app.py

from fastapi import FastAPI, HTTPException, Request
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel
from enum import Enum
import os
from sentence_transformers import SentenceTransformer

model = SentenceTransformer(
        "dunzhang/stella_en_400M_v5",
        trust_remote_code=True,
        device="cpu",
        config_kwargs={"use_memory_efficient_attention": False, "unpad_inputs": False}
    )

class Enum(str, Enum):
    s2p_query = "s2p_query" # sentence-to-sentence
    s2s_query = "s2s_query" # sentence-to-passage, Q&A

class Embedding(BaseModel):
    input: list[str]
    embedding_type: Enum = None
    
    
app = FastAPI()

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["POST"],
    allow_headers=["Authorization"]
)

def parse(data):
    result = []
    for dimension in data:
        temp = []
        for val in dimension:
            temp.append(round(val, 8))
        result.append(temp)
    return result


@app.post("/embeddings/")
async def get_embedding(embedding: Embedding, req: Request):
    
    token = req.headers.get("Authorization")
    if os.environ.get('token') != token[7:]:
        raise HTTPException(status_code=401, detail="Unauthorized.")
    
    if model == None:
        raise HTTPException(status_code=400, detail="Model load failed.")
    
    if embedding.embedding_type == None:
        data = model.encode(embedding.input).tolist()
        return parse(data)
    else:
        data = model.encode(embedding.input, prompt_name=embedding.embedding_type).tolist()
        return parse(data)