Python Web框架Flask下网站开发入门实例

一、Flask简介

Flask 是一个 Python 实现的 Web 开发微框架。官网：http://flask.pocoo.org/

二、Demo

1、代码结构

. ├── blog.py ├── static │ ├── css │ │ └── index.css │ ├── images │ │ ├── cat.jpg │ │ └── sheying1229.jpg │ └── js └── templates ├── index.html ├── login.html ├── regist.html └── upload.html

5 directories, 8 files

2、主程序blog.py


#!/usr/bin/python

#coding:utf8
from flask import Flask, render_template, url_for, request,redirect,make_response,session

import os,MySQLdb
app = Flask(__name__)

app.secret_key='afjlsjfowflajflkajfkjfkaljf'

user_list = ['jim','max','py']
imagepath = os.path.join(os.getcwd(),"static/images")
@app.route('/')

def index():

    username = request.cookies.get('username')

    if not username:

        username = u'请先登录'

    islogin = session.get('islogin')

    nav_list = [u'首页',u'经济',u'文化',u'科技',u'娱乐']

    blog = {'title':'welcome to my blog','content':'hello, welcome to my blog.'}

    blogtag = {'javascript':10,"python":20,"shell":5}

    img = url_for('static', filename="images/cat.jpg")

    return render_template('index.html', nav_list=nav_list, username=username, blog = blog, blogtag = blogtag, img=img, islogin=islogin)
@app.route('/reg', methods=['GET','POST'])

def regist():

    if request.method == 'POST':

        username = request.form['username']

        conn = MySQLdb.connect(user='root',passwd='admin',host='127.0.0.1')

        conn.select_db('blog')

        curr = conn.cursor()

        sql = 'insert into `user` (`id`,`username`) values (%d,"%s")' % (1,username)

        curr.execute(sql)

        conn.commit()

        curr.close()

        conn.close()

        return "user %s regist ok!" % request.form['username']

    else:

        #request.args['username']

        return render_template('regist.html')
@app.route('/upload', methods=['GET','POST'])

def upload():

    if request.method == 'POST':

        username = request.form['username']

        file = request.files['img']

        filename = file.filename

        file.save(os.path.join(imagepath,filename))

        return "<img src='static/images/%s' alt=''/>" % filename

    else:

        return render_template('upload.html')
@app.route('/login/', methods=['GET','POST'])

def login():

    if request.method == 'POST':

        username = request.form.get('username')

        if username in user_list:

            response = make_response(redirect('/'))

            response.set_cookie('username', value=username, max_age=300)

            session['islogin'] = '1'

            return response

        else:

            session['islogin'] = '0'

            return redirect('/login/')

    else:

        return render_template('login.html')
if __name__ == '__main__':

    app.run(debug=True,host='0.0.0.0',port=5000)

主要有首页、注册、登录、上传页面。

blog.py主要是展示了Flask中常见功能用法：路由，数据库操作，cookie，session，redirect，表单，文件上传，调试，Web服务器的IP和端口，静态文件读取等。

3、首页模板index.html


<!DOCTYPE html>

<html>

<head>

    <meta charset="utf-8"/>

    <title>Flask DEMO</title>

    <link rel="stylesheet" type="text/css" href="static/css/index.css"/>

</head>

<body>

    <div class="header">

        {%if islogin == '1' %}

        <h1>Welcome ,{{username}}!</h1>

        {%else%}

        <h1>{{username}}!</h1>

        {%endif%}

        <div class="nav">

            <ul>

                {%for nav in nav_list%}

                <li><a href="{{nav}}">{{nav}}</a></li>

                {%endfor%}

            </ul>

        </div>

    </div>

    <div class="container">

        <div class="item">

            <h1>{{blog['title']}}</h1>

            <div class="content">

                <img src="/static/images/cat.jpg" alt="cat" />

                <p>{{blog['content']}}</p>

                <img src="{{img}}" alt="cat" />

            </div>

        </div>

        <div class="side">

            <ul>

                {%for key,value in blogtag.items()%}

                    <li>{{key}}({{value}})</li>

                {%endfor%}

            </ul>

        </div>

    </div>

</body>

</html>

这个模板主要展示了在Flask模板中如何读取各种类型的变量。

4、登录页面login.html


<!DOCTYPE html>

<html>

<head>

    <meta charset="utf-8"/>

    <title>Login</title>

    <link rel="stylesheet" type="text/css" href="static/css/index.css"/>

</head>

<body>

    <div class="header">

        <h1>Login</h1>

    </div>

    <div class="container">

        <div class="item">

            <form action="" method="post">

                <input type="text" placeholder="please input username" name="username" /><br/>

                <input type="submit" value="Login"/>

            </form>

        </div>

    </div>

</body>

</html>

结合blog.py主要展示表单如何提交取值，cookie和session应用。

5、注册页面regist.html


<!DOCTYPE html>

<html>

<head>

    <meta charset="utf-8"/>

    <title>Regist</title>

    <link rel="stylesheet" type="text/css" href="static/css/index.css"/>

</head>

<body>

    <div class="header">

        <h1>Regist</h1>

    </div>

    <div class="container">

        <div class="item">

            <form action="" method="post">

                <input type="text" placeholder="please input username" name="username" /><br/>

                <input type="submit" value="Regist"/>

            </form>

        </div>

    </div>

</body>

</html>

结合blog.py主要展示了数据库操作。

6、上传页面upload.html


<!DOCTYPE html>

<html>

<head>

    <meta charset="utf-8"/>

    <title>Upload</title>

    <link rel="stylesheet" type="text/css" href="static/css/index.css"/>

</head>

<body>

    <div class="header">

        <h1>Upload</h1>

    </div>

    <div class="container">

        <div class="item">

            <form action="" method="post" enctype="multipart/form-data">

                <input type="text" name="username" /><br/>

                <input type="file" name="img" /><br/>

                <input type="submit" value="Upload"/>

            </form>

        </div>

    </div>

</body>

</html>

结合blog.py主要展示了如何上传文件。

7、运行效果

基础教程