flask的基本使用2

上一篇我们介绍了基本使用方法

flask使用

【 1 】基本使用

from flask import Flask# 1 实例化得到对象
app = Flask(__name__)# 2 注册路由--》写视图函数
@app.route('/')
def index():# 3 返回给前端字符串return 'hello world'if __name__ == '__main__':# 运行app，默认运行在5000app.run()app.run(host='0.0.0.0',port=8080)

【 2 】watchdog使用

pip3 install watchdog

# pip3 install watchdog
# 当前目录下文件修改会被监控到，打印日志
import sys
import time
import logging
from watchdog.observers import Observer
from watchdog.events import LoggingEventHandlerif __name__ == "__main__":logging.basicConfig(level=logging.INFO,format='%(asctime)s - %(message)s',datefmt='%Y-%m-%d %H:%M:%S')path = sys.argv[1] if len(sys.argv) > 1 else '.'event_handler = LoggingEventHandler()observer = Observer()observer.schedule(event_handler, path, recursive=True)observer.start()try:while True:time.sleep(1)except KeyboardInterrupt:observer.stop()observer.join()

运行项目方式

-方式一（pycharm配置）：-新建一个flask-server---》配置选中 script---》有app的文件-方式二：命令（推荐这种）flask --app py文件名字  runflask --app 5-flask再体验.py run-方式三：命令python38 -m flask --app py文件名字 runpython38 -m flask --app 5-flask再体验.py run-方式四，右键运行if __name__ == '__main__':app.run()-方式五：命令运行（跟右键运行一样）python38 5-app.py- 方式6：少用（pip install python-dotenv）flask app run

【 3 】python-dotenv

注意添加一个.env文件里面

# pip3 install python-dotenv
import os
from dotenv import load_dotenv
from dotenv import dotenv_values
## 1 加载配置文件
# 必须在根路径下新建一个 .env 的文件，并写入配置才能返回True,会把.env下的配置文件设置进环境变量
# res=load_dotenv()  # take environment variables from .env
# print(res)
# print(os.environ.get('DOMAIN'))
# print(os.environ.get('NAME'))
# print(os.environ.get('AGE'))
# You will probably want to add .env to your .gitignore, especially if it contains secrets like a password.
## 2 获取环境变量字典
print(config)  # OrderedDict([('DOMAIN', 'https://ent.cri.cn/star/photo'), ('NAME', 'jing'), ('HOBBY', 'raw')])
print(config.get('DOMAIN'))
print(config.get('NAME'))
print(config.get('HOBBY'))

【 5 】虚拟环境

# 之前咱们学过适应第三方模块创建虚拟环境
# python内置（venv）可以直接创建虚拟环境Use a virtual environment to manage the dependencies for your project, both in development and in production.
# 在开发和生产中,使用虚拟环境来管理项目的依赖关系What problem does a virtual environment solve? The more Python projects you have, the more likely it is that you need to work with different versions of Python libraries, or even Python itself. Newer versions of libraries for one project can break compatibility in another project.
# 虚拟环境解决什么问题？您拥有的 Python 项目越多，您就越有可能需要使用不同版本的 Python 库，甚至是 Python 本身。一个项目的较新版本的库可能会破坏另一项目的兼容性。Virtual environments are independent groups of Python libraries, one for each project. Packages installed for one project will not affect other projects or the operating system’s packages.
# 虚拟环境是一组独立的 Python 库，每个项目对应一个。为一个项目安装的软件包不会影响其他项目或操作系统的软件包Python comes bundled with the venv module to create virtual environments.
# Python 使用 venv 模块来创建虚拟环境###### Mac/linux
# 创建虚拟环境
mkdir myproject
cd myproject
python3 -m venv .venv# 激活虚拟环境
. .venv/bin/activate####Win
# 创建虚拟环境
mkdir myproject
cd myproject
py -3 -m venv .venv
# 激活虚拟环境
.venv\Scripts\activate

【 6 】debug

flask --app 5-app.py run --debugflask --app  "app名字.py" run --debugflask --app "基本使用flask.py" run --debug 
# 1 浏览器显示错误信息
# 2 改了代码自动重启

