efsane58911 / flask-database

Simple Flask database integration

Flask Database

Simple Flask database integration

This is a library to make it simple to run sql queries using flask.

When running database queries in Python with Flask, you either need to create a new connection for each request (quite slow) or manage some pool of connections (complicated). DBUtils already solves this problem. This package hooks DBUtils into flask's session so that you can access the database in a simple manner.

Usage

import pymysql  # Can be any database type
import sys
from flask_database import Database
from flask import Flask, request

app = Flask(__name__)
db = Database(
    app,
    pymysql,
    host='127.0.0.1',
    port=3306,
    user='my_user',
    password='123',
    database='my_database'
)

@app.route('/revenue', methods=['GET'])
def get_revenue():
    purchases = db.fetch_all('SELECT price, quantity FROM Purchases')
    revenue = sum(price * quantity for price, quantity in purchases)
    return 'Revenue: ' + str(revenue)

@app.route('/purchase', methods=['POST'])
def post_purchase():
    price = float(request.form['price'])
    quantity = int(request.form['quantity'])
    db.run('INSERT INTO Purchases(price, quantity) VALUES (%s, %s)', (price, quantity))
    return 'Success'


def init_tables():
    db.detach()  # Allows use of database outside Flask request
    db.run('CREATE TABLE Purchases(price DOUBLE NOT NULL, quantity INTEGER NOT NULL)')


if sys.argv[1] == 'init':
    init_tables()
else:
    app.run()

Now, we can interact with our service as you would expect:

curl http://127.0.0.1:5000/revenue
# Revenue: 0

curl -X POST -F 'price=1.25' -F 'quantity=9' http://127.0.0.1:5000/purchase
# Success

curl http://127.0.0.1:5000/revenue
# Revenue: 11.25

Note: to replicate this example you'll have MySQL runnning with the provided database and user set up. Example commands:

sudo apt-get install mysql-server
sudo mysql -u root # If you already set a password use 'mysql -u root -p'

CREATE DATABASE my_database;
CREATE USER my_user@localhost IDENTIFIED BY '123';
GRANT ALL PRIVILEGES ON my_database. * TO my_user@localhost;

python3 example.py init  # Setup tables
python3 example.py  # Run server

Installation

Install via PyPI:

pip3 install --user flask-database