Flask 框架基础知识笔记
Flask 基础◆CheckBox 复选框◆ HTML index.html<body>
<form action="/" method="post">
<div class="MyDiv">
<label>
<input type="checkbox" name="s_option" value="basketball" > 篮球
</label>
<label>
<input type="checkbox" name="s_option" value="football" > 足球
</label>
<label>
<input type="checkbox" name="s_option" value="badminton" > 羽毛球
</label>
</div>
<input type="submit" value="发送"/>
</form>
</body>
</html>
后台 app.py
from flask import Flask,render_template,request
app = Flask(__name__)
@app.route("/",methods=['POST','GET'])
def index():
if request.method == "POST":
data = request.values.getlist("s_option")
print("您的选择内容是: %s" %data)
return render_template("index.html")
if __name__ == '__main__':
app.run()
◆Select 选择框◆ HTML index.html
<body>
<form action="/" method="post">
<select name="MySelect">
<option selected="selected">--请选择厂家--</option>
<option >惠普</option>
<option >华为</option>
<option >戴尔</option>
</select>
<input type="submit" value="发送"/>
</form>
</body>
后台 app.py
from flask import Flask,render_template,request
app = Flask(__name__)
@app.route("/",methods=['POST','GET'])
def index():
if request.method == "POST":
data = request.values.get("MySelect")
print("您的选择内容是: %s" %data)
return render_template("index.html")
if __name__ == '__main__':
app.run()
Ajax 发送数据◆ HTML页面发送数据,后端接收并返回数据
HTML index.html
<body>
<input type="button" class="MyButton" value="发送数据">
<script src="https://code.jquery.com/jquery-3.4.1.min.js" type="text/javascript"></script>
<script type="text/javascript">
function SendAjax(){
$.ajax({
url:"/dataFromAjax",
contentType: "POST",
data:{"MyData": "hello lyshark"},
success:function(data){
alert("返回数据:" + data);
},
error:function(){
alert("执行失败了...")
}
});
}
</script>
</body>
后台 app.py
from flask import Flask,render_template,request
from flask import jsonify
app = Flask(__name__)
@app.route("/")
def index():
return render_template("index.html")
@app.route("/dataFromAjax")
def recv():
data = request.args.get("MyData")
print("收到客户端数据: %s"%data)
return "通信成功..."
if __name__ == '__main__':
app.run()
Ajax 获取数据◆ 后端发送JSON数据,HTML页面接收数据并显示出来.
HTML index.html
<body>
<input type="button" class="MyButton" value="接收数据">
<script src="https://code.jquery.com/jquery-3.4.1.min.js" type="text/javascript"></script>
<script type="text/javascript">
function GetAjax(){
$.ajax({
url:"/dataFromAjax",
contentType: "GET",
success:function(data){
alert("姓名: " + data.name + "年龄: " + data.age);
},
error:function(){
alert("执行失败了...")
}
});
}
</script>
</body>
后台 app.py
from flask import Flask,render_template,request
from flask import jsonify
app = Flask(__name__)
@app.route("/")
def index():
return render_template("index.html")
@app.route("/dataFromAjax",methods=["GET","POST"])
def set():
data = {"name":"lyshark","age":"23"}
return jsonify(data)
# info = dict() //另一种组装发送数据的方法
# info['name'] = "lyshark"
# info['age'] = 22
# return jsonify(info)
if __name__ == '__main__':
app.run()
Flask 过滤器 字符串操作:
{# 当变量未定义时，显示默认字符串，可以缩写为d #}
