Python的平凡之路（19）

一、Django请求生命周期

 

对于所有的web框架来说本质就是一个socket服务端，浏览器是socket客户端

 

 

 

                                                                                                （完整的一个Django请求生命周期）

 

                                                                                            （Django的路由系统）

   -> URL对应关系（匹配） -> 视图函数 -> 返回用户字符串

   -> URL对应关系（匹配） -> 视图函数 -> 打开一个HTML文件，读取内容

 

 

二、创建django projcet

 

django-admin startproject mysite  #开始项目

          ..

          mysite

               mysite

                    - 配置文件

                    - url.py

                    - settings.py

 

  cd mysite

  python manage.py startapp cmdb  #开始一个app

 

          mysite

               mysite

                    - 配置文件

                    - url.py

                    - settings.py

               cmdb

                    - views.py

                    - admin.py

                    - models.py # 创建数据库表

 

python3.5 manage.py runserver  #启动

 

 三、配置

 

模板路径   /templates/   记着加s

          

静态文件路径  /static/

         

# CSRF

 

四、编写程序

 

a. url.py

 

               /index/    ->   func

from cmdb import views
urlpatterns = [
    url(r'^login/$', views.login),
    url(r'^index/$', views.index),
    url(r'^lists/$', views.lists),
    url(r'^add/$', views.add),
]

b. views.py

 

def func(request):

                   

                    # 包含所有的请求数据

                    ...

                    return HttpResponse('字符串')

                    return render(request, 'index.html', {''})

                    retrun redirect('URL’)

def user_list(request,chose_id):
    return HttpResponse(chose_id)

 

c. 模板语言

              

 return render(request, 'index.html', {'li': [11,22,33]})

 

               {% for item in li %}

                    <h1>{{item}}</h1>

               {% endfor %}%

     

 ***********  索引用点 **********

               <h2> {{item.0 }} </h2>

 

五、路由系统，URL

     

1、url(r'^index/', views.index),    

      url(r'^home/', views.Home.as_view()),

    

2、url(r'^detail-(\d+).html', views.detail),  

     

3、url(r'^detail-(?P<nid>\d+)-(?P<uid>\d+).html', views.detail)

 

        PS:

               def detail(request, *args,**kwargs):

                    pass

 

        实战：

               a.

                    url(r'^detail-(\d+)-(\d+).html', views.detail),

 

                    def func(request, nid, uid):

 

                         pass

 

                    def func(request, *args):

                         args = (2,9)

 

 

                    def func(request, *args, **kwargs):

                         args = (2,9)

 

               b.

                    url(r'^detail-(?P<nid>\d+)-(?P<uid>\d+).html', views.detail)

 

                    def func(request, nid, uid):

                         pass

 

                    def funct(request, **kwargs):

                         kwargs = {'nid': 1, 'uid': 3}

 

                    def func(request, *args, **kwargs):

                         args = (2,9)

 

 4、 name

 

          

对URL路由关系进行命名， ***** 以后可以根据此名称生成自己想要的URL *****

 

          url(r'^asdfasdfasdf/', views.index, name='i1'),

          url(r'^yug/(\d+)/(\d+)/', views.index, name='i2'),

          url(r'^buy/(?P<pid>\d+)/(?P<nid>\d+)/', views.index, name='i3'),

          

            def func(request, *args, **kwargs):

                           from django.urls import reverse

                           url1 = reverse('i1')                              # asdfasdfasdf/

                           url2 = reverse('i2', args=(1,2,))                 # yug/1/2/

                           url3 = reverse('i3', kwargs={'pid': 1, "nid": 9}) # buy/1/9/

 

         

 xxx.html

 

               {% url "i1" %}               # asdfasdfasdf/

               {% url "i2" 1 2 %}           # yug/1/2/

               {% url "i3" pid=1 nid=9 %}   # buy/1/9/

 

          

注：

               # 当前的URL

               request.path_info

 

5、多级路由

 

          project/urls.py

               from django.conf.urls import url,include

               from django.contrib import admin

 

               urlpatterns = [

                    url(r'^cmdb/', include("app01.urls")),

                    url(r'^monitor/', include("app02.urls")),

               ]

