Python - Function Decorators: Wrapping Functions(Creating a Function Decorator, nested function, Handling Arguments)

Head First Python

開発環境

• macOS Sierra - Apple (OS)
• Emacs (Text Editor)
• Python 3.6 (プログラミング言語)

Head First Python (Paul Barry (著)、O'Reilly Media)のChapter 10.(Function Decorators: Wrapping Functions) の SHARPEN YOUR PENCIL(No. 7593) を取り組んでみる。

SHARPEN YOUR PENCIL(No. 7593)

コード(Emacs)

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

from flask import Flask, session

app = Flask(__name__)

app.secret_key = 'YouWillNeverGuess'


@app.route('/login')
def do_login() -> str:
    session['logged_in'] = True
    return 'You are now logged in'


@app.route('/logout')
def do_logout() -> str:
    if 'logged_in' in session:
        del session['logged_in']
    return 'You are now logged out'


@app.route('/status')
def check_status() -> str:
    if 'logged_in' in session:
        return 'You are currently logged in'
    return 'You are NOT logged in'


def check_logged_in(func):
    def wrapper(*args, **kwargs):
        if 'logged_in' in session:
            return func(*args, **kwargs)
        return 'You are NOT logged in'
    return wrapper

if __name__ == '__main__':
    app.run(debug=True)

入出力結果(Terminal, IPython)

$ ./sample5.py
 * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 873-014-066
127.0.0.1 - - [12/Apr/2017 16:48:37] "GET /status HTTP/1.1" 200 -
127.0.0.1 - - [12/Apr/2017 16:48:37] "GET /favicon.ico HTTP/1.1" 404 -
127.0.0.1 - - [12/Apr/2017 16:48:43] "GET /login HTTP/1.1" 200 -
127.0.0.1 - - [12/Apr/2017 16:48:43] "GET /login HTTP/1.1" 200 -
127.0.0.1 - - [12/Apr/2017 16:48:47] "GET /status HTTP/1.1" 200 -
127.0.0.1 - - [12/Apr/2017 16:48:48] "GET /status HTTP/1.1" 200 -
127.0.0.1 - - [12/Apr/2017 16:48:51] "GET /login HTTP/1.1" 200 -
127.0.0.1 - - [12/Apr/2017 16:48:51] "GET /logout HTTP/1.1" 200 -
127.0.0.1 - - [12/Apr/2017 16:48:52] "GET /logout HTTP/1.1" 200 -
127.0.0.1 - - [12/Apr/2017 16:48:55] "GET /status HTTP/1.1" 200 -
127.0.0.1 - - [12/Apr/2017 16:48:55] "GET /status HTTP/1.1" 200 -
  C-c C-c$