FLASK | 学习笔记（最简单的web程序、路由、请求-响应、flask_script 、livereload ）

最新推荐文章于 2024-04-10 09:33:43 发布

原创最新推荐文章于 2024-04-10 09:33:43 发布 · 278 阅读

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本文是一篇关于FLASK框架的学习笔记，涵盖了最简单的web程序创建、路由设置、请求-响应机制，以及如何使用flask_script和livereload进行便捷开发。通过阅读，你将了解到如何编写app.py、创建模板如hello.html、login.html、upload.html，以及404错误页面，并且掌握样式文件site.css的使用。同时，还会指导你如何生成项目依赖的requirements.txt文件。

app .py

from flask import Flask,render_template,request,redirect,url_for,make_response,abort
from flask_bootstrap import Bootstrap
from werkzeug.routing import BaseConverter
from werkzeug.utils import secure_filename
from flask_script import Manager
from os import path


class RegexConverter(BaseConverter):
    def __init__(self, url_map, *items):
        super(RegexConverter,self).__init__(url_map)
        self.regex = items[0]


app = Flask(__name__)
app.url_map.converters['regex'] = RegexConverter
app.config['DEBUG'] = True
manager = Manager(app)
bootstrap = Bootstrap(app)


@app.route('/')
def hello_world():
    response = make_response(render_template('hello.html',line1='eaa'))
    response.set_cookie('username', '')
    return response


@app.route('/services')
def services():
    return 'Services'


@app.route('/about')
def about():
    return 'About'


@app.route('/user/<regex("[a-z]{3}"):user_id>')
def user(user_id):
    return 'User %s' % user_id


@app.route('/login',methods=['GET','POST'])
def login():
    if request.method == 'POST':
        username = request.form['username']
        password = request.form['password']
    else:
        # http://127.0.0.1:5000/login?username=ray
        username = request.args['username']
    return render_template('login.html',method=request.method)


@app.route('/upload',methods=['GET','POST'])
def upload():
    if request.method == 'POST':
        f = request.files['file']
        basepath = path.abspath(path.dirname(__file__))
        upload_path = path.join(basepath, 'static', 'uploads', secure_filename(f.filename))
        f.save(upload_path)
        return redirect(url_for('upload'))
    return render_template('upload.html')


@app.errorhandler(404)
def page_not_found(error):
    return render_template('404.html'), 404


@manager.command
def dev():
    from livereload import Server
    live_server = Server(app.wsgi_app)
    live_server.watch('**/*.*')  # 监测整个项目所有文件变化。可以加参数，不加就整个项目重加载，加的话就执行方法里的内容。
    live_server.serve(open_url=True)


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

hello.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <link rel="stylesheet" href="{{ url_for('static', filename='site.css') }}" />
</head>
<body>
    <h1>{{ line1 }}</h1>
    <nav>
        <a href="{{ url_for('.services') }}">Services</a>
        <a href="{{ url_for('.about') }}">About</a>
    </nav>
</body>
</html>

login.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<h1>HTTP 方法：{{ method }}</h1>
<form method="post">
    <div>
        <input type="text" placeholder="username">
    </div>
    <div>
        <input type="password" placeholder="password">
    </div>
    <input type="submit">
</form>
</body>
</html>

upload.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<h1>文件上传示例</h1>

<form action=""
      method=post
      enctype="multipart/form-data">
    <p><input type="file" name="file">
        <input type="submit" value="Upload"></p>
</form>
</body>
</html>

404.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
<h1>404 </h1>
<h2>很抱歉！</h2>
<p>您访问的页面并不存在</p>
</body>
</html>

site.css

body{
    color:#efefef;
}

a,a:visited{
    color:#000;
}

生成requirements.txt

pip freeze > requirements.txt

pip install -r requirements.txt