Python Flask(一) –by Maxime Bouroumeau-Fuseau

来源：互联网发布：知善恶树英语编辑：程序博客网时间：2024/06/05 19:50

欢迎访问我的博客~地平线上的一匹狼-Python flask (一)
第一节的代码

# -*- coding: utf-8 -*-import sqlite3from flask import Flask, request, session, g, redirect, url_for,abort, render_template, flash, jsonify# configurationDATABASE = '/tmp/flaskr.db'DEBUG = TrueSECRET_KEY = 'development key'USERNAME = 'admin'PASSWORD = 'default'# create our little application :)app = Flask(__name__)app.config.from_envvar('FLASKR_SETTINGS', silent=True)app.config['SECRET_KEY']='F34TF$($e34D';@app.route('/_add_numbers')def add_numbers():    a=request.args.get('a',0,type=int)    b=request.args.get('b',0,type=int)    return jsonify(result=a+b)@app.route('/')def home():    return render_template('index.html')@app.route('/signup',methods=['POST'])def signup():    session['username']=request.form['username']    session['message']=request.form['message']    return redirect(url_for('message'))@app.route('/message')def message():    if not 'username' in session:        return abort(403)    return render_template('message.html',username=session['username'],message=session['message'])def connect_db():    return sqlite3.connect(app.config['DATABASE'])if __name__ == '__main__':    app.run()

在这个例子中,用户将输入想要说的信息到第一个页面,即用户和,message,这些数据将被存储在session中并且将被同步显示在/message页面下.

Some observations:
- app.config is a dict containing configuration parameters
- @app.route() is by default limited to GET requests. Allowed HTTP methods of an action can be specified using the methods keyword arg.
- url_for(route_name, **kwargs) should be used to generate urls for your handlers. It takes as first parameter the function name and as keyword args any needed parameters to generate the url.
- redirect(url) creates an HTTP response with a redirect code and location
- abort(http_code) is used to create error responses and stop the executing function.

Flask is natively integrated with jinja2, a very good templating engine. Templates should be saved as .html files under the templates/ folder. The render_template(filename, **kwargs) function is a pretty straightforward method to render them.
即render_template()函数接受任意多个参数,第一个参数是位于templates/下的模板文件,之后的参数均是模板文件内定义的数据.

然后我们使用jinja渲染html.代码如下

index.html:{% extends "layout.html" %}{% block content %}    <h1>Say something</h1>    <form method="post" action="{{ url_for('signup') }}">        <p><label>Username:</label> <input type="text" name="username" required></p>        <p><label>Message:</label> <textarea name="message"></textarea></p>        <p><button type="submit">Send</button></p>    </form>{% endblock %}message.html:{% extends "layout.html" %}{% block content %}    <h1>{{ username }} said:</h1>    <p>        {{ message }}    </p>    <a href="{{ url_for('home') }}">Say something else</a>{% endblock %}layout.html:<!doctype html><html lang="en">    <head>        <title>Say somthing</title>        <meta http-equiv="content-type" content="text/html; charset=utf-8">        <link rel="shortcut icon" href="{{ url_for('static', filename='favicon.ico') }}">    </head>    <body>        {% block content %}{% endblock %}    </body></html>

其中,模板中的url_for()是从 static/ 目录下get到当时路由定义函数渲染的页面.比如这里会转到index.html

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