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| from fastapi import FastAPI, HTTPException, Request | |
| from fastapi.responses import JSONResponse, StreamingResponse | |
| from fastapi.middleware.cors import CORSMiddleware | |
| import requests | |
| import json | |
| import os | |
| import time | |
| import asyncio | |
| app = FastAPI() | |
| # CORS 设置 | |
| app.add_middleware( | |
| CORSMiddleware, | |
| allow_origins=["*"], # 允许所有来源，生产环境请修改为具体的域名 | |
| allow_credentials=True, | |
| allow_methods=["*"], | |
| allow_headers=["*"], | |
| ) | |
| # 环境变量配置 | |
| STATUS_URL = os.environ.get("STATUS_URL", "https://duckduckgo.com/duckchat/v1/status") | |
| CHAT_URL = os.environ.get("CHAT_URL", "https://duckduckgo.com/duckchat/v1/chat") | |
| REFERER = os.environ.get("REFERER", "https://duckduckgo.com/") | |
| ORIGIN = os.environ.get("ORIGIN", "https://duckduckgo.com") | |
| USER_AGENT = os.environ.get("USER_AGENT", "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36") | |
| COOKIE = os.environ.get("COOKIE", "dcm=3; s=l; bf=1") # 从环境变量获取 Cookie | |
| DEFAULT_HEADERS = { | |
| "User-Agent": USER_AGENT, | |
| "Accept": "text/event-stream", | |
| "Accept-Language": "en-US,en;q=0.5", | |
| "Referer": REFERER, | |
| "Content-Type": "application/json", | |
| "Origin": ORIGIN, | |
| "Connection": "keep-alive", | |
| "Cookie": COOKIE, | |
| "Sec-Fetch-Dest": "empty", | |
| "Sec-Fetch-Mode": "cors", | |
| "Sec-Fetch-Site": "same-origin", | |
| "Pragma": "no-cache", | |
| "TE": "trailers", | |
| } | |
| SUPPORTED_MODELS = ["o3-mini", "gpt-4o-mini", "claude-3-haiku-20240307", "meta-llama/Llama-3.3-70B-Instruct-Turbo"] | |
| async def get_vqd(): | |
| """获取 DuckDuckGo Chat 的 VQD 值。""" | |
| headers = {**DEFAULT_HEADERS, "x-vqd-accept": "1"} | |
| try: | |
| response = requests.get(STATUS_URL, headers=headers) | |
| response.raise_for_status() # 抛出 HTTPError，如果状态码不是 200 | |
| vqd = response.headers.get("x-vqd-4") | |
| if not vqd: | |
| raise ValueError("x-vqd-4 header 在响应中未找到。") | |
| return vqd | |
| except requests.exceptions.RequestException as e: | |
| raise HTTPException(status_code=500, detail=f"HTTP 请求失败: {e}") | |
| except ValueError as e: | |
| raise HTTPException(status_code=500, detail=str(e)) | |
| async def duckduckgo_chat_stream(model, messages): | |
| """与 DuckDuckGo Chat 进行交互，流式输出。""" | |
| try: | |
| x_vqd_4 = await get_vqd() | |
| chat_headers = { | |
| **DEFAULT_HEADERS, | |
| "x-vqd-4": x_vqd_4, | |
| "Accept": "text/event-stream", # 确保接受 SSE | |
| } | |
| body = json.dumps({ | |
| "model": model, | |
| "messages": messages, | |
| }) | |
| response = requests.post(CHAT_URL, headers=chat_headers, data=body, stream=True) | |
| response.raise_for_status() | |
| async def event_stream(): | |
| try: | |
| for line in response.iter_lines(): | |
| if line: | |
| decoded_line = line.decode('utf-8') | |
| if decoded_line.startswith("data: "): | |
| try: | |
| json_data = json.loads(decoded_line[5:]) | |
| message_content = json_data.get("message", "") | |
| if message_content: | |
| # 构建 OpenAI 风格的流式响应 | |
| openai_stream_response = { | |
| "id": f"chatcmpl-{int(time.time() * 1000)}", | |
| "object": "chat.completion.chunk", | |
| "created": int(time.time()), | |
| "model": model, | |
| "choices": [ | |
| { | |
| "delta": { | |
| "content": message_content | |
| }, | |
| "index": 0, | |
| "finish_reason": None | |
| } | |
| ], | |
| } | |
| yield f"data: {json.dumps(openai_stream_response)}\n\n" | |
| await asyncio.sleep(0.01) # 避免 CPU 占用过高 | |
| except json.JSONDecodeError as e: | |
| print(f"JSON 解析错误: {e}, 行: {decoded_line}") | |
| yield f"data: {json.dumps({'error': 'JSON 解析错误'})}\n\n" # 返回错误信息 | |
| break # 停止流式传输 | |
| except requests.exceptions.RequestException as e: | |
| print(f"请求错误: {e}") | |
| yield f"data: {json.dumps({'error': '请求错误'})}\n\n" | |
| except Exception as e: | |
| print(f"发生错误: {e}") | |
| yield f"data: {json.dumps({'error': '发生错误'})}\n\n" | |
