http
协议即:Hyper Text Transfer Protocol
(超文本传输协议),于1990年提出,是用于万维网(World Wide Web)
服务器与本地浏览器之间传输超文本的传送协议
TCP/IP
协议之上的应用层协议
M
代表模型(Model):负责业务对象与数据库的映射
V
代表视图(View):负责与用户交互(页面)
C
代表控制器(Controller):接收用户的输入,调用模型和视图完成用户的请求
M
代表模型(Model):负责业务对象和数据库的关系映射(ORM)T
代表模板(Template):负责如何将页面展示给用户(html)
V
代表视图(View):负责业务逻辑,并在适当时候调用Mode
l和Template
一般是用户通过浏览器向服务器发送一个请求(request),首先会去访问视图函数,如果不涉及数据的调用(那么这个时候视图函数返回一个模板,也就是你一个网页给用户),视图函数调用模型,模型去数据库查找数据,然后逐级返回,视图函数把返回的数据填充到模板的空格中,最后返回网页给用户
cmd
命令行:pip3 install django
,或可以指定版本号下载:pip3 install django==1.11.9
pycharm
进行安装
django project
django-admin startproject 项目名 # windows命令
python manage.py startapp app名 # Windows命令
django
项目
python manage.py runserver 8000
python manage.py runserver 127.0.0.1:8000
127.0.0.1:8000
就OK了
STATIC_URL = '/static/'
# 创建一个static文件夹
STATICFILES_DIRS = [
# 将static文件夹拼接到根目录下
os.path.join(BASE_DIR, 'static'),
]
方法一:用static标签函数
{% load static %}
<img src="{% static "images/aa.jpg" %}"/>
或者上面也可这样写
{% load static %}
{% static "images/aa.jpg" as photo %}
<img src="{{ photo }}"/>
方法二:用get_static_prefix标签,它返回的就是/static/
{% load static %}
<img src="{% get_static_prefix %}images/aa.jpg"/>
同样也可以定以为一个易用的变量
{% load static %}
{% get_static_prefix as photo %}
<img src="{{ photo }}images/aa.jpg" />
TEMPLATES = [
{
'BACKEND': 'django.template.backends.django.DjangoTemplates',
'DIRS': [os.path.join(BASE_DIR, 'templates')]
,
'APP_DIRS': True,
'OPTIONS': {
'context_processors': [
'django.template.context_processors.debug',
'django.template.context_processors.request',
'django.contrib.auth.context_processors.auth',
'django.contrib.messages.context_processors.messages',
],
},
},
]