<p>{{ name | default('No name', true) }}</p>
{# 单词首字母大写 #}
<p>{{ 'hello' | capitalize }}</p>
{# 单词全小写 #}
<p>{{ 'XML' | lower }}</p>
{# 去除字符串前后的空白字符 #}
<p>{{ 'hello' | trim }}</p>
{# 字符串反转，返回"olleh" #}
<p>{{ 'hello' | reverse }}</p>
{# 格式化输出，返回"Number is 2" #}
<p>{{ '%s is %d' | format("Number", 2) }}</p>
{# 关闭HTML自动转义 #}
<p>{{ '<em>name</em>' | safe }}</p>
{% autoescape false %}
{# HTML转义，即使autoescape关了也转义，可以缩写为e #}
<p>{{ '<em>name</em>' | escape }}</p>
{% endautoescape %}
#用管道的形式，如果avatar（后端传过来的变量）的值不存在，则用default的值
{{ avatar|default('xxx') }}
#这里的意思为获取avatar的长度，avatar为后端传过来的变量，可以是列表，也可以是字典
{{ avatar|length }}
数值操作:
{# 四舍五入取整，返回13.0 #}
<p>{{ 12.8888 | round }}</p>
{# 向下截取到小数点后2位，返回12.88 #}
<p>{{ 12.8888 | round(2, 'floor') }}</p>
{# 绝对值，返回12 #}
<p>{{ -12 | abs }}</p>
列表操作:
{# 取第一个元素 #}
<p>{{ | first }}</p>
{# 取最后一个元素 #}
<p>{{ | last }}</p>
{# 返回列表长度，可以写为count #}
<p>{{ | length }}</p>
{# 列表求和 #}
<p>{{ | sum }}</p>
{# 列表排序，默认为升序 #}
<p>{{ | sort }}</p>
{# 合并为字符串，返回"1 | 2 | 3 | 4 | 5" #}
<p>{{ | join(' | ') }}</p>
{# 列表中所有元素都全大写。这里可以用upper,lower，但capitalize无效 #}
<p>{{ ['tom','bob','ada'] | upper }}</p>
字典列表操作:
{% set users=[{'name':'Tom','gender':'M','age':20},
{'name':'John','gender':'M','age':18},
{'name':'Mary','gender':'F','age':24},
{'name':'Bob','gender':'M','age':31},
{'name':'Lisa','gender':'F','age':19}]
%}
{# 按指定字段排序，这里设reverse为true使其按降序排 #}
<ul>
{% for user in users | sort(attribute='age', reverse=true) %}
<li>{{ user.name }}, {{ user.age }}</li>
{% endfor %}
</ul>
{# 列表分组，每组是一个子列表，组名就是分组项的值 #}
<ul>
{% for group in users|groupby('gender') %}
<li>{{ group.grouper }}<ul>
{% for user in group.list %}
<li>{{ user.name }}</li>
{% endfor %}</ul></li>
{% endfor %}
</ul>
{# 取字典中的某一项组成列表，再将其连接起来 #}
<p>{{ users | map(attribute='name') | join(', ') }}</p>
内置过滤器: tojson配合js使用,注意这里要避免HTML自动转义,所以加上safe过滤器
<script type="text/javascript">
var users = {{ users | tojson | safe }};
console.log(users.name);
</script>
自定义过滤器: 自定义过滤器其实就是一个函数,自己写即可
def mylen(arg):#实现一个可以求长度的函数
return len(arg)
# 该函数实现给定一个区间返回区间的内容
def interval(test_str, start, end):#过滤器中传递多个参数，第一个参数为被过滤的内容，第二第三个参数需要自己传入
return test_str
env = app.jinja_env
env.filters['mylen'] = mylen #注册自定义过滤器
env.filters['interval'] = interval #注册自定义过滤器
@app.route("/")
def index():
test_str = "hello"
return render_template("index.html", test_str=test_str)
#--------------------------------------------------------------------
jinja2模板
<body>
<h1>len: {{test_str|mylen}}</h1>
<h1>interval: {{test_str|interval(0,2)}}</h1> #test_str作为参数传到interval函数里
</body>
Flask 简单应用 简单的参数传递: 通过配置不同的路由路径,接受不同的参数,最后返回给用户.
from flask import Flask,render_template,request
app = Flask(__name__)
@app.route("/post/id=<id>") # 参数需要放在"<>"中,并且要与函数中传入的参数同名
def post(id): # 加入参数,函数名称要与上面的路由名称相同
return "请求的参数是 %s" %id
@app.route("/post/user=<name>&pass=<pasd>") # 可同时传递多个参数,中间的&可有可无
def user(name,pasd):
return "用户名: %s 密码: %s" %(name,pasd)
if __name__ == '__main__':
app.run(host="0.0.0.0",port="80",debug=True)
URL地址跳转 当输入正确用户名密码后,自动跳转到成功的页面上.
