import osfrom jinja2 import escapefrom flask import Flask, make_response,request, redirect,url_for,abort,session,jsonifyfrom urllib.parse import urlparse, urljoinfrom jinja2.utils import generate_lorem_ipsumapp = Flask(__name__)app.secret_key = os.getenv(‘SECRET_KEY‘, ‘ secret string‘)# 从查询字段和cookies 获取名字@app.route(‘/‘)@app.route(‘/hello‘)def hello(): ???name = request.args.get(‘name‘) ???if name is None: ???????name = request.cookies.get(‘name‘, ‘Human‘) ???response = ‘<h1>Hello %s!</h1>‘ % escape(name) ???# return different response according to the user‘s authentication status ???if ‘logged_in‘ in session: ???????response += ‘[Authenticated]‘ ???else: ???????response += ‘[Not Authenticated]‘ ???return response# 重定向例子@app.route(‘/hi‘)def hi(): ???return redirect(url_for(‘hello‘)) ???# url_for表示程序内路径，去找hello函数@app.route(‘/goback/<int:year>‘)def go_back(year): ???return "<h1>welcome to %d"%(2018-year)@app.route(‘/colors/<any(blue, white, red):color>‘)def three_color(color): ???return "<p>Love is patient and kind. Love is not jealous or boastful or pround or rude.</p>"@app.route(‘/brew/<drink>‘)def reapot(drink): ???if drink == ‘coffee‘: ???????abort(418) ???else: ???????return ‘a drink of tea‘@app.route(‘/404‘)def not_found(): ???abort(404)# 返回不同的数据类型(MIME类型)@app.route(‘/note‘, defaults={‘content_type‘: ‘text‘})@app.route(‘/note/<content_type>‘)def note(content_type): ???content_type = content_type.lower() ???if content_type == ‘text‘: ???????body = ‘‘‘Noteto: Peterfrom: Janeheading: Reminderbody: Don‘t forget the party!‘‘‘ ???????response = make_response(body) ???????response.mimetype = ‘text/plain‘ ???elif content_type == ‘html‘: ???????body = ‘‘‘<!DOCTYPE html><html><head></head><body> ?<h1>Note</h1> ?<p>to: Peter</p> ?<p>from: Jane</p> ?<p>heading: Reminder</p> ?<p>body: <strong>Don‘t forget the party!</strong></p></body></html>‘‘‘ ???????response = make_response(body) ???????response.mimetype = ‘text/html‘ ???elif content_type == ‘xml‘: ???????body = ‘‘‘<?xml version="1.0" encoding="UTF-8"?><note> ?<to>Peter</to> ?<from>Jane</from> ?<heading>Reminder</heading> ?<body>Don‘t forget the party!</body></note>‘‘‘ ???????response = make_response(body) ???????response.mimetype = ‘application/xml‘ ???elif content_type == ‘json‘: ???????body = {"note": { ???????????"to": "Peter", ???????????"from": "Jane", ???????????"heading": "Remider", ???????????"body": "Don‘t forget the party!" ???????} ???????} ???????response = jsonify(body) ???????# equal to: ???????# response = make_response(json.dumps(body)) ???????# response.mimetype = "application/json" ???else: ???????abort(400) ???return response# 设置cookie@app.route(‘/set/<name>‘)def set_cookies(name): ???response = make_response(redirect(url_for(‘hello‘))) ???response.set_cookie(‘name‘, name) ???return response# 实现用户登录 2-5@app.route(‘/login‘)def login(): ???session[‘logged_in‘] = True ???return redirect(url_for(‘hello‘))# 保护视图@app.route(‘/admin‘)def admin(): ???if ‘logged_in‘ ?not in ?session: ???????abort(403) ???return ‘welcome to admin page‘@app.route(‘/logout‘)def logout(): ???if ‘logged_in‘ in session: ???????session.pop(‘logged_in‘) ???return redirect(url_for(‘hello‘))# 返回上一个页面@app.route(‘/foo‘)def foo(): ???return ‘<h1>Foo page</h1><a href="%s"> Do something and redirect</a>‘ ???????????% url_for(‘do_something‘, next=request.full_path)@app.route(‘/bar‘)def bar(): ???return ‘<h1>Bar page</h1> <a href="%s"> Do something and redicrect</a>‘ ???????????% url_for(‘do_something‘, next=request.full_path)@app.route(‘/do-something‘)def do_something(): ???# do something ???return redirect_back()def is_safe_url(target): ???ref_url = urlparse(request.host_url) ?# 获取主机url ???test_url = urlparse(urljoin(request.host_url, target)) ???return test_url.scheme in (‘http‘, ‘https‘) and ????????????ref_url.netloc == test_url.netlocdef redirect_back(default=‘hello‘, **kwargs): ???for target in request.args.get(‘next‘), request.referrer: ???????if not target: ???????????continue ???????if is_safe_url(target): ???????????return redirect(target) ???return redirect(url_for(‘default‘, **kwargs))# AJAX ?点击按钮加载更多文本 ?@app.route(‘/post‘)def show_post(): ???post_body = generate_lorem_ipsum(n=2) ??# 生成两段随即文本 ???return ‘‘‘ ???<h1>A very long post</h1> ???<div class="body">%s</div> ???<button id="load">Load More</button> ???<script src="http://code.jquery.com/jquery-3.3.1.min.js"></script> ???<script type="text/javascript"> ???$(function(){ ???????$(‘#load‘).click(function(){ ???????????$.ajax({ ???????????????url:‘/more‘, ???????????????type:‘get‘, ???????????????success:function(data){ ???????????????????$(‘.body‘).append(data); ???????????????} ???????????}) ???????}) ???}) ???</script>‘‘‘ % post_body@app.route(‘/more‘)def load_post(): ???return generate_lorem_ipsum(n=1)flaskweb开发实战，入门进阶和原理解析第二章，http部分实例
原文地址：https://www.cnblogs.com/dairuiquan/p/10328129.html