main.py

#!/usr/bin/env python
# encoding: utf-8

from fastapi import FastAPI, Form, Depends, Request
from fastapi.encoders import jsonable_encoder
from fastapi.responses import JSONResponse
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel
import pickle

app = FastAPI()

# Add CORS middleware
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],  # Replace with the list of allowed origins for production
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

model_file = open('insurance_model.pkl', 'rb')
model = pickle.load(model_file, encoding='bytes')


class Msg(BaseModel):
    msg: str


class Req(BaseModel):
    age: int
    sex: int
    smoker: int
    bmi: float
    children: int
    region: int

class Resp(BaseModel):
    age: int
    sex: str
    smoker: str
    bmi: float
    children: int
    region: str
    insurance_cost: float



@app.get("/")
async def root():
    return {"message": "Hello World. Welcome to FastAPI!"}

def form_req(age: str = Form(...), sex: str = Form(...), smoker: str = Form(...),
             bmi: str = Form(...), children: str = Form(...), region: str = Form(...)):
    sBmi = bmi.replace(",", ".")
    return Req(age=int(age), sex=int(sex), smoker=int(smoker), bmi=float(sBmi), children=int(children), region=int(region))


@app.get("/path")
async def demo_get():
    return {"message": "This is /path endpoint, use a post request to transform the text to uppercase"}


@app.post("/path")
async def demo_post(inp: Msg):
    return {"message": inp.msg.upper()}


@app.get("/path/{path_id}")
async def demo_get_path_id(path_id: int):
    return {"message": f"This is /path/{path_id} endpoint, use post request to retrieve result"}


@app.get("/predict/{path_id}")
async def predict(path_id: int):
    return {"message":  f"This is /predict/{path_id} endpoint, use post request to retrieve result"}

def get_region_name(region_code):
    region_mapping = {
        0: "Northeast",
        1: "Northwest",
        2: "Southeast",
        3: "Southwest"
    }
    return region_mapping.get(region_code, "Unknown")

@app.post("/predict")
async def predict(request: Request, requess: Req = Depends(form_req)):
    '''
    Predict the insurance cost based on user inputs
    and render the result to the html page
    '''
    age = requess.age
    sex = requess.sex
    smoker = requess.smoker
    bmi = requess.bmi
    children = requess.children
    region = requess.region
    data = []

    data.append(int(age))
    data.extend([int(sex)])
    data.extend([float(bmi)])
    data.extend([int(children)])
    data.extend([int(smoker)])
    data.extend([int(region)])

    prediction = model.predict([data])
    output = round(prediction[0], 2)

    sex = "Male" if requess.sex == 1 else "Female"
    smoker = "Yes" if requess.smoker == 1 else "No"

    # Render index.html with prediction results
    json_compatible_resp_data = jsonable_encoder(Resp(age=requess.age, sex=sex, smoker=smoker, 
                                                      bmi=requess.bmi, children=requess.children, region=get_region_name(requess.region), insurance_cost=output))
    return JSONResponse(content=json_compatible_resp_data)