django_基础

常用命令

python manage.py runserver 0.0.0.0
python manage.py startapp appname
python manage.py syncdb
python manage.py makemigrations
python manage.py migrate
    
python manage.py createsuperuser

django-admin startproject mysite

配置文件

配置模板文件

TEMPLATE_DIRS = (
        os.path.join(BASE_DIR,'templates'),
    )

配置静态文件

STATICFILES_DIRS = (
        os.path.join(BASE_DIR,'static'),
    )

路由系统

基于正则的路由
注意：两种正则的路由，只能同时使用一种，不能混用

# 路由系统
urlpatterns = [
url(r'^index1/(\d+)/(\d+)', index1),
url(r'^index1/(?P<n1>\d+)/(?P<n2>\d+)', index2),
]

# views函数
def index1(request,a1,a2):
    print("----",a1,"-----",a2,"-------")
    return HttpResponse("from index1")

# 注意：
def index2(request,n1,n2):
    print("----",n1,"=====",n2,"-------")
    return HttpResponse("from index1")

路由分发

# 主站
from django.conf.urls import include
urlpatterns = [
    url(r'^app01/', include("app01.urls")),
    url(r'^app02/', include("app02.urls")),
]

# 分发路由
from django.conf.urls import url
from app01 import views
urlpatterns = [
    url(r'^index.html$', views.index),
]
 
# 127.0.0.1:8080/app01/index.html

路由设置别名

Model中使用获取URL  自定义get_absolute_url() 方法
模板中使用生成URL   {% url 'h2' 2012 %}
用于反生成url

# project/urls.py
from django.urls import reverse

# reverse根据别名，反生成URL
# views函数
def index(request,a1):
    user_list=["zou","run","cheng"]
    v = reverse("n1",args=(123456,))
    print(v)  # /index/123456 
    return HttpResponse("...")

# 路由系统
urlpatterns = [
    url(r'^index/(\d+)', index,name="n1"),
]

配置数据库

1.在Mysql中创建数据库

2.在settings中配置DATABASE

    DATABASES = {
    	'default': {
    		'ENGINE': 'django.db.backends.mysql',
    		'NAME':'s4day70db',
    		'USER': 'root',
    		'PASSWORD': '',
    		'HOST': 'localhost',
    		'PORT': 3306,
    		}
    }

3.在与project同名的init下修改django中默认连接数据库的方式

    import pymysql
    pymysql.install_as_MySQLdb()

4.在settings.py中注册app01

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'app01',
]

5.运行命令创建数据表

python manage.py makemigrations
python manage.py migrate

ORM增删改查

from django.shortcuts import render,HttpResponse
from app01 import models
def index(request):
    # 增
    models.UserGroup.objects.create(title="研发部")
    models.UserInfo.objects.create(username="alex",password="123",age=18,ug_id=1)

    # 查
    # filter(id=1)的结果是[obj，]
    # filter(id=1).first()的结果是obj
    group_list = models.UserGroup.objects.all()
    group_list = models.UserGroup.objects.filter(id__gt=2)
    group_list = models.UserGroup.objects.filter(id=4).first()
    for row in group_list:
        print(row.id,row.title)

    # 删
    models.UserGroup.objects.filter(id=7).delete()
    # 改
    models.UserGroup.objects.filter(id=6).update(title="外交部")
    return HttpResponse("hello world")

middleware中间件

在django中，中间件其实就是一个类，在请求到来和结束后，django会根据自己的规则在合适的时机执行中间件中相应的方法。在django项目的settings模块中，有一个 MIDDLEWARE.
中间件中可以定义如下方法。

process_request(self,request)
process_view(self, request, callback, callback_args, callback_kwargs)
process_template_response(self,request,response)
process_exception(self, request, exception)
process_response(self, request, response)
以上方法的返回值可以是None和HttpResonse对象，如果是None，则继续按照django定义的规则向下执行，如果是HttpResonse对象，则直接将该对象返回给用户。

// 撰写中间件
from django.utils.deprecation import MiddlewareMixin
from django.shortcuts import HttpResponse
class Middle1(MiddlewareMixin):
    def process_request(self, request):
        print("m1.process_request")

    def process_response(self, request, response):
        print("m1.process_response")
        return response


class Middle2(MiddlewareMixin):
    def process_request(self, request):
        print("m2.process_request")

    def process_response(self, request, response):
        print("m2.process_response")
        return response


//在settings中注册
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',
    "my_middle.Middle1",
    "my_middle.Middle2",
]

// 执行结果
//m1.process_request
//m2.process_request
//执行视图函数
//m2.process_response
//m1.process_response

CBV操作

# 1.路由系统
urlpatterns = [
    url(r'^login.html$', views.Login.as_view()),
]

# 2.views类
"""
    get     查
    post    创建
    put     更新
    delete  删除
"""
# 根据request.method的方式自动执行对应的函数。
# 我们可以重写dispatch函数来实现类似装饰器的效果，dispatch内部根据反射来实现函数执行。
from django.views import View

class Login(View):
    def get(self,request):
        return render(request, "login.html")

    def post(self, request):
        name = request.POST.get("user")
        print(name)
        return HttpResponse("from post ")
    
    def dispatch(self, request, *args, **kwargs):
        print("-----before------")
        ret = super().dispatch(request,*args,**kwargs)
        print("-----after------")
        return ret

# # CBV应用装饰器
# django的bug，不能直接对类进行装饰，必须使用 method_decorator,把装饰器当作参数传进去。
from django.utils.decorators import method_decorator
@method_decorator(wrapper, name="post")