from flask import Flask,render_template,request
from flask import url_for,redirect
app = Flask(__name__)
@app.route("/")
def index():
return "<b> 这是首页,请先登录.. </b>"
@app.route("/post/id=<username>")
def Check(username):
if username == "admim":
return "用户%s登录完成了.." %username
else:
return redirect(url_for("login")) #失败,跳转到登陆函数（界面）
@app.route("/login/")
def login():
return "<b> 请登陆... </b>"
if __name__ == '__main__':
app.run(host="0.0.0.0",port="80",debug=True)
◆URL反向解析◆ 反转url主要用于模版和页面的重定向（从视图函数到url的转换）
from flask import Flask,render_template,request
from flask import url_for
app = Flask(__name__)
@app.route("/")
def index():
print(url_for("post",id="lyshark"))
return "/"
@app.route("/post/<id>")
def post(id):
return "<h1> hello %s </h1>" %id
if __name__ == '__main__':
app.run(host="0.0.0.0",port="80",debug=True)
◆简单的参数传递◆ HTML index.html
<body>
<p>第一个flask页面</p>
<p>姓名：{{ username }}</p>
<p>height：{{ height }}</p>
</body>
后台 app.py
from flask import Flask,url_for,redirect,render_template
app = Flask(__name__)
@app.route("/")
def index():
info = {
"username":"lyshark",
"gender":"man",
"height":"165"
}
#如果有多个参数,可以将所有的参数放到字典中,然后以**kwargs的方式传递进去,info为上面定义的字典
#这里直接写模版文件名称,如果在模版文件在temlate/html目录下,则这里需要写'html/index.html'
return render_template("index.html",**info)
#渲染模版,传参数,如果参数较少,可以直接写关键字参数及值,如下:
#return render_template('index.html',username='name',gender="man",height="178")
if __name__ == '__main__':
app.run(host="0.0.0.0",port="80",debug=True)
◆复杂的参数传递◆ HTML index.html
<body>
<p>第一个flask页面</p>
<p>姓名：{{ username }}</p>
<p>height：{{ height }}</p>
<hr>
<p>{{ person.name }}---{{ person.age }}</p> //此处对应上面py中定义的Person类
<p>{{ city.bj }}</p> //第一种取值方式
<p>{{ city['tj'] }}</p> //第二种取值方式
</body>
后台 app.py
from flask import Flask,url_for,redirect,render_template
app = Flask(__name__)
@app.route('/')
def index():
class Person(object):
name='tttt'
age=18
p = Person()
info = {
'username' :'name',
'gender':"man",
'height' : "178",
'person':p,
'city':{
'bj':"bj",
'tj':'tj'
}
}
return render_template('index.html',**info)
#return render_template('index.html',username='name',gender="man",height="178")
if __name__ == '__main__':
app.run(debug=True)
◆自定义错误页◆@app.errorhandler(404)
def page_noe_found(error):
return render_template('home/404.html'),404
@app.errorhandler(500)
def page_noe_found(error):
return render_template('home/500.html'),500
◆IF语句的使用◆ HTML: index.html
<body>
{% if users and users.age >10 %} #这里的users为py文件里传递的user字典，users.age为py文件user字典里的age
<a href="#">{{ users.aa }}</a>
<a href="#">{{users.bbb}}</a>
{% else %}
<a href="#">登陆</a>
<a href="#">注册</a>
{% endif %}
</body>
后台: app.py
from flask import Flask,url_for,redirect,render_template
app = Flask(__name__)
@app.route('/<is_login>')
def index(is_login):
if is_login == "1": #模拟1为登陆成功
user = {
"aa":"test",
'bbb':'注销',
'age':"11"
}
return render_template('index.html',users=user)
else:
return render_template('index.html')
if __name__ == '__main__':
app.run(debug=True)
◆FOR语句的使用◆ HTML: index.html
<body>
{% for k,v in user.items() %} #for语句
<p>{{ k }}----{{ v }}</p>
{% endfor %}
</body>
后台: app.py
from flask import Flask,url_for,redirect,render_template
app = Flask(__name__)
@app.route('/')
def index():
users = {
'username':'tsdf',
'age':11
}
return render_template('index.html',user=users)
if __name__ == '__main__':
app.run(debug=True)
◆钩子函数的使用◆ before_request函数,就是一个装饰器,他可以把需要设置为钩子函数的代码放到视图函数执行之前执行.
from flask import Flask,url_for,redirect,render_template,request
app = Flask(__name__)
@app.route('/')
def index():
print ('index')
return 'index'
@app.before_request
def mybefore_request():
print ('before_request')
if __name__ == '__main__':
app.run(debug=True)
Flask 常用开发片段 实现记住密码功能: 在不使用框架的情况下,手撸登录验证功能.