【三】fastapi

# from typing import Union  # python 的内置--》数据校验
import timefrom fastapi import FastAPI
import asyncioapp = FastAPI()@app.get("/")
async def read_root():# 如果有ioawait asyncio.sleep(2)# time.sleep(10)return {"Hello": "World"}@app.get("/items/{item_id}")
def read_item(item_id, q=None):return {"item_id": item_id, "q": q}# 天生自带接口文档----》方便我们快速写前后端分离的接口# uvicorn 7-fast-api初体验:app# 针对于io多的web后端，使用 异步框架，会提高性能
# 咱们项目，基本都是io多，查询数据库，redis 都是io操作
# 使用fastapi能提高并发量

【四】登陆案例

app.py
html文件要在templates文件下

from flask import Flask, render_template, request, redirectapp = Flask(__name__)@app.route('/login', methods=['GET', 'POST'])
def login():if request.method == 'GET':# 返回模板return render_template('login.html')else:# 取出用户名密码，判断# flask的request 没有POST，GET# request.form  就是 post# request.args  就是 GETusername = request.form.get('username')password = request.form.get('password')if username == 'jing' and password == '123':# 重定向到百度return redirect('https://www.baidu.com')else:return render_template('login.html', error='用户名密码错误')if __name__ == '__main__':app.run(debug=True)

<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>登录</title>
</head>
<body>
<form method="post"><p>用户名： <input type="text" name="username"></p><p>密码： <input type="password" name="password"></p><input type="submit" value="登陆"> {{error}}</form>
</body>
</html>

第二个版本
app.py

from flask import Flask, render_template, request, redirect, session, jsonify# html(rander_template)  jsonify(响应格式)
app = Flask(__name__, template_folder="templates", static_folder="static")
app.secret_key = 'sdasudgiguasdb'  # 如果使用session，必须加秘钥# 用户信息
USERS = {1: {'name': '刘亦菲', 'age': 18, 'gender': '男','text': "刘亦菲，1987年8月25日出生于湖北省武汉市，华语影视女演员、歌手，毕业于北京电影学院2002级表演系本科",'img': 'https://img2.woyaogexing.com/2021/10/16/e3ccba623848430ba83209c0621a2256!400x400.jpeg'},2: {'name': '彭于晏', 'age': 28, 'gender': '男','text': "彭于晏，1982年3月24日出生于中国台湾省澎湖县，毕业于不列颠哥伦比亚大学，华语影视男演员。。。。。。。。",'img': 'https://img2.woyaogexing.com/2021/10/16/e71aa35728c34313bccb4c371192990f!400x400.jpeg'},3: {'name': '迪丽热巴', 'age': 38, 'gender': '女','text': "迪丽热巴（Dilraba），1992年6月3日出生于中国新疆乌鲁木齐市，毕业于上海戏剧学院，中国内地影视女演员",'img': 'https://img2.woyaogexing.com/2021/10/30/6a34146dde2d4f1c832463a5be1ed027!400x400.jpeg'},4: {'name': '亚瑟', 'age': 38, 'gender': '男','text': "亚瑟，是腾讯手游《王者荣耀》中一名战士型英雄角色，也是《王者荣耀》的新手英雄之一，既可攻又可守",'img': 'https://img2.woyaogexing.com/2021/10/30/371b2aa7a03c4f53b7b1bc86f877d7d1!400x400.jpeg'},
}# 加入装饰器
from functools import wraps# 用户登陆，写个装饰器
def login_required(func):def inner(*args, **kwargs):if session.get('username'):res = func(*args, **kwargs)return reselse:return redirect('/login')return inner@app.route('/',endpoint='/')
@login_required
def index():# 7 判断用户是否登录，如果登录了，返回模板if session.get('username'):# 1 返回模板，渲染到模板中return render_template('index.html', user_dict=USERS)@app.route('/login', methods=['GET', 'POST'])def login():# 2 判断是get请求还是post请求，需要使用request对象## 2.1 request 正常每次请求都是新的request---》现在flask中全局就一个request--》它会不会乱套？if request.method == 'GET':return render_template('login1.html')else:# 3 取出用户名密码--》请求对象中取--》requestusername = request.form.get('username')password = request.form.get('password')if username == 'jing' and password == '123123':# 6 登录成功--》登录信息写入cookie--》使用session写入session['username'] = username# 4 登录成功--》重定向到 indexreturn redirect('/')else:# 5 登录失败--》返回login.html 页面，但是页面中渲染错误信息return render_template('login1.html', error='用户名密码错误')@app.route('/detail/<int:pk>', methods=['GET'],endpoint='detail')
@login_required
def detail(pk):if session.get('username'):user = USERS.get(pk)return render_template('detail.html', info=user)@app.route('/demo01', methods=['GET'])
def demo01():request.argsreturn jsonify({'code': 100, 'msg': '成功'})if __name__ == '__main__':app.run()