| finally: | |
| yield "data: [DONE]\n\n" # 结束 SSE 流 | |
| return StreamingResponse(event_stream(), media_type="text/event-stream") | |
| except requests.exceptions.RequestException as e: | |
| raise HTTPException(status_code=500, detail=f"HTTP 请求失败: {e}") | |
| except Exception as e: | |
| raise HTTPException(status_code=500, detail=f"聊天过程中发生错误: {e}") | |
| async def duckduckgo_chat_non_stream(model, messages): | |
| """与 DuckDuckGo Chat 进行交互，非流式输出。""" | |
| try: | |
| x_vqd_4 = await get_vqd() | |
| chat_headers = { | |
| **DEFAULT_HEADERS, | |
| "x-vqd-4": x_vqd_4, | |
| } | |
| body = json.dumps({ | |
| "model": model, | |
| "messages": messages, | |
| }) | |
| response = requests.post(CHAT_URL, headers=chat_headers, data=body) | |
| response.raise_for_status() | |
| full_message = "" | |
| for line in response.iter_lines(): | |
| if line: | |
| decoded_line = line.decode('utf-8') | |
| if decoded_line.startswith("data: "): | |
| try: | |
| json_data = json.loads(decoded_line[5:]) | |
| full_message += json_data.get("message", "") | |
| except json.JSONDecodeError as e: | |
| print(f"JSON 解析错误: {e}, 行: {decoded_line}") | |
| pass # 忽略解析错误 | |
| return full_message | |
| except requests.exceptions.RequestException as e: | |
| raise HTTPException(status_code=500, detail=f"HTTP 请求失败: {e}") | |
| except Exception as e: | |
| raise HTTPException(status_code=500, detail=f"聊天过程中发生错误: {e}") | |
| async def chat_completions(request: Request): | |
| try: | |
| body = await request.json() | |
| if not body: | |
| raise HTTPException(status_code=400, detail="无效的请求体") | |
| model = body.get("model", "o3-mini") | |
| if model not in SUPPORTED_MODELS: | |
| raise HTTPException(status_code=400, detail=f"模型 \"{model}\" 不支持。支持的模型有: {', '.join(SUPPORTED_MODELS)}.") | |
| messages = body.get("messages") | |
| if not messages: | |
| raise HTTPException(status_code=400, detail="未提供任何消息内容") | |
| stream = body.get("stream", False) # 获取 stream 参数，默认为 False | |
| # 处理 system 消息 | |
| system_message = next((msg for msg in messages if msg.get("role") == "system"), None) | |
| system_prompt = f"你将扮演一个{system_message['content']}.\n" if system_message else "" | |
| # 提取历史消息并格式化 | |
| history_messages = "\n".join( | |
| f"{msg['role']}: {msg['content']}" | |
| for msg in messages | |
| if msg.get("role") != "system" and msg != messages[-1] | |
| ) | |
| # 提取最后一条用户消息 | |
| last_user_message = messages[-1] | |
| current_question = last_user_message["content"] if last_user_message.get("role") == "user" else "" | |
| # 构建合并后的消息 | |
| combined_message_content = f"{system_prompt}以下是历史对话记录：\n{history_messages}\n用户当前提问：{current_question}" | |
| combined_message = {"role": "user", "content": combined_message_content} | |
| if stream: | |
| return await duckduckgo_chat_stream(model, [combined_message]) | |
| else: | |
| response_text = await duckduckgo_chat_non_stream(model, [combined_message]) | |
| # 构建 OpenAI 风格的响应 | |
| openai_response = { | |
| "id": f"chatcmpl-{int(time.time() * 1000)}", # 生成唯一 ID | |
| "object": "chat.completion", | |
| "created": int(time.time()), | |
| "model": model, | |
| "choices": [ | |
| { | |
| "message": { | |
| "role": "assistant", | |
| "content": response_text, | |
| }, | |
| "finish_reason": "stop", | |
| "index": 0, | |
| }, | |
| ], | |
| "usage": { | |
| "prompt_tokens": 0, | |
| "completion_tokens": 0, | |
| "total_tokens": 0 | |
| }, | |
| } | |
| return JSONResponse(content=openai_response) | |
| except HTTPException as e: | |
| raise e # 重新抛出 HTTPException，以便 FastAPI 处理 | |
| except Exception as e: | |
| print(f"API 错误: {e}") | |
| raise HTTPException(status_code=500, detail=f"服务器内部错误: {e}") | |
| async def http_exception_handler(request: Request, exc: HTTPException): | |
| return JSONResponse( | |
| status_code=exc.status_code, | |
| content={"detail": exc.detail}, | |
| ) | |
| async def greet_json(): | |
| return {"Hello": "World!"} | |