前端HTML页面
<script src="http://libs.baidu.com/jquery/1.9.1/jquery.min.js"></script>
<script type="text/javascript">
$(document).ready(function(){
var strName = localStorage.getItem('keyName');
var strPass = localStorage.getItem('keyPass');
if(strName){
$('#user').val(strName);
}if(strPass){
$('#pass').val(strPass);
}
if(strName!=null && strPass!=null)
$('#remember').attr("checked",true);
});
function login_click(){
var strName = $('#user').val();
var strPass = $('#pass').val();
if($('#remember').is(':checked')){
localStorage.setItem('keyName',strName);
localStorage.setItem('keyPass',strPass);
}else{
localStorage.removeItem('keyName',strName);
localStorage.removeItem('keyPass');
}
window.location.reload();
}
</script>
<body>
<form action="/" method="post">
账号: <input type="text" id="user" placeholder="用户名" name="username" /><br><br>
密码: <input type="password" id="pass" placeholder="密码" name="password" /><br><br>
记住密码: <input type="checkbox" id="remember">
<input type="submit" value="用户登录"/>
</form>
<div>
{% if flag == 1 %}
<p>当前登录用户: {{ user }} 该用户密码是: {{ pasd }}</p>
{% elif flag == 0 %}
<p>登录失败了,你输入的密码有误.</p>
{% endif %}
</div>
</body>
后台代码
from flask import Flask,render_template,request
import re
app = Flask(__name__)
@app.route("/",methods=['GET','POST'])
def index():
if request.method == "GET":
return render_template("index.html")
elif request.method == "POST":
username = request.form.get("username")
password =request.form.get("password")
if username != "" and password != "": # 用户名密码不能为空
if re.findall(r"{4,15}$", username): # 用户名不能含有特殊字符
if re.findall(r"{5,15}$", password): # 密码必须符合安全要求
if username == "admin" and password == "admin123":
print("收到用户名: %s --->收到密码: %s" % (username, password))
return render_template("index.html", flag=1,user=username, pasd=password)
else:
return render_template("index.html", flag=0)
else:
return '''<script type="text/javascript">alert('错误，密码开头必须为字母!');</script>'''
else:
return '''<script type="text/javascript">alert('错误，用户名存在特殊字符,或长度不符!');</script>'''
else:
return '''<script type="text/javascript">alert('您不能输入空的用户名或密码!');</script>'''
if __name__ == '__main__':
app.run()
◆实现用户登录功能◆ style.css
body {
display: flex;
align-items: center;
justify-content: center;
text-align: -webkit-center;
line-height: 0.5;
background: aliceblue;
}
.form-bg{
background: #00b4ef;
}
.form-horizontal{
background: #fff;
padding-bottom: 10px;
border-radius: 15px;
text-align: center;
}
.form-horizontal .heading{
display: block;
font-size: 35px;
font-weight: 700;
padding: 35px 0;
border-bottom: 1px solid #f0f0f0;
margin-bottom: 30px;
}
.form-horizontal .form-group{
padding: 0 40px;
margin: 0 0 25px 0;
position: relative;
}
.form-horizontal .form-control{
background: #f0f0f0;
border: none;
border-radius: 20px;
box-shadow: none;
padding: 0 20px 0 45px;
height: 40px;
transition: all 0.3s ease 0s;
}
.form-horizontal .form-control:focus{
background: #e0e0e0;
box-shadow: none;
outline: 0 none;
}
.form-horizontal .form-group i{
position: absolute;
top: 12px;
left: 60px;
font-size: 17px;
color: #c8c8c8;
transition : all 0.5s ease 0s;
}
.form-horizontal .form-control:focus + i{
color: #00b4ef;
}
.form-horizontal .fa-question-circle{
display: inline-block;
position: absolute;
top: 12px;
right: 60px;
font-size: 20px;
color: #808080;
transition: all 0.5s ease 0s;
}
.form-horizontal .fa-question-circle:hover{
color: #000;
}
.form-horizontal .text{
float: left;
margin-left: 7px;
line-height: 20px;
padding-top: 5px;
text-transform: capitalize;
}
.form-horizontal .btn{
font-size: 14px;
color: #fff;
border-radius: 100px;
padding: 10px 70px;
