Python Web框架Flask下网站开发入门实例

2019-11-25 18:00:06

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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

复制代码代码如下:

.
├── 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

复制代码代码如下:

#!/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

复制代码代码如下:

<!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

复制代码代码如下:

<!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

复制代码代码如下:

<!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

复制代码代码如下:

<!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>