main.py

from fastapi import FastAPI
from pydantic import BaseModel, Field
from pathlib import Path
from datetime import datetime
import json

class Message(BaseModel):
    user: str
    content: str
    ts: datetime = Field(default_factory=datetime.now) # instantiated to now 


base_file = Path("salon.json")

if not base_file.exists():
    with open(base_file, "w") as f:
        f.write("[]") # Create an empty list 
        
app = FastAPI()


@app.get("/messages")
async def get_messages():
    with open(base_file) as f:
        return json.load(f)

@app.post("/publish")
async def post_message(message: Message):
    with open(base_file) as f:
        d = json.load(f)
    d.append(message)
    with open(base_file, "w") as f:
        json.dump(d, f)