border: none;
text-transform: capitalize;
transition: all 0.5s ease 0s;
}
@media only screen and (max-width: 479px){
.form-horizontal .form-group{
padding: 0 25px;
}
.form-horizontal .form-group i{
left: 45px;
}
.form-horizontal .btn{
padding: 10px 20px;
}
}
login.html
<head>
<link rel='stylesheet' href='https://stackpath.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css'>
<link href="http://cdn.bootcss.com/font-awesome/4.6.3/css/font-awesome.min.css" rel="stylesheet">
<link rel="stylesheet" type="text/css" href="static/style.css" />
</head>
<body>
<div class="container">
<div class="row">
<div class="col-md-offset-3 col-md-6">
<form action="/login" method="post" class="form-horizontal">
<span class="heading">用 户 登 录</span>
<div class="form-group">
{{ form.username }}
<i class="fa fa-user"></i>
</div>
<div class="form-group help">
{{ form.password }}
<i class="fa fa-lock"></i>
<a href="#" class="fa fa-question-circle"></a>
</div>
<div class="form-group">
<button type="submit" class="btn btn-success">登 录 后 台</button>
</div>
</form>
</div>
</div>
</div>
</body>
flask.py
from flask import Flask, render_template, request, redirect
from wtforms import Form,validators,widgets
from wtforms.fields import simple,html5
import sqlite3
app = Flask(__name__, template_folder="templates")
class LoginForm(Form):
username = simple.StringField(
validators=[
validators.DataRequired(message=''),
validators.Length(min=4, max=15, message=''),
validators.Regexp(regex="{4,15}", message='')
],
widget=widgets.TextInput(),
render_kw={"class":"form-control",
"placeholder":"请输入用户名或电子邮件"}
)
password = simple.PasswordField(
validators=[
validators.DataRequired(message=''),
validators.Length(min=5, max=15,message=''),
validators.Regexp(regex="{5,15}",message='')
],
widget=widgets.PasswordInput(),
render_kw={"class":"form-control",
"placeholder":"请输入密码"}
)
def select(temp):
try:
conn = sqlite3.connect("D://data.db")
cursor = conn.cursor()
row = cursor.execute('select id from user where username="{}" and password="{}"'\
.format(temp['username'], temp['password']))
if len(row.fetchall()) != 0:
return 1
else:
return 0
except Exception:
return 0
@app.route("/login",methods=['GET','POST'])
def Login():
if request.method == 'GET':
RetForm = LoginForm()
return render_template('login.html', form=RetForm)
else:
RetForm = LoginForm(formdata=request.form)
if RetForm.validate():
temp = RetForm.data
ret = select(temp)
if ret != 1:
return '''<script type="text/javascript">alert('用户名或密码输入有误!');</script>'''
else:
return '''<script type="text/javascript">alert('登录完成!');</script>'''
return render_template('login.html', form=RetForm)
if __name__ == '__main__':
app.run()
◆实现用户注册功能◆ register.html
<head>
<link rel='stylesheet' href='https://stackpath.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css'>
<link href="http://cdn.bootcss.com/font-awesome/4.6.3/css/font-awesome.min.css" rel="stylesheet">
<link rel="stylesheet" type="text/css" href="static/style.css" />
</head>
<body>
<div class="container">
<div class="row">
<div class="col-md-offset-3 col-md-6">
<form action="/register" method="post" class="form-horizontal">
<span class="heading">用 户 注 册</span>
<div class="form-group">
{{ form.username }}
<i class="fa fa-user"></i>
<a href="/login" class="fa fa-question-circle"></a>
</div>
<div class="form-group">
{{ form.email }}
<i class="fa fa-envelope"></i>
</div>
<div class="form-group">
{{ form.password }}
<i class="fa fa-lock"></i>
</div>
<div class="form-group">
{{ form.RepeatPassword }}
<i class="fa fa-unlock-alt"></i>
</div>
{{ form.submit }}
</form>
</div>
</div>
