An example application that manages a simple in-memory database of books using Litestar for Python

app_datamodel.py

from __future__ import annotations
from dataclasses import dataclass
from litestar import Litestar, post, get, patch, put
from litestar.dto import DataclassDTO, DTOConfig, DTOData
from litestar.exceptions import HTTPException

@dataclass
class Book:
    title: str
    author: str
    publisher: str
    genre: str
    book_id: int
      
BOOKS_DB = {}
BOOK_IX = 1

class ReadDTO(DataclassDTO[Book]):
    config = DTOConfig()
class WriteDTO(DataclassDTO[Book]):
    config = DTOConfig(exclude={"book_id"})
class PatchDTO(DataclassDTO[Book]):
    config = DTOConfig(exclude={"book_id"}, partial=True)
    
@get(path="/books", sync_to_thread=False)
def get_books() -> dict:
    return BOOKS_DB

@get(path="/book/{book_id:int}", return_dto=ReadDTO, sync_to_thread=False)
def get_book(book_id: int) -> Book:
    book = BOOKS_DB.get(book_id, False)
    if not(book):
        raise HTTPException(status_code=400, detail=f"book with id [{book_id}] not found")
    return book

@post(path="/book", dto=WriteDTO, return_dto=ReadDTO, sync_to_thread=False)
def create_book(data: DTOData[Book]) -> Book:
    global BOOK_IX
    new_book = data.create_instance(book_id=BOOK_IX)
    BOOK_IX += 1
    book_id = new_book.book_id
    BOOKS_DB[book_id] = new_book
    return new_book
  
@put(path="/book/{book_id:int}", dto=WriteDTO, return_dto=ReadDTO, sync_to_thread=False)
def update_book(book_id: int, data: DTOData[Book]) -> Book:
    book = BOOKS_DB.get(book_id, False)
    if not(book):
        raise HTTPException(status_code=400, detail=f"book with id [{book_id}] not found")
    data.update_instance(book)
    return book
  
@patch(path="/book/{book_id:int}", dto=PatchDTO, return_dto=ReadDTO, sync_to_thread=False)
def partial_update_book(book_id: int, data: DTOData[Book]) -> Book:
    book = BOOKS_DB.get(book_id, False)
    if not(book):
        raise HTTPException(status_code=400, detail=f"book with id [{book_id}] not found")
    data.update_instance(book)
    return book

app = Litestar(route_handlers=[create_book, get_book, get_books, partial_update_book, update_book])