myapi.py

from fastapi import FastAPI, HTTPException, Depends
from sqlalchemy import create_engine, Column, Integer, String
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker, Session

from pydantic import BaseModel
from typing import List, Optional

app = FastAPI(title = "Integration")

#database setup
engine = create_engine("sqlite:///users.db", connect_args = {"check_same_thread": False})
SessionLocal = sessionmaker(autocommit = False, autoflush=False, bind = engine)
Base = declarative_base()

#db model
class User(Base):
    __tablename__ = "users"
    id = Column(Integer, primary_key=True, index=True)
    name = Column(String(100), nullable=False)
    email = Column(String(100), unique=True, nullable=False)
    role = Column(String(100), nullable=False)

Base.metadata.create_all(bind=engine) #model speaks to enginer 

#pydantic models
class UserCreate(BaseModel):
    name: str
    email: str
    role: str

class UserResponse(BaseModel):
    id: int
    name: str
    email: str
    role: str

    class Config:
        from_attributes = True

def get_db():
    try:
        yield SessionLocal()
    finally:
        SessionLocal().close()

get_db()

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

@app.get("/users/{user_id}", response_model=UserResponse)
def get_user(user_id: int, db: Session = Depends(get_db)):
    user = db.query(User).filter(User.id == user_id).first()
    if not user:
        raise HTTPException(status_code=404, detail="User not found")
    return user

@app.post("/users/", response_model=UserResponse)
def create_user(user: UserCreate, db: Session = Depends(get_db)):
    if db.query(User).filter(User.email == user.email).first():
        raise HTTPException(status_code=400, detail="Email already registered")
    new_user = User(**user.dict())
    db.add(new_user)
    db.commit()
    db.refresh(new_user)
    return new_user
#update user 
@app.put("/users/{user_id}", response_model=UserResponse)
def update_user(user_id:int, user: UserCreate, db:Session = Depends(get_db)):
    existing_user = db.query(User).filter(User.id == user_id).first()
    if not existing_user:
        raise HTTPException(status_code=404, detail="User not found")
    if db.query(User).filter(User.email == user.email, User.id != user_id).first():
        raise HTTPException(status_code=400, detail="Email already registered")

    for feild, value in user.dict().items():
        setattr(existing_user, feild, value)

    db.commit()
    db.refresh(existing_user)
    return existing_user

#delete
@app.delete("/users/{user_id}")
def delete_user(user_id: int, db: Session = Depends(get_db)):
    user = db.query(User).filter(User.id == user_id).first()
    if not user:
        raise HTTPException(status_code=404, detail="User not found")
    db.delete(user)
    db.commit()
    return {"detail": "User deleted successfully"}

#get all user 
@app.get("/users/", response_model=List[UserResponse])
def get_all_users(db: Session = Depends(get_db)):
    users = db.query(User).all()
    return users