login1.html

<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha1/dist/css/bootstrap.min.css"><title>登录</title>
</head>
<body>
<div class="container col-xl-10 col-xxl-8 px-4 py-5"><div class="row align-items-center g-lg-5 py-5"><div class="col-lg-7 text-center text-lg-start"><h1 class="display-4 fw-bold lh-1 mb-3">亚洲最大交友平台</h1><p class="col-lg-10 fs-4">Bootstrap是Twitter推出的一个用于前端开发的开源工具包。它由Twitter的设计师MarkOtto和Jacob Thornton合作开发,是一个CSS/HTML框架。目前,Bootstrap最新版本为5.0</p></div><div class="col-md-10 mx-auto col-lg-5"><form class="p-4 p-md-5 border rounded-3 bg-light" method="post"><div class="form-floating mb-3"><input type="text" class="form-control" id="floatingInput" placeholder="name@example.com" name="username"><label for="floatingInput">用户名</label></div><div class="form-floating mb-3"><input type="password" class="form-control" id="floatingPassword" placeholder="Password" name="password"><label for="floatingPassword">密码</label></div><div class="checkbox mb-3"><label><input type="checkbox" value="remember-me"> 记住密码</label></div><button class="w-100 btn btn-lg btn-primary" type="submit">登录</button><hr class="my-4"><small class="text-muted">{{error}}</small></form></div></div>
</div>
</body>
</html>

detail.html

<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha1/dist/css/bootstrap.min.css"><script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha1/dist/js/bootstrap.bundle.min.js"></script><title>Title</title>
</head>
<body>
<div class="container"><div class="sticky-top"><header class="d-flex flex-wrap justify-content-center py-3 mb-4 border-bottom"><a href="/" class="d-flex align-items-center mb-3 mb-md-0 me-md-auto text-dark text-decoration-none"><svg class="bi me-2" width="40" height="32"><use xlink:href="#bootstrap"></use></svg><span class="fs-4">交友平台</span></a><ul class="nav nav-pills"><li class="nav-item"><a href="#" class="nav-link active" aria-current="page">首页</a></li><li class="nav-item"><a href="#" class="nav-link">女生</a></li><li class="nav-item"><a href="#" class="nav-link">男生</a></li><li class="nav-item"><a href="#" class="nav-link">国产</a></li><li class="nav-item"><a href="#" class="nav-link">欧美</a></li></ul></header></div><div class="position-relative overflow-hidden p-3 p-md-5 m-md-3 text-center bg-light"><div class="col-md-5 p-lg-5 mx-auto my-5"><h1 class="display-4 fw-normal">{{info.name}}</h1><img src="{{info.img}}" alt=""width="300px" height="300px" style="margin: 20px"><p class="lead fw-normal">{{info.text}}</p><a class="btn btn-outline-secondary" href="#">收藏</a></div><div class="product-device shadow-sm d-none d-md-block"></div><div class="product-device product-device-2 shadow-sm d-none d-md-block"></div></div><div><footer class="py-3 my-4"><ul class="nav justify-content-center border-bottom pb-3 mb-3"><li class="nav-item"><a href="#" class="nav-link px-2 text-muted">首页</a></li><li class="nav-item"><a href="#" class="nav-link px-2 text-muted">特性</a></li><li class="nav-item"><a href="#" class="nav-link px-2 text-muted">联系我们</a></li><li class="nav-item"><a href="#" class="nav-link px-2 text-muted">资料获取</a></li><li class="nav-item"><a href="#" class="nav-link px-2 text-muted">关于</a></li></ul><p class="text-center text-muted">Copyright © 1998 - 2029 liuqingzheng. All Rights Reserved. </p></footer></div></div>
</body>
</html>

