Modular Routing

# routers/employees.py
from fastapi import APIRouter, HTTPException, status
from pydantic import BaseModel

# 1. Create the APIRouter instance
router = APIRouter(
    prefix="/employees",
    tags=["Employees"]
)

class Employee(BaseModel):
    id: int
    name: str
    department: str

# Sample Mock Database
EMPLOYEES = [
    Employee(id=1, name="Alice", department="Engineering"),
    Employee(id=2, name="Bob", department="HR")
]

# 2. Add endpoints using @router instead of @app
@router.get("/", response_model=list[Employee])
def list_employees():
    return EMPLOYEES

@router.get("/{emp_id}", response_model=Employee)
def get_employee(emp_id: int):
    for emp in EMPLOYEES:
        if emp.id == emp_id:
            return emp
    raise HTTPException(status_code=404, detail="Employee not found")

# main.py
from fastapi import FastAPI
# Import the employee router we created
from routers import employees

app = FastAPI(title="Employee Management System")

# Register the sub-router
app.include_router(employees.router)

@app.get("/")
def home():
    return {"message": "Welcome to the Modular EMS API!"}

my_project/
│
├── main.py                # App entrypoint
├── routers/               # APIRouter files
│   ├── __init__.py        # Makes routers a package
│   ├── employees.py       # Employee route endpoints
│   └── departments.py     # Department route endpoints