LOGGING = {
'version': 1,
'disable_existing_loggers': False,
'handlers': {
'console': {
'level': 'DEBUG',
'class': 'logging.StreamHandler',
},
},
'loggers': {
'django.db.backends': {
'handlers': ['console'],
'propagate': True,
'level': 'DEBUG',
},
}
}
<!DOCTYPE html>
<html lang="zh">
<head>
<meta charset="UTF-8">
<link rel="stylesheet" href="../static/bootstrap-3.3.7/css/bootstrap.css">
<link rel="stylesheet" href="../static/css/style.css">
<title>login</title>
</head>
<body>
<h1>登录</h1>
<div class="col-md-6 col-md-offset-3">
<form action="/login/" method="post">
<p>user:<input type="text" name="name" class="form-control"></p>
<p>password:<input type="password" name="pwd" class="form-control"></p>
<input type="submit" value="提交">
</form>
</div>
</body>
</html>
templates----login.html
from django.shortcuts import render, HttpResponse
import pymysql
from login import models
# Create your views here.
def login(request):
# print('login')
if request.method == 'GET':
return render(request, 'login.html')
elif request.method == 'POST':
print(request.POST)
# 从POST拿到name和pwd
name = request.POST.get('name')
pwd = request.POST.get('pwd')
# 一、用 pymysql 连接数据库
conn = pymysql.connect(host='127.0.0.1', port=3306, db='user_info', user='root', password='95500')
cur = conn.cursor()
cur.execute('select * from user where name = %s and passwoed = %s', [name, pwd])
user = cur.fetchone()
# 二、通过 orm 用 pycharm 连接数据库
# user = models.User.objects.filter(name=name,pwd=pwd).first()
if user:
return HttpResponse('successful')
else:
return HttpResponse('wrong')
login(app名)----views.py
# 为了避免程序报错,在settings里找到MIDDLEWARE将中间的第四行注释掉
MIDDLEWARE = [
'django.middleware.security.SecurityMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.common.CommonMiddleware',
# 'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware',
]
import pymysql
conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', db='test', password=95500)
# connect --> __init__.py(Connect) --> connections.py(Connection的__init__方法)
'''
def __init__(self, host=None, user=None, password="",
database=None, port=0, unix_socket=None,
charset='', sql_mode=None,
read_default_file=None, conv=None, use_unicode=None,
client_flag=0, cursorclass=Cursor, init_command=None,
connect_timeout=10, ssl=None, read_default_group=None,
compress=None, named_pipe=None,
autocommit=False, db=None, passwd=None, local_infile=False,
max_allowed_packet=16*1024*1024, defer_connect=False,
auth_plugin_map=None, read_timeout=None, write_timeout=None,
bind_address=None, binary_prefix=False, program_name=None,
server_public_key=None):
'''
# pymysql.cursors.DictCursor 拿到的是字典类型
cour = conn.cursor(pymysql.cursors.DictCursor)
# 要查询的SQL语句
cour.execute('select * from user')
dic = cour.fetchall()
# dic = cour.fetchone()
print(dic)
orm:即
对象关系映射(object relational mapping
)
orm
的使用:
settings
里对DATABASES
进行配置
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.mysql',
'HOST': '127.0.0.1',
'PORT': 3306,
'USER': 'root',
'PASSWORD': '95500',
'NAME': 'user_info', # 需要自己手动创建数据库
}
}
注意:Django的orm不会自动创建数据库,但可以创建数据表和字段
app
目录下的__init__.py
里写上:
import pymysql
# 替换为pymysql
pymysql.install_as_MySQLdb()
from django.db import models
# Create your models here.
# 创建字段
class User(models.Model):
# 自增int类型
id = models.AutoField(primary_key=True)
# name,pwd 是一个 varcher 类型,长度为32
name = models.CharField(max_length=32)
pwd = models.CharField(max_length=32)
cmd
中输入以下命令
python3 manage.py makemigrations ---- # 会在migrations文件夹下自动生成0001_initial.py目录,记录数据库的变化
python3 manage.py migrate ---- # 将变化同步到数据库中
其中带有 app名_类名 的就是我们所创建的表,eg:login_user
name = models.CharField(max_length=32, [default=''])
# 需要注意的是,后来添加的字段需要手动添加默认值
# 方法1. models.py中创建字段时直接在后面添加一个默认值,default='值'
# 方法2. 在输入数据迁移的第一个命令时,选择1,然后键入一个str类型的值
id = models.AutoField(primary_key=True)
# 删除时可直接删除掉该字段,或注释,如:
# name = models.CharField(max_length=32)
name = models.CharField(max_length=32)
# 直接修改需要的字段即可,如:
names = models.CharField(max_length=64)
from django.shortcuts import render, redirect
from firstapp.models import *
# Create your views here.
def check(request):
if request.method == 'GET':
info = Info.objects.all()
return render(request, 'check.html', {'user_info': info})
def delete_info(request):
if request.method == 'GET':
id = request.GET.get('id')
Info.objects.filter(id=id).delete()
return redirect('/check/')
def update_info(request):
if request.method == 'GET':
id = request.GET.get('id')
res = Info.objects.filter(id=id).first()
return render(request, 'update_info.html', {'user': res})
if request.method == 'POST':
id = request.GET.get('id')
name = request.POST.get('name')
password = request.POST.get('password')
address = request.POST.get('address')
Info.objects.filter(id=id).update(name=name, password=password, address=address)
return redirect('/check/')
def add_info(request):
if request.method == 'GET':
return render(request, 'add_info.html')
if request.method == 'POST':
name = request.POST.get('name')
password = request.POST.get('password')
address = request.POST.get('address')
Info.objects.create(name=name, password=password, address=address)
return redirect('/check/')