index.html

<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha1/dist/css/bootstrap.min.css"><script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha1/dist/js/bootstrap.bundle.min.js"></script><title>Title</title>
</head>
<body>
<div class="container"><!--    头部--><div class="sticky-top"><header class="d-flex flex-wrap justify-content-center py-3 mb-4 border-bottom"><a href="/" class="d-flex align-items-center mb-3 mb-md-0 me-md-auto text-dark text-decoration-none"><svg class="bi me-2" width="40" height="32"><use xlink:href="#bootstrap"></use></svg><span class="fs-4">交友平台</span></a><ul class="nav nav-pills"><li class="nav-item"><a href="#" class="nav-link active" aria-current="page">首页</a></li><li class="nav-item"><a href="#" class="nav-link">女生</a></li><li class="nav-item"><a href="#" class="nav-link">男生</a></li><li class="nav-item"><a href="#" class="nav-link">国产</a></li><li class="nav-item"><a href="#" class="nav-link">欧美</a></li></ul></header></div><!--轮播图--><div><div class="bd-example-snippet bd-code-snippet"><div class="bd-example"><div id="carouselExampleCaptions" class="carousel slide" data-bs-ride="carousel"><div class="carousel-indicators"><button type="button" data-bs-target="#carouselExampleCaptions" data-bs-slide-to="0" class=""aria-label="Slide 1"></button><button type="button" data-bs-target="#carouselExampleCaptions" data-bs-slide-to="1"aria-label="Slide 2" class="active" aria-current="true"></button><button type="button" data-bs-target="#carouselExampleCaptions" data-bs-slide-to="2"aria-label="Slide 3" class=""></button></div><div class="carousel-inner"><div class="carousel-item"><img src="https://img.zcool.cn/community/01fb5458fedf57a801214550f9677a.jpg@2o.jpg" alt=""width="100%" height="300"><div class="carousel-caption d-none d-md-block"><h5>激情绿荫</h5><p>Some representative placeholder content for the first slide.</p></div></div><div class="carousel-item active"><img src="https://img2.baidu.com/it/u=2951612437,4135887500&fm=253&fmt=auto&app=138&f=JPEG"alt="" width="100%" height="300"><div class="carousel-caption d-none d-md-block"><h5>品牌雨伞</h5><p>Some representative placeholder content for the second slide.</p></div></div><div class="carousel-item"><img src="https://img1.baidu.com/it/u=1417689082,3333220267&fm=253&fmt=auto&app=138&f=JPEG"alt="" width="100%" height="300"><div class="carousel-caption d-none d-md-block"><h5>家装节</h5><p>Some representative placeholder content for the third slide.</p></div></div></div><button class="carousel-control-prev" type="button" data-bs-target="#carouselExampleCaptions"data-bs-slide="prev"><span class="carousel-control-prev-icon" aria-hidden="true"></span><span class="visually-hidden">Previous</span></button><button class="carousel-control-next" type="button" data-bs-target="#carouselExampleCaptions"data-bs-slide="next"><span class="carousel-control-next-icon" aria-hidden="true"></span><span class="visually-hidden">Next</span></button></div></div></div></div><!--    内容--><div class="row row-cols-md-2" style="padding: 10px">{% for k,v in user_dict.items() %}<div class="card"><div class="row " style="padding: 10px"><img src="{{v.get('img')}}" alt="" class="col-md-4"><div class="col-md-8"><div class="card-body"><h5 class="card-title">{{v['name']}}</h5><p class="card-text">性别：{{v.gender}}</p><p class="card-text">年龄：{{v.age}}</p><p class="card-text"><a href="/detail/{{k}}" class="btn btn-danger">查看详细</a></p></div></div></div></div>{%endfor%}</div><!--    table--><div class="bd-example" style="margin-top: 30px"><table class="table table-hover table-striped table-bordered"><thead><tr class="table-danger"><th colspan="3" class="text-center">更多交友</th></tr></thead><tbody><tr class="table-success"><th>杨幂</th><td>女</td><td>33</td></tr><tr class="table-warning"><th scope="row">刘亦菲</th><td>未知</td><td>40</td></tr><tr class="table-success"><th scope="row">彭于晏</th><td>男</td><td>23</td></tr><tr class="table-warning"><th scope="row">陈奕迅</th><td>男</td><td>44</td></tr><tr class="table-success"><th scope="row">薛之谦</th><td>男</td><td>36</td></tr><tr class="table-warning"><th>李清照</th><td>女</td><td>未知</td></tr></tbody></table></div><!--分页--><div class="d-flex justify-content-center"><ul class="pagination pagination-lg"><li class="page-item"><a class="page-link" href="#" aria-label="Previous"><span aria-hidden="true">«</span></a></li><li class="page-item"><a class="page-link" href="#">1</a></li><li class="page-item"><a class="page-link" href="#">2</a></li><li class="page-item"><a class="page-link" href="#">3</a></li><li class="page-item"><a class="page-link" href="#">4</a></li><li class="page-item"><a class="page-link" href="#">5</a></li><li class="page-item"><a class="page-link" href="#">6</a></li><li class="page-item"><a class="page-link" href="#" aria-label="Next"><span aria-hidden="true">»</span></a></li></ul></div><!--    尾部--><div><footer class="py-3 my-4"><ul class="nav justify-content-center border-bottom pb-3 mb-3"><li class="nav-item"><a href="#" class="nav-link px-2 text-muted">首页</a></li><li class="nav-item"><a href="#" class="nav-link px-2 text-muted">特性</a></li><li class="nav-item"><a href="#" class="nav-link px-2 text-muted">联系我们</a></li><li class="nav-item"><a href="#" class="nav-link px-2 text-muted">资料获取</a></li><li class="nav-item"><a href="#" class="nav-link px-2 text-muted">关于</a></li></ul><p class="text-center text-muted">Copyright © 1998 - 2029 liuqingzheng. All Rights Reserved. </p></footer></div>
</div>
</body>
</html>

