Flask advanced building RESTful API and database interoperation

introductory

In the beginner's tutorial, we have covered how to build basic web applications using Flask. In this intermediate tutorial, we will learn how to build RESTful APIs with Flask and how to use Flask-SQLAlchemy for database operations.

I. Building a RESTful API

REST (Representational State Transfer) is an approach to building Web services that utilizes the four basic operations of the HTTP protocol: GET, POST, PUT, and DELETE. in Flask, we can easily define routes for each HTTP method:

from flask import Flask, request, jsonify
app = Flask(__name__)
todos = []
@('/todos', methods=['GET'])
def get_todos():
    return jsonify(todos)
@('/todos', methods=['POST'])
def add_todo():
    (('todo', ''))
    return '', 204
@('/todos/<int:index>', methods=['PUT'])
def update_todo(index):
    todos[index] = ('todo', '')
    return '', 204
@('/todos/<int:index>', methods=['DELETE'])
def delete_todo(index):
    del todos[index]
    return '', 204

Second, using Flask-SQLAlchemy for database operations

Flask-SQLAlchemy is an extension to Flask that provides all the functionality of SQLAlchemy and adds some handy features to it, such as paging support.

First, you need to install Flask-SQLAlchemy:

pip install flask-sqlalchemy

We can then define a model and perform database operations:

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
app = Flask(__name__)
['SQLALCHEMY_DATABASE_URI'] = 'sqlite:////tmp/'
db = SQLAlchemy(app)
class User():
    id = (, primary_key=True)
    name = ((50))
@('/')
def index():
    user = .filter_by(name='John').first()
    return 'Hello, {}!'.format()

In the above code, we first configured the URI of the database, then defined a User model, and finally performed a database query in the view function.

Above, we introduced how to use Flask to build RESTful APIs and how to use Flask-SQLAlchemy for database operations. Hope this article can help you understand Flask deeply and develop more complex web applications.

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