user(项目名)\firstapp(app名)\views.py
from django.db import models
# Create your models here.
class Info(models.Model):
id = models.AutoField(primary_key=True)
name = models.CharField(max_length=64)
password = models.CharField(max_length=64)
address = models.CharField(max_length=64)
user\firstapp\models.py
import pymysql
pymysql.install_as_MySQLdb()
user\firstapp\__init__.py
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>add_info</title>
</head>
<body>
<form action="" method="post">
<p>name:<input type="text" name="name"></p>
<p>passwd:<input type="password" name="password"></p>
<p>address:<input type="text" name="address"></p>
<p><input type="submit" value="提交"></p>
</form>
</body>
</html>
user\templates\add_info.html
<!DOCTYPE html>
<html lang="zh">
<head>
<meta charset="UTF-8">
<title>check</title>
<link rel="stylesheet" href="../static/bootstrap-3.3.7/css/bootstrap.css">
</head>
<body>
<table border="2" class="col-md-4 col-md-offset-4">
<thead>
<tr>
<th>id</th>
<th>name</th>
<th>password</th>
<th>address</th>
<th>操作</th>
<th>编辑</th>
</tr>
</thead>
<tbody>
{% for user in user_info %}
<tr>
<td>{{ user.id }}</td>
<td>{{ user.name }}</td>
<td>{{ user.password }}</td>
<td>{{ user.address }}</td>
<td><a href="/delete_info/?id={{ user.id }}">delete</a></td>
<td><a href="/update_info/?id={{ user.id }}">update</a></td>
</tr>
{% endfor %}
</tbody>
</table>
<button><a href="/add_info/">add</a></button>
</body>
</html>
user\templates\check.html
<!DOCTYPE html>
<html lang="zh">
<head>
<meta charset="UTF-8">
<title>update</title>
</head>
<body>
<form action="/update_info/?id={{ user.id }}" method="post">
<p>name:<input type="text" name="name" value="{{ user.name }}"></p>
<p>passwd:<input type="text" name="password" value="{{ user.password }}"></p>
<p>address:<input type="text" name="address" value="{{ user.address }}"></p>
<p><input type="submit" value="提交"></p>
</form>
</body>
</html>
user\templates\update_info.html
"""
Django settings for user project.
Generated by 'django-admin startproject' using Django 1.11.9.
For more information on this file, see
https://docs.djangoproject.com/en/1.11/topics/settings/
For the full list of settings and their values, see
https://docs.djangoproject.com/en/1.11/ref/settings/
"""
import os
# Build paths inside the project like this: os.path.join(BASE_DIR, ...)
BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
# Quick-start development settings - unsuitable for production
# See https://docs.djangoproject.com/en/1.11/howto/deployment/checklist/
# SECURITY WARNING: keep the secret key used in production secret!
SECRET_KEY = 'm&6g#c(w#9cbv*sh04**-cda^(=*oc51k9%0xm#gkay)1a2hz)'
# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = True
ALLOWED_HOSTS = []
# Application definition
INSTALLED_APPS = [
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
'firstapp.apps.FirstappConfig',
]
MIDDLEWARE = [
'django.middleware.security.SecurityMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.common.CommonMiddleware',
# 'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware',
]
ROOT_URLCONF = 'user.urls'
TEMPLATES = [
{
'BACKEND': 'django.template.backends.django.DjangoTemplates',
'DIRS': [os.path.join(BASE_DIR, 'templates')]
,
'APP_DIRS': True,
'OPTIONS': {
'context_processors': [
'django.template.context_processors.debug',
'django.template.context_processors.request',
'django.contrib.auth.context_processors.auth',
'django.contrib.messages.context_processors.messages',
],
},
},
]
WSGI_APPLICATION = 'user.wsgi.application'
# Database
# https://docs.djangoproject.com/en/1.11/ref/settings/#databases
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.mysql',
'HOST': '127.0.0.1',
'PORT': 3306,
