changing fast api of python to express server

[yeab14]

from fastapi import FastAPI, HTTPException, UploadFile, File from fastapi.middleware.cors import CORSMiddleware from pydantic import BaseModel from transformers import AutoModelForCausalLM, AutoTokenizer, pipeline from typing import List, Optional import shutil import os import uuid

app = FastAPI()

CORS configuration

app.add_middleware( CORSMiddleware, allow_origins=[""], # Replace with your frontend URL if known allow_credentials=True, allow_methods=[""], allow_headers=["*"], )

Load Pygmalion 7B model and tokenizer

model_name = "EleutherAI/gpt-neo-2.7B" tokenizer = AutoTokenizer.from_pretrained(model_name) model = AutoModelForCausalLM.from_pretrained(model_name) generator = pipeline("text-generation", model=model, tokenizer=tokenizer)

Pydantic models

class ChatRequest(BaseModel): user_input: str character_id: str

class ChatResponse(BaseModel): response: str

class CharacterBase(BaseModel): name: str greeting: str personality_description: str backstory: str

class CharacterCreate(CharacterBase): pass

class Character(CharacterBase): id: str avatar_url: Optional[str] = None

In-memory storage for characters (replace with database in production)

characters_db = {}

Create character endpoint

@app.post("/characters/", response_model=Character) async def create_character(character: CharacterCreate, avatar: UploadFile = File(...)): char_id = str(uuid.uuid4()) avatar_filename = f"{charid}{avatar.filename}" avatar_path = os.path.join("avatars", avatar_filename)

with open(avatar_path, "wb") as buffer:
    shutil.copyfileobj(avatar.file, buffer)

new_character = Character(
    id=char_id,
    name=character.name,
    greeting=character.greeting,
    personality_description=character.personality_description,
    backstory=character.backstory,
    avatar_url=f"/avatars/{avatar_filename}"
)
characters_db[char_id] = new_character
return new_character

List all characters endpoint

@app.get("/characters/", response_model=List[Character]) async def list_characters(): return list(characters_db.values())

Get character by ID endpoint

@app.get("/characters/{char_id}", response_model=Character) async def get_character(char_id: str): character = characters_db.get(char_id) if not character: raise HTTPException(status_code=404, detail="Character not found") return character

Chat endpoint

@app.post("/chat", response_model=ChatResponse) async def chat(request: ChatRequest): user_input = request.user_input character = characters_db.get(request.character_id) if not character: raise HTTPException(status_code=404, detail="Character not found")

# Customize the conversation based on character's backstory and personality
prompt = f"{character.greeting}\n\n{character.backstory}\n\nUser: {user_input}\n{character.name}:"
try:
    responses = generator(prompt, max_length=100, num_return_sequences=1)
    response_text = responses[0]['generated_text'].split(f"{character.name}:")[1].strip()
    return ChatResponse(response=response_text)
except Exception as e:
    raise HTTPException(status_code=500, detail=str(e))

Entry point

if name == "main": import uvicorn uvicorn.run(app, host="localhost", port=8000) how to change this fast api server of python to express server ?

[yeab14]

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