Flask简介
基于python的web微框架, 只提供了一个稳健的核心, 其他功能全部是通过扩展实现的, 我们只需要学会各项扩展库的使用
Python 虚拟环境
是基于Python基础环境上虚拟出的一个工作环境, 目的是防止基础环境被污染, 便于项目对包的管理
虚拟环境管理方法
#### virtualenv
#### Virtualenvwrapper
#### conda
#### pipenv
安装
#### `pip install pipenv`
#### `pipenv install flask`
第一个应用
#!/usr/bin/env python
from flask import Flask
# 初始化
app = Flask(__name__)
@app.route('/')
def index():
return 'Hello World!'
if __name__ == '__main__':
app.run()
使用
#### `python app.py`
路由和视图函数
#!/usr/bin/env python
from flask import Flask
# 初始化
app = Flask(__name__)
@app.route('/')
def index():
return 'Hello World!'
@app.route('/a') ## 路由, 指向下面的视图函数
def add(): ## 视图函数
return '1 + 1 = 2'
# 路由也可以传值
@app.route('/user/<username>')
def user_index(username): ## 在视图函数中指明变量名称
return 'Hello {}' . format(username)
@app.route('/post/, <int: post_id>')
def show_post(post_id):
return 'Post {}' . format(post_id)
if __name__ == '__main__':
app.run(debug=True) ## 随时修改
URL重定向
url_for()
#### 构造动态的URL
*
##### url_for('函数名', 命名参数, 其它参数)
*
```python
#!/usr/bin/env python
from flask import Flask
from flask import url_for
from flask import redirect
# 初始化
app = Flask(__name__)
@app.route('/')
def index():
return 'Hello World!'
@app.route('/a') ## 路由, 指向下面的视图函数
def add(): ## 视图函数
return '1 + 1 = 2'
# 路由也可以传值
@app.route('/user/<username>')
def user_index(username): ## 在视图函数中指明变量名称
return 'Hello {}' . format(username)
@app.route('/post/, <int: post_id>')
def show_post(post_id):
return 'Post {}' . format(post_id)
@app.route('/test')
def test():
print(url_for('index'))
print(url_for('user_index', username = 'xxx'))
print(url_for('show_post', post_id = 1))
return 'test'
@app.route('/<username>')
def hello(username):
if username == 'handsomexxx':
return f'Hello {username}'
else:
return redirect(url_for('index'))
if __name__ == '__main__':
app.run(debug=True) ## 随时修改
```
模版渲染
render_template
```python
#!/usr/bin/env python
from flask import Flask
from flask import url_for
from flask import redirect
from flask import render_template
# 初始化
app = Flask(__name__)
@app.route('/')
def index():
return 'Hello World!'
@app.route('/a') ## 路由, 指向下面的视图函数
def add(): ## 视图函数
return '1 + 1 = 2'
# 路由也可以传值
@app.route('/user/<username>')
def user_index(username): ## 在视图函数中指明变量名称
return render_template('user_index.html', username = username) ## 模版渲染
@app.route('/post/, <int: post_id>')
def show_post(post_id):
return 'Post {}' . format(post_id)
@app.route('/test')
def test():
print(url_for('index'))
print(url_for('user_index', username = 'xxx'))
print(url_for('show_post', post_id = 1))
return 'test'
@app.route('/<username>')
def hello(username):
if username == 'handsomexxx':
return f'Hello {username}'
else:
return redirect(url_for('index'))
if __name__ == '__main__':
app.run(debug=True) ## 随时修改
```
```html
<h1> hello, {{ username }}! </h1>
```
get 和 post
GET
#!/usr/bin/env python
from flask import request
from flask import Flask
# 初始化
app = Flask(__name__)
@app.route('/user/<password>'):
def user_password(password):
print('User-Agent: ', request.headers.get('User-Agent'))
print('time: ', request.args.get('time'))
print('q: ', request.args.get('q'))
print('issingle: '. request.args.get('issingle'))
return f'password is {password}'
if __name__ == '__main__':
app.run(debug=True) ## 随时修改
POST
#!/usr/bin/env python
from flask import request
from flask import Flask
# 初始化
app = Flask(__name__)
@app.route('/register', method = ['GET', 'POST'])
def register():
print('method: ', request.method)
print('name', request.form['name'])
print('password', request.from.get('password'))
pritn('hobbies: ', request.form.getlist('hobbies'))
print('age: ', request.form.get('age', default = 18))
return 'register successd!'
if __name__ == '__main__':
app.run(debug=True) ## 随时修改
#!/usr/bin/env python
import requests
# 设置需要发送的数据
user_info = {'name': 'xxx', 'password': '123', 'hobbies': ['code', 'game', 'run']}
# 向URL发送POST请求
r = requests.post('http://127.0.0.1:5000/register', data = user_info)
print(r.text)
session 和 cookie
SESSION
#!/usr/bin/env python
from flask import session
from flask import Flask
# 初始化
app = Flask(__name__)
# 不使用安全码, 浏览器会报错
app.secret_key = 'adadhjkhajhh'
@app.route('/set_session')
def set_session():
## 设置session的持久化
session.permanent = True
session['username'] = 'xxx'
return '成功设置 session'
@app.route('/get_session')
def get_session():
value = session.get('username')
return f'成功获取session值为 {value}'
if __name__ == '__main__':
app.run(debug=True) ## 随时修改
COOKIE
#!/usr/bin/env python
from flask import Flask
from flask import make_response
# 初始化
app = Flask(__name__)
@app.route('/user/<username>')
def user_index(username): ## 在视图函数中指明变量名称
if username == 'invalid':
abort(404)
return render_template('user_index.html')
# 不使用安全码, 浏览器会报错
app.secret_key = 'adadhjkhajhh'
@app.route('/set_session')
def set_session():
## 设置session的持久化
session.permanent = True
session['username'] = 'xxx'
return '成功设置 session'
@app.route('/get_session')
def get_session():
value = session.get('username')
return f'成功获取session值为 {value}'
@app.route('set_cookie')
def set_cookie(username):
resp = make_response(render_template('user_index.html', username = username))
resp.set_cookie('username', username)
return resp
@app.route('/get_cookie')
def get_cookie():
username = request.cookies.get('username')
return f'Hello {username}'
#@app.errorhandler(404)
#def not_found(error):
# return render_template('404.html'), 404
if __name__ == '__main__':
app.run(debug = True)
<h1>error!</h1>