'USER': 'root',
'PASSWORD': '95500',
'NAME': 'info_of_user',
}
}
# Password validation
# https://docs.djangoproject.com/en/1.11/ref/settings/#auth-password-validators
AUTH_PASSWORD_VALIDATORS = [
{
'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
},
{
'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
},
{
'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
},
{
'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
},
]
# Internationalization
# https://docs.djangoproject.com/en/1.11/topics/i18n/
LANGUAGE_CODE = 'en-us'
TIME_ZONE = 'UTC'
USE_I18N = True
USE_L10N = True
USE_TZ = True
# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/1.11/howto/static-files/
STATIC_URL = '/static/'
STATICFILES_DIRS = [
os.path.join(BASE_DIR, 'static')
]
user\user\settings.py
"""user URL Configuration
The `urlpatterns` list routes URLs to views. For more information please see:
https://docs.djangoproject.com/en/1.11/topics/http/urls/
Examples:
Function views
1. Add an import: from my_app import views
2. Add a URL to urlpatterns: url(r'^$', views.home, name='home')
Class-based views
1. Add an import: from other_app.views import Home
2. Add a URL to urlpatterns: url(r'^$', Home.as_view(), name='home')
Including another URLconf
1. Import the include() function: from django.conf.urls import url, include
2. Add a URL to urlpatterns: url(r'^blog/', include('blog.urls'))
"""
from django.conf.urls import url
from django.contrib import admin
from firstapp import views
urlpatterns = [
url(r'^admin/', admin.site.urls),
url(r'^check/', views.check),
url(r'^delete_info/', views.delete_info),
url(r'^update_info/', views.update_info),
url(r'^add_info/', views.add_info),
]
user\user\urls.py
# 1 单表查询所有用户:
models.User.objects.all()
# 得到的是 queryset对象(当成列表),列表里面,一个一个的对象[user1,user2]
# 2. render的三个参数
render(request, 'userlist.html', {'user_list': ret})
# 3 for循环模板:
{%for user in user_list %}
# 要循环的内容
{{user.name}}
{% endfor %}
# 4 get请求携带参数:
http://127.0.0.1:8000/deleteuser/?id = 1
# 后台取值方法:
request.GET.get('id') # 推荐使用该方法
request.GET['id']
# 5 orm删除记录
models.User.objects.filter(id=id).delete()
# 返回值:影响的行数
# 6 前台post提交的数据取值:
name = request.POST.get('name')
# 7 orm保存的两种方式:
#方法1
user = models.User.objects.create(name=name, password=pwd, address=addr)
#方法2
user = models.User(name=name, password=pwd, address=addr)
user.save()
# 8 orm查询单条数据:
user = models.User.objects.filter(id=id).first() # 取出的是第一条数据
# 9 orm的修改
models.User.objects.filter(id=id).update(name=name, password=pwd, address=addr)
其本质就是URL与要为该URL调用的视图函数之间的映射关系
from django.conf.urls import url
from django.contrib import admin
from author import views
urlpatterns = [
url(r'^admin/', admin.site.urls),
url(r'^author/$', views.author),
]
# 其中 ^author/$ 这个路由对应的就是 views.author 这个函数的内存地址,在浏览器输入该路由,就会响应到这个函数,而通过Django内部就可以调用该函数执行其逻辑代码
'''
url(正则表达式, views视图函数, 参数, 别名)
参数:可选,字典形式
别名:可选,name=''
'''
from django.urls import path,re_path
from app01 import views
urlpatterns = [
re_path(r'^articles/2003/$', views.special_case_2003),
re_path(r'^articles/([0-9]{4})/$', views.year_archive),
re_path(r'^articles/([0-9]{4})/([0-9]{2})/$', views.month_archive),
re_path(r'^articles/([0-9]{4})/([0-9]{2})/([0-9]+)/$', views.article_detail),
]
(?P<name>pattern)
# 其中name为组的名称,pattern为匹配的模式
from django.conf.urls import url
from app01 import views
urlpatterns = [
url(r'^articles/2003/$', views.special_case_2003),
url(r'^articles/(?P<year>[0-9]{4})/$', views.year_archive),
url(r'^articles/(?P<year>[0-9]{4})/(?P<month>[0-9]{2})/$', views.month_archive),
url(r'^articles/(?P<year>[0-9]{4})/(?P<month>[0-9]{2})/(?P<day>[0-9]{2})/$', views.article_detail),
]
#捕获到的数据都是str类型
#视图函数里可以指定默认值
url('blog/$', views.blog),
