Code for How to Build a CRUD App with Flask and SQLAlchemy in Python Tutorial

config.py

import os


class Config:
    SQLALCHEMY_TRACK_MODIFICATIONS = False

    @staticmethod
    def init_app(app):
        pass


class DevelopmentConfig(Config):
    DEBUG = True
    SQLALCHEMY_DATABASE_URI = os.getenv("DEV_DATABASE_URL")


class TestingConfig(Config):
    TESTING = True
    SQLALCHEMY_DATABASE_URI = os.getenv("TEST_DATABASE_URL")


class ProductionConfig(Config):
    SQLALCHEMY_DATABASE_URI = os.getenv("DATABASE_URL")


config = {
    'development': DevelopmentConfig,
    'testing': TestingConfig,
    'production': ProductionConfig,
    'default': DevelopmentConfig
}

bookshop.py

from app import db
from app.routes import app
from app.models import Book


@app.shell_context_processor
def make_shell_context():
    return dict(db=db, Book=Book)

app/__init__.py

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from config import config

db = SQLAlchemy()


def create_app(config_name):
    app = Flask(__name__)
    app.config.from_object(config[config_name])
    config[config_name].init_app(app)

    db.init_app(app)
    return app

app/models.py

from . import db


class Book(db.Model):
    __tablename__ = 'books'
    isbn = db.Column(db.Integer, primary_key=True)
    author = db.Column(db.String(100), nullable=False)
    title = db.Column(db.String(100), nullable=False)
    price = db.Column(db.Float)

    def to_json(self):
        return {
            'isbn': self.isbn,
            'author': self.author,
            'title': self.title,
            'price': self.price
        }

app/routes.py

import os
from . import create_app
from .models import Book
from . import db
from flask import jsonify, request, abort

app = create_app(os.getenv('FLASK_CONFIG') or 'default')


@app.route("/book/list", methods=["GET"])
def get_books():
    books = Book.query.all()
    return jsonify([book.to_json() for book in books])


@app.route("/book/<int:isbn>", methods=["GET"])
def get_book(isbn):
    book = Book.query.get(isbn)
    if book is None:
        abort(404)
    return jsonify(book.to_json())


@app.route("/book/<int:isbn>", methods=["DELETE"])
def delete_book(isbn):
    book = Book.query.get(isbn)
    if book is None:
        abort(404)
    db.session.delete(book)
    db.session.commit()
    return jsonify({'result': True})


@app.route('/book', methods=['POST'])
def create_book():
    if not request.json:
        abort(400)
    book = Book(
        title=request.json.get('title'),
        author=request.json.get('author'),
        price=request.json.get('price')
    )
    db.session.add(book)
    db.session.commit()
    return jsonify(book.to_json()), 201


@app.route('/book/<int:isbn>', methods=['PUT'])
def update_book(isbn):
    if not request.json:
        abort(400)
    book = Book.query.get(isbn)
    if book is None:
        abort(404)
    book.title = request.json.get('title', book.title)
    book.author = request.json.get('author', book.author)
    book.price = request.json.get('price', book.price)
    db.session.commit()
    return jsonify(book.to_json())