</div>
</body>
app.py
from flask import Flask, render_template, request, redirect
from wtforms import Form,validators,widgets
from wtforms.fields import simple,html5
app = Flask(__name__, template_folder="templates")
class RegisterForm(Form):
username = simple.StringField(
#label='注册用户：',
validators=[
validators.DataRequired(message='用户名不能为空'),
validators.Length(min=6, max=18, message='用户名长度必须大于%(min)d且小于%(max)d')
],
widget=widgets.TextInput(),
render_kw={'class': 'form-control',
"placeholder":"输入注册用户名"}
)
email = simple.StringField(
#label='用户邮箱：',
validators=,
render_kw={'class':'form-control',
"placeholder":"输入Email邮箱"}
)
password = simple.PasswordField(
#label='用户密码：',
validators=[
validators.DataRequired(message='密码不能为空'),
validators.Length(min=5, message='用户名长度必须大于%(min)d'),
validators.Regexp(regex="{5,}",message='密码不允许使用特殊字符')
],
widget=widgets.PasswordInput(),
render_kw={'class': 'form-control',
"placeholder":"输入用户密码"}
)
RepeatPassword = simple.PasswordField(
#label='重复密码：',
validators=[
validators.DataRequired(message='密码不能为空'),
validators.Length(min=5, message='密码长度必须大于%(min)d'),
validators.Regexp(regex="{5,}",message='密码不允许使用特殊字符'),
validators.EqualTo("password",message="两次密码输入必须一致,龟孙")
],
widget=widgets.PasswordInput(),
render_kw={'class': 'form-control',
"placeholder":"再次输入密码"}
)
submit = simple.SubmitField(
label="用 户 注 册",
render_kw={ "class":"btn btn-success" }
)
@app.route('/register', methods=['GET', 'POST'])
def Register():
if request.method == 'GET':
RetForm = RegisterForm()
return render_template('register.html', form=RetForm)
else:
RetForm = RegisterForm(formdata=request.form)
if RetForm.validate():
print('接收到数据：', RetForm.data)
return '''<script>alert('您的注册请求已提交!');</script>'''
else:
print(RetForm.errors)
return render_template('register.html', form=RetForm)
if __name__ == '__main__':
app.run()
选择框使用技巧: 单选框,复选框,多选框等.
前端代码
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">
<title>页面选择</title>
</head>
<body>
<form method="post">
<p>{{ form.gender.label }} {{form.gender}} {{form.gender.errors }}</p>
<p>{{ form.city.label }} {{form.city}} {{form.city.errors }} </p>
<p>{{ form.hobby.label }} {{form.hobby}} {{form.hobby.errors }}</p>
<p>{{ form.favor.label }} {{form.favor}} {{form.favor.errors }}</p>
<input type="submit" value="提交表格">
</form>
</body>
</html>
后台代码
from flask import Flask, render_template, request, redirect
from wtforms import Form,validators,widgets
from wtforms.fields import simple,html5,core
app = Flask(__name__,template_folder="templates")
class RegisterForm(Form):
gender = core.RadioField(
label="性别：",choices=((0,"男"),(1,"女"),(0,"两面派")),coerce=int#限制是int类型的
)
city = core.SelectField(
label="选择城市：",
choices=(
("shandong","山东省"),("shanghai","上海市"),
("beijingshi","北京市"),("neimenggu","内蒙古")
),
render_kw={'class': 'btn btn-primary dropdown-toggle'}
)
hobby = core.SelectMultipleField(
label='爱好：',
choices=((1, '唱'),(2, '跳'),(3,'rap'),(4,'篮球')),
coerce=int,
render_kw = {'class': 'form-control'}
)
favor = core.SelectMultipleField(
label="特长：",
choices=((1, 'Python把妹'),(2, '渗透把妹'),(3,"运维把妹"),(4,"科学把妹")),
widget = widgets.ListWidget(prefix_label=False),
option_widget = widgets.CheckboxInput(),
coerce = int, default = ,
)
@app.route('/submit',methods=["GET","POST"])
def submit():
if request.method=="GET":
form = RegisterForm(data={'gender': 1}) # 指定性别的默认值是1
return render_template("submit.html",form=form)
else:
form = RegisterForm(formdata=request.form)
if form.validate():
print('提交的值为：', form.data)
return '''<script type="text/javascript">alert('您的请求已提交!');</script>'''
else:
print("提交数据错误..")