url('blog/?(?P<num>[0-9]{1})', views.blog),
def blog(request,num=1):
print(num)
return HttpResponse('ok')
# 总路由的配置
from django.conf.urls import include
url(r'^book/',include('book.urls'))
url(r'^author/',include('author.urls'))
# 注意点:正则后面不能加$符号,不然匹配不到分发之后的路由
# 在book的app的urls里配置路由关系
from django.conf.urls import url
from book import views
urlpatterns = [
url(r'^book/$', views.book),
url(r'^delete/$', views.delete_book),
url(r'^add/$', views.add_book),
]
# 在author的app的urls里配置路由关系
from django.conf.urls import url
from author import views
urlpatterns = [
url(r'^author/$', views.author),
url(r'^delete/$', views.delete_author),
url(r'^update/$', views.update_author),
url(r'^add/$', views.add_author),
]
View Code
# 无参数:
url('r^book/$', views.add_book, name='add')
# 带参数时:
# 无名分组
url(r'^book/([0-9]{4})/([0-9]{2})/$', views.add_book,name='add')
# 有名分组
url(r'^book/(?P<year>[0-9]{4})/(?P<mounth>[0-9]{2})/$', views.add_book,name='add')
# 无参数
{% url 'add' %}
# 带参数:
# 无名分组:
{% url 'add' 2018 11 %}
# 有名分组:
{% url 'add' 2018 11 %} # 位置参数
# 有名分组:
{% url 'add' year=2018 month=11 %} # 关键字参数
from django.shortcuts import reverse
# 在视图层的函数中
# 无参数时:
url = reverse('add')
# 带参数时:
# 无名分组:
url = reverse('add',args=(2018,11,))
# 有名分组(位置参数):
url = reverse('add',args=(2018,11,))
# 有名分组(关键字参数):
url = reverse('add',kwargs={'year':2018, 'month':11})
# 路由
url(r'^book/(?P<id>\d+.html)',views.book)
# 访问
http://127.0.0.1:8000/book/1.html
re_path:跟1.X 的url用法相同(url,re_path分组分出来的数据,是字符串)
eg:path('test/<path:year>', views.re_test),
str, # 匹配除了路径分隔符(/)之外的非空字符串,这是默认的形式
int, # 匹配正整数,包含0。
slug, # 匹配字母、数字以及横杠、下划线组成的字符串。
uuid, # 匹配格式化的uuid,如 075194d3-6885-417e-a8a8-6c931e272f00。
path, # 匹配任何非空字符串,包含了路径分隔符(/)(不能用?)
自定义转换器
# 1、定义一个类
class MyCon:
# 写一个正则表达式
regex = '[0-9]{4}'
# 匹配出來的数据,会传到这里,retrun回去的,会被视图函数接收
def to_python(self, value):
return int(value)
# 反向解析用的
def to_url(self, value):
return '%04d' % value
# 2、导入模块
from django.urls import register_converter
register_converter(MyCon,'yyy')
# 3、使用
path('test/<yyy:year>', views.re_test,name='test')
补充:settings设置
APPEND_SLASH=False
# 为假,不会加反斜杠
补充:return render(request, 'index.html', {'name': user})
可以将第三个参数(字典)写做locals(),它能将当前视图函数的所有变量传到模板中
return render(request, 'index.html', locals())
request.POST # 前台Post传过来的数据,包装到POST字典中
request.GET # 前台浏览器窗口里携带的数据,包装到GET字典中
request.method # 前台请求的方式
request.body # post提交的数据,body体的内容,前台会封装成:name=lqz&age=18&sex=1
print(request.path) # 取出请求的路径,取不到数据部分
print(request.get_full_path()) # 取出请求的路径,能取到数据部分
print(request.META)
# 三件套:
render,HttpResponse,redirect
# render函数:
temp=Template('<h1>{{ user }}</h1>')
con=Context({'user':'lqz'})
ret=temp.render(con)
print(ret)
# return render(request,'index.html')
return HttpResponse(ret)
# -导入:
from django.http import JsonResponse
# -视图函数中:
def test(request):
import json
dic={'name':'lqz','age':18}
ll = ['name', 'age']
# 把字典转换成json格式,返回到前台
return HttpResponse(json.dumps(dic))
# 把列表转换成json格式,返回到前台
return HttpResponse(json.dumps(ll))
# 把字典转换成json格式,返回到前台
return JsonResponse(dic)
# 报错,默认不支持列表形式
return JsonResponse(ll)
# 支持列表形式
return JsonResponse(ll,safe=False)
# -1 路由层
url(r'^test/', views.Test.as_view())
# -2 视图层
from django.views import View
# -写一个类:
class Test(View):
def get(self, request): #一定要传request对象
return HttpResponse('get-test')
def post(self, request):
return HttpResponse('post-test')
变量:{{ 变量名 }}
深度查询,用句点符号
过滤器
标签:{% %}
注意点:{{变量名}} 相当于print了该变量
{{args1|过滤器名字:args2}}
# length 统计长度
# default 默认值
{{ l1|default:'12345' }} # l1为空列表,默认值为12345
{{ 'abcd'|default:'12345' }} # abcd
# slice 切分,可指定步长
{{'abcdefg'|slice:'0:3:2'}} # aceg
# date 使用date可以指定时间的格式,如:
#views.py中
import datetime
ctim=datetime.datetime.now()
# index.html中
{{ ctim }} # Nov. 11, 2018, 10:30 a.m.
