # 如果没有文本内容（如工具调用等），整块输出
                            yield "data: " + json.dumps(response_data) + "\n\n"
                logger.info("Streaming completed successfully")
                break
            except Exception as e:
                retries += 1
                logger.warning(f"Streaming API call failed with error: {str(e)}. Attempt {retries} of {max_retries}")
                api_key = await self.key_manager.handle_api_failure(api_key)
                logger.info(f"Switched to new API key: {api_key}")
                if retries >= max_retries:
                    logger.error(f"Max retries ({max_retries}) reached for streaming. Raising error")
                    break