装饰器

只需要添加在路由下面即可

@app.route('/detail/<int:pk>', methods=['GET'],endpoint='detail')
@login_required
def detail(pk):if session.get('username'):user = USERS.get(pk)return render_template('detail.html', info=user)

问题一：登录装饰器，放上还是下  放下面问题二：每个路由有个别名【反向解析】--》这个别名如果不写--》会以函数名作为别名--》一旦加了登录认证装饰器，所有别名都变成了 inner

# 1 使用装饰器装饰装饰器  @wraps(func)
# 2 每个人都指定别名

def login_required(func):def inner(*args, **kwargs):if session.get('username'):res = func(*args, **kwargs)return reselse:return redirect('/login')return inner

【五】配置文件

django中配置文件用的是： settings.py

-实际开发中用了两套配置文件
主要用方式三跟方式四
print(app.config) 默认配置项

<Config {'DEBUG': False, 'TESTING': False, 'PROPAGATE_EXCEPTIONS': None, 'SECRET_KEY': None, 'PERMANENT_SESSION_LIFETIME': datetime.timedelta(days=31), 'USE_X_SENDFILE': False, 'SERVER_NAME': None, 'APPLICATION_ROOT': '/', 'SESSION_COOKIE_NAME': 'session', 'SESSION_COOKIE_DOMAIN': None, 'SESSION_COOKIE_PATH': None, 'SESSION_COOKIE_HTTPONLY': True, 'SESSION_COOKIE_SECURE': False, 'SESSION_COOKIE_SAMESITE': None, 'SESSION_REFRESH_EACH_REQUEST': True, 'MAX_CONTENT_LENGTH': None, 'SEND_FILE_MAX_AGE_DEFAULT': None, 'TRAP_BAD_REQUEST_ERRORS': None, 'TRAP_HTTP_EXCEPTIONS': False, 'EXPLAIN_TEMPLATE_LOADING': False, 'PREFERRED_URL_SCHEME': 'http', 'TEMPLATES_AUTO_RELOAD': None, 'MAX_COOKIE_SIZE': 4093}>