return render_template('submit.html', form=form)
if __name__ == '__main__':
app.run()
◆实现文件上传◆ HTML: upload.html
<script type="text/javascript">
function CheckFileType(filename)
{
var flag = false;
var arry = ["bmp","jpg"];
var index = filename.lastIndexOf(".");
var ext = filename.substr(index+1);
for(var i=0;i<arry.length;i++)
{
if(ext == arry)
{
flag=true;
break;
}
}
if(!flag){alert('错误,文件名后缀不合法!');}
}
</script>
<body>
<form action="/upload" enctype="multipart/form-data" method="post">
<input type="file" name="file">
<input type="submit" value="上传文件">
</form>
<p style="color: green">状态: {{ file_flage }}</p>
</body>
后台: app.py
from flask import Flask,render_template,request
import os,uuid
app = Flask(__name__)
app.config['MAX_CONTENT_LENGTH'] = 3000000 # 限制文件上传最大为3MB
@app.route("/upload",methods=['GET','POST'])
def upload_file():
if request.method == "GET":
return render_template("upload.html")
elif request.method == "POST":
file = request.files["file"]
filename = str(file.filename)
if len(filename) >= 20: # 限制文件名的长度必须在20个字符以内
return render_template("upload.html",file_flage="文件名长度超出了限制!")
else:
if filename.find(".") >= 0:# 查找文件中是否包含点这个字符
filetype = file.filename.split(".") # 取出文件类型,后期做判断
if filetype != None and filetype == "bmp": # 后缀格式必须是bmp结尾
uid = uuid.uuid4() # 生成随机名称
save_file_name = str(uid) + "." + filetype# 拼接名称
file.save(save_file_name) # 保存文件
return render_template("upload.html",file_flage="文件上传成功 {}".format(save_file_name))
else:
return render_template("upload.html",file_flage="没有选择文件,或不是图片格式,上传失败!")
return render_template("upload.html",file_flage="文件上传失败,未知错误!")
if __name__ == '__main__':
app.run()
实现文件下载<script type="text/javascript">
function Download(filename)
{
if(filename){window.location.href='/download/?path=' + filename}
}
</script>
<body>
<form action="/download" enctype="multipart/form-data" method="get">
<input type="text" name="down"/>
<input type="submit" value="下载文件" >
</form>
</body>
from flask import Flask, render_template, request, Response
app = Flask(__name__)
@app.route('/download/', methods=['GET', 'POST'])
def download_file():
if request.method == 'GET':
args = request.args.get("path").replace("/","").replace("\\","")
args = args.replace("<>","").replace("<!--","")
args = "./templates/" + args
print("下载的文件: {}".format(args))
def send_file():
store_path = args
with open(store_path, 'rb') as targetfile:
while 1:
data = targetfile.read(10 * 1024 * 1024) # 每次读取10M
if not data:
break
yield data
response = Response(send_file(), content_type='application/octet-stream')
response.headers["Content-disposition"] = 'attachment; filename=%s'%args.split("/")# 取出下载的名字
return response
if __name__ == '__main__':
app.run()
实现前端组合数据,后端接受
<body>
<script src="https://code.jquery.com/jquery-3.4.1.min.js" type="text/javascript"></script>
<script type="text/javascript">
function SendAjax(){
var username = $('input').val();
var password = $('input').val();
var json = {"username":username,"password":password};
$.ajax({
url:"/dataFromAjax",
contentType: "POST",
data:json,
success:function(data){
if(data=="1"){alert("请求已经提交.");}
},
error:function(){
//alert("执行失败了...")
}
});
}
</script>
<form action="/dataFromAjax" method="post">
用户账号: <input type="text" placeholder="用户账号" name="username" /><br><br>
用户密码: <input type="text" placeholder="用户密码" name="password" /><br><br>
<input type="button" value="发送数据">
</form>
</body>
from flask import Flask,render_template,request
from flask import jsonify
app = Flask(__name__)
@app.route("/")
def index():
return render_template("index.html")
@app.route("/dataFromAjax",methods=['GET'])
def recv():
username = request.args.get("username")
password = request.args.get("password")
if(username=="" or password ==""):
return "0"
else:
print("收到客户{} 密码 {} ".format(username,password))
return "1"
if __name__ == '__main__':
app.run()
◆实现Session◆from flask import Flask,render_template,request
from flask import session,url_for,escape,redirect
import os
app = Flask(__name__)
@app.route('/')
def index(): #自动验证session
if 'username' in session:
return '用户 %s 已经登陆成功...' % escape(session['username'])
return '您还没有登陆呢...'