 

          app01/urls.py

               from django.conf.urls import url,include

               from django.contrib import admin

               from app01 import views

 

               urlpatterns = [

                    url(r'^login/', views.login),

               ]

 

          app02/urls.py

               from django.conf.urls import url,include

               from django.contrib import admin

               from app02 import views

 

               urlpatterns = [

                    url(r'^login/', views.login),

               ]

 

6、默认值（欠）

 

7、命名空间（欠）

 

 

六、视图

 

1、获取用户请求数据

          request.GET

          request.POST

          request.FILES

          PS:

               GET:获取数据                    

               POST:提交数据

 

2、checkbox等多选的内容

      request.POST.getlist()

     

 

3、上传文件

          # 上传文件,form标签做特殊设置

          obj = request.FILES.get('fafafa')

          obj.name

          f = open(obj.name, mode='wb')

          for item in obj.chunks():

               f.write(item)

          f.close()

 

     

4、FBV & CBV

        function base view

 

          url.py

               index -> 函数名

 

          view.py

               def 函数(request):

                    ...

          ====》

          /index/ -> 函数名

 

          /index/ -> 类

 

          ====》

 

          建议：两者都用

 

 5、装饰器

          欠

 

 

七、模板

 

 

 

八、ORM操作

     

select * from tb where id > 1     

# 对应关系     

models.tb.objects.filter(id__gt=1)     

models.tb.objects.filter(id=1)    

models.tb.objects.filter(id__lt=1)

 

实战连接数据库：        

a. 创建类，先写类

          from django.db import models

 

          # app01_userinfo

          class UserInfo(models.Model):

               # id列，自增，主键

               # 用户名列，字符串类型，指定长度

               username = models.CharField(max_length=32)

               password = models.CharField(max_length=64)

 

  b. 注册APP

 

          INSTALLED_APPS = [

               'django.contrib.admin',

               'django.contrib.auth',

               'django.contrib.contenttypes',

               'django.contrib.sessions',

               'django.contrib.messages',

               'django.contrib.staticfiles',

               'app01',

          ]

 

c. 执行命令

          python manage.py  makemigrations

          python manage.py  migrate

 

     

d. ********** 注意 ***********

          Django默认使用MySQLdb模块链接MySQL

          主动修改为pymysql，在project同名文件夹下的__init__文件中添加如下代码即可：

               import pymysql

               pymysql.install_as_MySQLdb()

 

1）. 根据类自动创建数据库表

          # app下的models.py

 

          python manage.py  makemigrations

          python manage.py  migrate

 

 

          字段：

               字符串类型

 

 

               数字

 

 

               时间

 

 

               二进制

 

               自增（primary_key=True）

 

          字段的参数：

               null               -> db是否可以为空

               default            -> 默认值

               primary_key        -> 主键

               db_column          -> 列名

               db_index           -> 索引

               unique                  -> 唯一索引

               unique_for_date    ->

               unique_for_month

               unique_for_year

               auto_now           -> 创建时，自动生成时间

               auto_now_add       -> 更新时，自动更新为当前时间

 

                    # obj = UserGroup.objects.filter(id=1).update(caption='CEO')

                    # obj = UserGroup.objects.filter(id=1).first()

                    # obj.caption = "CEO"

                    # obj.save()

 

               choices                 -> django admin中显示下拉框，避免连表查询

               blank             -> django admin是否可以为空

               verbose_name      -> django admin显示字段中文

               editable          -> django admin是否可以被编辑

               error_messages    -> 错误信息欠

               help_text         -> django admin提示

               validators            -> django form ,自定义错误信息（欠）

               创建 Django 用户：python manage.py createsuperuser

     

2）. 根据类对数据库表中的数据进行各种操作

 

          一对多：

 

               a. 外检

               b.

                    外键字段_id

               c.

                    models.tb.object.create(name='root', user_group_id=1)

               d.

                   userlist = models.tb.object.all()

                    for row in userlist:

                         row.id

                         row.user_group_id

                         row.user_group.caption

 

九、实例

详见Pycharm