flask中的配置文件是一个flask.config.Config对象（继承字典）,默认配置为：{'DEBUG':                                get_debug_flag(default=False),  是否开启Debug模式'TESTING':                              False,                          是否开启测试模式'PROPAGATE_EXCEPTIONS':                 None,                          'PRESERVE_CONTEXT_ON_EXCEPTION':        None,'SECRET_KEY':                           None,'PERMANENT_SESSION_LIFETIME':           timedelta(days=31),'USE_X_SENDFILE':                       False,'LOGGER_NAME':                          None,'LOGGER_HANDLER_POLICY':               'always','SERVER_NAME':                          None,'APPLICATION_ROOT':                     None,'SESSION_COOKIE_NAME':                  'session','SESSION_COOKIE_DOMAIN':                None,'SESSION_COOKIE_PATH':                  None,'SESSION_COOKIE_HTTPONLY':              True,'SESSION_COOKIE_SECURE':                False,'SESSION_REFRESH_EACH_REQUEST':         True,'MAX_CONTENT_LENGTH':                   None,'SEND_FILE_MAX_AGE_DEFAULT':            timedelta(hours=12),'TRAP_BAD_REQUEST_ERRORS':              False,'TRAP_HTTP_EXCEPTIONS':                 False,'EXPLAIN_TEMPLATE_LOADING':             False,'PREFERRED_URL_SCHEME':                 'http','JSON_AS_ASCII':                        True,'JSON_SORT_KEYS':                       True,'JSONIFY_PRETTYPRINT_REGULAR':          True,'JSONIFY_MIMETYPE':                     'application/json','TEMPLATES_AUTO_RELOAD':                None,}# 3 修改默认# 方式一：直接在app上改，实际他们在config属性上（开发阶段用）app.debug=Trueapp.secret_key='asdfasdf'# 方式二：通过app.config改--》celery就是这样app.config['DEBUG']=Trueapp.config['SECRET_KEY']='aaaa'# 方式三：app.config.from_pyfile("python文件名称")--跟django一样1 写一个 settings.py2 app.config.from_pyfile('settings.py')# 方式四：app.config.from_object('settings.TestingConfig')class Config(object):DEBUG = FalseTESTING = FalseDATABASE_URI = '127.0.0.1'DATABASE_PORT = 3306class ProductionConfig(Config):DATABASE_URI = '192.168.1.11'DATABASE_PORT = 3308class DevelopmentConfig(Config):DEBUG = True# 方式其他：app.config.from_envvar("环境变量名称")app.config.from_json("json文件名称") app.config.from_mapping({'DEBUG': True}) #可能会用- 配置中心---》服务--》有个地址，发送请求会返回一对json格式配置文件-nocos# dotenv的使用# 4 设置自己（跟修改默认一样）-app.config['DB_PASSWORD']='lqz123'

from flask import Flask, jsonify# 1 实例化得到对象
app = Flask(__name__)
# ## 方式一
# app.debug=True
# app.secret_key='asdfasdf'
# 
# ## 方式二
# app.config['DEBUG']=True
# app.config['SECRET_KEY']='aaaa'## 方式三
# app.config.from_pyfile('settings.py')## 方式四
# app.config.from_object('settings.ProductionConfig')print(app.config)
''''''# 2 注册路由--》写视图函数
@app.route('/')
def index():# 3 返回给前端字符串return 'hello world'@app.errorhandler(404)
def error_404(arg):return jsonify({'code': 'xxx'})@app.errorhandler(500)
def error_500(arg):return jsonify({'code': '500错误了'})if __name__ == '__main__':# 运行app，默认运行在5000app.run()# app.run(host='0.0.0.0',port=8080)