@app.route('/login', methods=['GET', 'POST'])
def login(): #登陆session
if request.method == 'POST':
session['username'] = request.form['username']
return redirect(url_for('index'))
return '''
<form action="" method="post">
<p><input type=text name=username>
<p><input type=submit value=登陆>
</form>
'''
@app.route('/get')
def get(): #获取session
return "用户: %s" %session.get('username')
@app.route('/logout')
def logout(): #注销session
session.pop('username', None)
# session.clear() #清空session里的所有数据
return redirect(url_for('index'))
app.secret_key = os.urandom(24) #加盐,服务端每次重启都会变化
if __name__ == '__main__':
app.run()
◆表格结构遍历◆ HTML index.html
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">
<body>
<form action="/" method="post">
<input type="text" placeholder="姓名" name="username" />
<input type="text" placeholder="性别" name="usersex" />
<input type="text" placeholder="邮箱" name="email" />
<input type="text" placeholder="手机号" name="phone" />
<input type="text" placeholder="留言内容" name="usertext" />
<input type="submit" value="点我提交表单"/>
</form>
<br>
<table border="1" class="table table-hover">
<thead>
<th>用户IP</th> <th>用户姓名</th> <th>性别</th> <th>邮箱</th> <th>手机号</th><th>留言</th>
</thead>
<tbody>
{% for temp in user %}
<tr>
<td>{{ temp.userip }}</td>
<td>{{ temp.username }}</td>
<td>{{ temp.usersex }}</td>
<td>{{ temp.email }}</td>
<td>{{ temp.phone }}</td>
<td>{{ temp.usertext }}</td>
</tr>
{% endfor %}
</tbody>
</table>
</body>
后台: app.py
from flask import Flask,render_template,request
import json
app = Flask(__name__)
temp = [ ]
@app.route("/",methods=['GET','POST'])
def index():
if request.method == "GET":
return render_template("index.html", user=temp)
elif request.method == "POST":
userip = str(request.remote_addr)
username = request.form.get("username")
usersex = request.form.get("usersex")
email = request.form.get("email")
phone = request.form.get("phone")
usertext = request.form.get("usertext")
if username != "" and usertext != "" and usersex != "" and email != "":
data = {"userip":userip,"username":username,"usersex":usersex,"email":email,"phone":phone,"usertext":usertext}
temp.append(data) #追加数据到列表
with open("data.json", "w", encoding="UTF-8") as f:
s = json.dump(temp, f, ensure_ascii=False)
return render_template("index.html",user=temp)
returnrender_template("index.html",user=temp)
if __name__ == '__main__':
app.run()
模态对话框的使用: 后台接收参数,与上方相同,区别在于使用BootCSS弹框.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>弹出式编辑框</title>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">
<script src="https://code.jquery.com/jquery-3.4.1.slim.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"></script>
</head>
<body>
<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#exampleModal" data-whatever="@mdo">编辑主机</button>
<div class="modal fade" id="exampleModal" tabindex="-1" role="dialog" aria-labelledby="exampleModalLabel" aria-hidden="true">
<div class="modal-dialog" role="document">
<div class="modal-content">
<div class="modal-header">
<h5 class="modal-title" id="exampleModalLabel">编辑运维主机</h5>
<button type="button" class="close" data-dismiss="modal" aria-label="Close">
<span aria-hidden="true">X</span>
</button>
</div>
<!--主体框架,使用form表单提交-->
<div class="modal-body" >
<form action="/edit" method="post">
<!--按钮主体框架-->
<div class="form-group">
<label class="form-inline" for="recipient-name" class="col-form-label">主机名称：</label>
<input type="text" class="form-control" id="recipient-name" name="hostname">
</div>
<div class="form-group">
<label class="form-inline" for="recipient-name" class="col-form-label">IP地址:</label>
<input type="text" class="form-control" id="recipient-name" name="ipaddress">
</div>
<!--关闭事件,此处只有两个按钮-->
<div style="display: block;text-align: center;" class="modal-footer">
<button type="button" class="btn btn-secondary" data-dismiss="modal">关闭窗口</button>
<button type="submit" class="btn btn-primary">提交数据</button>
</div>
</form>
</div>
</div>
</div>
</div>
</body>
</html>
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