File size: 3,289 Bytes
9a43741 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 | # server.py
import os
import json
from typing import List, Optional, AsyncGenerator
from fastapi import FastAPI, HTTPException, Header
from fastapi.responses import StreamingResponse
from pydantic import BaseModel
import httpx
SERVER_API_KEY = os.getenv("OPENROUTER_API_KEY") # optional fallback
OPENROUTER_BASE_URL = "https://openrouter.ai/api/v1/chat/completions"
DEFAULT_MODEL = "openai/gpt-4o-mini" # change as desired
app = FastAPI(title="OpenRouter Chat Backend")
class Message(BaseModel):
role: str # "system" | "user" | "assistant"
content: str
class ChatRequest(BaseModel):
messages: List[Message]
model: Optional[str] = None
temperature: Optional[float] = 0.7
max_tokens: Optional[int] = None
@app.post("/chat")
async def chat(
req: ChatRequest,
x_openrouter_api_key: Optional[str] = Header(default=None, alias="X-OpenRouter-Api-Key"),
http_referer: Optional[str] = Header(default=None, alias="HTTP-Referer"),
):
model = req.model or DEFAULT_MODEL
# Prefer per-request key from client; fallback to server key if available
api_key = x_openrouter_api_key or SERVER_API_KEY
if not api_key:
raise HTTPException(status_code=401, detail="Missing OpenRouter API key")
headers = {
"Authorization": f"Bearer {api_key}",
"Content-Type": "application/json",
# Attribution headers (optional)
"HTTP-Referer": http_referer or "http://localhost:8501",
"X-Title": "OpenRouter Streamlit Chat",
}
payload = {
"model": model,
"messages": [m.dict() for m in req.messages],
"temperature": req.temperature,
"max_tokens": req.max_tokens,
"stream": True,
}
async def stream() -> AsyncGenerator[bytes, None]:
try:
async with httpx.AsyncClient(timeout=None) as client:
async with client.stream("POST", OPENROUTER_BASE_URL, headers=headers, json=payload) as r:
if r.status_code >= 400:
text = await r.aread()
raise HTTPException(status_code=r.status_code, detail=text.decode("utf-8"))
async for line in r.aiter_lines():
if not line:
continue
if line.startswith("data: "):
data = line[len("data: "):]
if data.strip() == "[DONE]":
yield b"event: done\ndata: done\n\n"
break
try:
obj = json.loads(data)
delta = obj.get("choices", [{}])[0].get("delta", {})
content = delta.get("content")
if content:
yield f"data: {json.dumps({'content': content})}\n\n".encode("utf-8")
except Exception:
yield f"data: {json.dumps({'raw': data})}\n\n".encode("utf-8")
except HTTPException:
raise
except Exception as e:
raise HTTPException(status_code=500, detail=str(e))
return StreamingResponse(stream(), media_type="text/event-stream") |