item.py

import sqlite3
from flask_restful import Resource, reqparse
from flask_jwt import jwt_required


class Item(Resource):
    parser = reqparse.RequestParser()
    parser.add_argument('price',
          type = float,
          required = True,
          help = "This field cannot left blank!"
    )

    @classmethod
    def find_by_name(cls, name):
        connection = sqlite3.connect('data.db')
        cursor = connection.cursor()

        query = "SELECT * FROM items WHERE name=?"
        result = cursor.execute(query, (name,))
        row = result.fetchone() 
        connection.close()

        if row:
            return {'item': {'name': row[0], 'price': row[1]}}

    @jwt_required()
    def get(self, name):
        item = self.find_by_name(name)
        if item:
            return item
        return {'message':"Item not found!"}, 404

    def post(self, name):
        if self.find_by_name(name):                         # if Item.find_by_name(name) also works
            return{'message': "An item with name '{}' already exists.".format(name)}, 400

        data = Item.parser.parse_args()

        item = {'name': name, 'price': data['price']}

        try:
            self.insert(item)
        except:
            return{"message": "Ein Error!"}, 500

        return item, 201

    @classmethod
    def insert(cls, item):
        connection = sqlite3.connect('data.db')
        cursor = connection.cursor()

        query = "INSERT INTO items VALUES (?,?)"
        cursor.execute(query, (item['name'], item['price']))

        connection.commit()
        connection.close()


    @jwt_required()
    def delete(self, name):
        item = self.find_by_name(name)

        if item:
            connection = sqlite3.connect('data.db')
            cursor = connection.cursor()

            query = "DELETE FROM items WHERE name=?"
            cursor.execute(query, (name,))

            connection.commit()
            connection.close()

            return{'message': '{}'"got deleted from db.".format(name)}, 200
        else:
            return {'message': "Item '{}' does not exist.".format(name)}, 404
    
    @jwt_required()
    def put(self, name):
        data = Item.parser.parse_args()
        item = self.find_by_name(name)
        updated_item = {'name': name, 'price': data['price']}

        if item is None:
            try:
                Item.insert(updated_item)
            except:
                return {"message": "Big Error1!"}, 500
        else:
            try:
                Item.update(updated_item)
            except:
                raise
                return {"message": "Fetter Error2!"}, 500
        return updated_item

    @classmethod
    def update(cls, item):
        connection = sqlite3.connect('data.db')
        cursor = connection.cursor()

        query = "UPDATE items SET price=? WHERE name=?"
        cursor.execute(query, (item['price'],item['name']))

        connection.commit()
        connection.close()

class ItemList(Resource):

    def get(self):
        connection = sqlite3.connect('data.db')
        cursor = connection.cursor()

        query = "SELECT * FROM items"
        result = cursor.execute(query)
        items = []

        for row in result:
            items.append({'name': row[0], 'price': row[1]})

        connection.close()

        return {'items': items}