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| import asyncio
import json
import uuid
from typing import Optional
import httpx
import redis.asyncio as aioredis
from fastapi import FastAPI, WebSocket, WebSocketDisconnect
app = FastAPI()
DEEPSEEK_API_KEY = "your-api-key"
MODEL = "deepseek-chat"
MAX_CONNECTIONS = 50
RATE_LIMIT = 10
class ConnectionManager:
def __init__(self):
self.connections: dict[str, WebSocket] = {}
self.rate_limits: dict[str, list[float]] = {}
async def connect(self, client_id: str, websocket: WebSocket):
if len(self.connections) >= MAX_CONNECTIONS:
await websocket.close(code=1008, reason="服务器繁忙")
return False
await websocket.accept()
self.connections[client_id] = websocket
return True
def disconnect(self, client_id: str):
self.connections.pop(client_id, None)
self.rate_limits.pop(client_id, None)
def check_rate_limit(self, client_id: str) -> bool:
import time
now = time.time()
timestamps = self.rate_limits.get(client_id, [])
timestamps = [t for t in timestamps if now - t < 1]
if len(timestamps) >= RATE_LIMIT:
return False
timestamps.append(now)
self.rate_limits[client_id] = timestamps
return True
manager = ConnectionManager()
class SessionStore:
def __init__(self):
self.redis = None
async def init(self):
self.redis = await aioredis.from_url("redis://localhost:6379")
async def get_messages(self, session_id: str) -> list[dict]:
data = await self.redis.get(f"session:{session_id}")
return json.loads(data) if data else []
async def add_message(self, session_id: str, message: dict):
messages = await self.get_messages(session_id)
messages.append(message)
messages = messages[-50:]
await self.redis.setex(f"session:{session_id}", 7200, json.dumps(messages))
store = SessionStore()
async def stream_llm(websocket: WebSocket, messages: list[dict]):
"""流式调用 LLM 并逐 chunk 发送给客户端"""
full_content = ""
async with httpx.AsyncClient(timeout=120) as client:
async with client.stream(
"POST",
"https://api.deepseek.com/v1/chat/completions",
headers={"Authorization": f"Bearer {DEEPSEEK_API_KEY}"},
json={"model": MODEL, "messages": messages, "stream": True}
) as response:
async for line in response.aiter_lines():
if not line.startswith("data: "):
continue
data_str = line[6:].strip()
if data_str == "[DONE]":
await websocket.send_json({
"type": "ai_stream_end",
"session_id": messages[0].get("session_id", "")
})
return full_content
try:
chunk = json.loads(data_str)
delta = chunk["choices"][0]["delta"]
content = delta.get("content", "")
if content:
full_content += content
await websocket.send_json({
"type": "ai_stream_chunk",
"content": content
})
except json.JSONDecodeError:
continue
return full_content
@app.websocket("/ai-chat/{session_id}")
async def ai_chat(websocket: WebSocket, session_id: str):
client_id = str(uuid.uuid4())[:8]
if not await manager.connect(client_id, websocket):
return
history = await store.get_messages(session_id)
if history:
await websocket.send_json({
"type": "history",
"messages": history
})
system_prompt = {
"role": "system",
"content": "你是一个友好的 AI 助手。请用中文回复，保持对话自然流畅。"
}
messages = [system_prompt] + history
try:
while True:
data = await websocket.receive_json()
if not manager.check_rate_limit(client_id):
await websocket.send_json({
"type": "error",
"content": "消息发送太频繁，请稍后再试"
})
continue
if data["type"] == "user_message":
user_msg = {"role": "user", "content": data["content"]}
messages.append(user_msg)
await store.add_message(session_id, user_msg)
await websocket.send_json({"type": "typing"})
full_reply = await stream_llm(websocket, messages)
ai_msg = {"role": "assistant", "content": full_reply}
messages.append(ai_msg)
await store.add_message(session_id, ai_msg)
elif data["type"] == "ping":
await websocket.send_json({"type": "pong"})
except WebSocketDisconnect:
manager.disconnect(client_id)
print(f"客户端 {client_id} 断开，会话 {session_id} 已保存")
@app.on_event("startup")
async def startup():
await store.init()
if __name__ == "__main__":
import uvicorn
uvicorn.run(app, host="0.0.0.0", port=8000)
|