{{ ctim|date:'Y-m-d' }} # 2018-11-11
{{ ctim|date }} # Nov. 11, 2018
# filessizeformat 可以将文件大小转换成KB、MB、GB、TB、PB等,方便计算
# truncatechars 一个参数,最少3位字符,剩余用...代替
{{ 'dafddfafgadfgaasdgadgfadaf'|truncatechars:5 }} # da...
# truncatewords 一个参数,指定长度,取出的是单词的个数
{{ '我 dfaf ga dfgaas 你 dgf adaf'|truncatewords:3 }} # 我 dfaf ga...
# safe 使用safe会将HTML标签解析,不使用则不会解析HTML标签
# add 字符串拼接,加法运算
# views.py
info = [
{'name': 'jack', 'age': 18},
{'name': 'bob', 'age': 19},
{'name': 'peter', 'age': 20},
{'name': 'zero', 'age': 23}
]
遍历每个元素
<table border="1">
{% for foo in info %}
<tr>
<td>{{ foo.name }}</td>
<td>{{ foo.age }}</td>
</tr>
{% endfor %}
</table>
当需要循环显示序号时,可以通过{{forloop}}
forloop.counter The current iteration of the loop (1-indexed) 当前循环的索引值(从1开始)
forloop.counter0 The current iteration of the loop (0-indexed) 当前循环的索引值(从0开始)
forloop.revcounter The number of iterations from the end of the loop (1-indexed) 当前循环的倒序索引值(从1开始)
forloop.revcounter0 The number of iterations from the end of the loop (0-indexed) 当前循环的倒序索引值(从0开始)
forloop.first True if this is the first time through the loop 当前循环是不是第一次循环(布尔值)
forloop.last True if this is the last time through the loop 当前循环是不是最后一次循环(布尔值)
forloop.parentloop 本层循环的外层循环
for 标签带有一个可选的{% empty %} 从句,以便在给出的组是空的或者没有被找到时,可以有所操作,执行empty之后的语句
{# 循环的对象是空,才会走到empty,而不是对象里面的东西为空 #}
{% for foo in dic %} {# dic为空字典 #}
<p>{{ foo }}</p>
{% empty %}
傻逼了
{% endfor %}
{# 傻逼了 #}
{% if %}会对一个变量求值,如果它的值是“True”(存在、不为空、且不是boolean类型的false值),对应的内容块会输出,False时则不会输出
{# num=56 #}
{% if num > 100 or num < 0 %}
<p>错误</p>
{% elif num > 80 and num < 100 %}
<p>牛逼</p>
{% elif num > 60 %}
<p>不错哦</p>
{% else %}
<p>垃圾</p>
{% endif %}
{# 垃圾 #}
if语句同样支持 and 、or、==、>、<、!=、<=、>=、in、not in、is、is not等逻辑运算判断。
可以为变量起别名
{% with total=business.employees.count %}
{{ total }} employee{{ total|pluralize }}
{% endwith %}
{# 或者可写成 with...as... #}
{% with business.employees.count as total %}
{{ total }} employee{{ total|pluralize }}
{% endwith %}
{% csrf_token %}
该标签用于跨站请求伪造保护
# 第一步,导入template
from django.template import Library
# 第二步,定义一个叫register的变量=Library()
register = Library()
# 第三步
# 自定义过滤器
@register.filter(name='ad') # name可以为定义的函数起别名,.filter是规定写法
def str_add(str1, str2):
# 业务逻辑很复杂
return str1 + str2
# 自定义标签
@register.simple_tag()
def add_nb(args1, ...):
return args1 + 'nb'
{% load mytag %}
{#传多个参数的话可以:'aaa:bb:cc'然后切分开,也可以传列表#}
<p>{{ 'jack'|ad:'nb' }}</p>
{# jacknb #}
<p>{% add_nb 'peter' %}</p>
{# peternb #}
注意点:
过滤器,可以用在if判断中使用
{% if 'lqz'|ad:'nb' %}
<p>肯定是True</p>
{% endif %}
标签不能用在if判断(会报错)
{#{% if add_nb 'egon' %}#}
{# #}
{#{% endif %}#}
运行结果如下:
{% include 模板名 %} 如:{% include 'index.html' %}
// 写在 {% block 模板名 %}和{% endblock %}之间的才能够被继承
如:base.html(这是个母板)
{% block sidebar %}
<ul>
<li><a href="/">Home</a></li>
<li><a href="/blog/">Blog</a></li>
</ul>
{% endblock %}
// 继承上面的母板
{% extends "base.html" %}
// 重用母板的内容
{{ block.super }}
如:
{% block sidebar %}
{{ block.super }}
{% endblock %}