Python全栈8 - Django 开发与进阶

8、Django 开发与进阶

1、Django开发－基础篇

1-1 Django 概述

优点：

  自主管理后台

  自带ORM

  Django的错误提示

 

安装：

  Win:pip install django==1.7.5

 Lin: sudo pip install django

 

升级:

  pipinstall -U django

 

配置环境变量：

  在Win中，C:\Python27\Lib\site-packages\django\bin

 

>django-adminstartproject myProject  // 创建项目名

>cd myProject 

>django-admin startapp myApp // 创建应用

在myProject目录中settings.py添加应用'myApp'：

INSTALLED_APPS = (

   'django.contrib.admin',

   'django.contrib.auth',

   'django.contrib.contenttypes',

   'django.contrib.sessions',

   'django.contrib.messages',

   'django.contrib.staticfiles',

    'myApp',

)

 

启动：

>python manage.pyrunserver

localhost:8000

 

>python manage.py runserver 0.0.0.0:8000

192.168.245.132:8000

 

0.0.0.0让其它电脑可连接到开发服务器，8000为端口号。如果不说明，那么端口号默认为8000

 

1-2视图开发及URL配置

Django可识别的视图需要满足两个条件：

  1）第一个参数的类型：HttpRequest

  2）返回HttpRespnse实例

 

视图函数开发实例演示：

代码：

from django.http import HttpResponse

 

# Create your views here.

def hello(request):

           returnHttpResponse("hello world")

 

从输入url地址到产生页面内容的流程：

  在浏览器地址中输入url地址

  访问settings.py中 ROOT_URLCONF= 'myProject.urls'

  查找匹配urls.py中的路径，(r'^hello/$',hello)

  在views.py中找到视图函数，返回一个HttpRespnse对象

  转为合适的形式，在网页中展示

 

在url中的动态配置– 正则

 

在settings.py中设置出错页面：

  #SECURITY WARNING: don't run with debug turned on in production!

DEBUG = True

 

1-3 Django 模板语法及使用

模板– 文本，用于分离文档的表现形式和内容，通常用于生产HTML

 

使用：

  可以模板代码字符串创建一个Template对象

  调用模板对象的render方法，并且传入一套变量context

代码：

C:\Users\Administrator\work\PythonSpace\Django\myProject>pythonmanage.py shell

Python 2.7.11 (v2.7.11:6d1b6a68f775, Dec  5 2015, 20:32:19) [MSC v.1500 32 bit (

Intel)] on win32

Type "help", "copyright", "credits" or"license" for more information.

(InteractiveConsole)

>>> from django import template

>>> t = template.Template('hello{{name}}')

>>> c = template.Context({'name':'django'})

>>> print t.render(c)

hello django

>>> 

 

在settings.py中添加如下代码– 告诉项目你要使用'templates'

import os

TEMPLATE_DIRS = os.path.join(os.path.dirname(__file__), 'templates')

验证：

>>> from django.template.loader import get_template

>>> t = get_template('2.html')

>>> t

//说明模板加载成功了

>>> 

 

方法二：一个简单的方法

直接在views.py中，添加

from django.shortcuts importrender_to_response

 

def views(request):

           returnrender_to_response('2.html',{"name":"hello"})

 

模板继承

//2.html

<

          

{% block content %}

Hello World

{% endblock %}

 

//3.html

{% extends 2.html %}

 

{% block content %}

{% endblock %}

 

模板语法：

<

          

Y X

Hello {{name}}

 

           {%for item in itemList%}

          

• {{item }}

   {% endfor %}

 

{% if status %}

I like python

{% else %}

I like django

{% endif %}

 

{% ifequal a b %}

 

{% endifequal%}

 

{{ name | upper }} //过滤器，管道字符

{{ name | lower }}

 

1-4 模型开发与数据库交互

在myProject -> settings.py中，配置数据库

DATABASES = {

   'default': {

       'ENGINE': 'django.db.backends.mysql',

       'USER': 'root',

       'PASSWORD': 'root',

       'NAME': djangodb,

       'HOST': 'localhost',

   }

}

 

实现一个数据模型

代码：

#models.py

from django.db import models

 

# Create your models here.

class Mysite(models.Model):

           tile= models.CharField(max_length=100)

           url= models.URLField()

           author= models.CharField(max_length=100)

           num= models.IntegerField(max_length=10)

 

在工程目录下，

>python manage.py validate  //验证

>python manage.py sqlall myAPP  //所执行的SQL语句

>python manage.py syncdb  //同步数据库

数据处理：

1）基本数据访问

2）插入和更新数据

3）数据过滤

4）数据排序

5）更新多个对象，删除对象

 

C:\Users\Administrator\work\PythonSpace\Django\myProject>pythonmanage.py shell

Python 2.7.11 (v2.7.11:6d1b6a68f775,Dec  5 2015, 20:32:19) [MSC v.1500 32 bit(

Intel)] on win32

Type "help","copyright", "credits" or "license" for moreinformation.

(InteractiveConsole)

>>> from myApp.models import *

>>> m =Mysite.objects.all()

>>> m

[]

//插入

>>> m =Mysite(title='django',num=2)

>>> m.save()

//查询

>>> m = Mysite.objects.all()

>>> m

[]

>>> m[0].title

u'django'

>>> 

//数据过滤

>>> m=Mysite.objects.get(num=2)

>>> m

>>> m.title

u'django'

>>> 

//排序

>>> m =Mysite(title='django',num=1)

>>> m.save()

>>> m = Mysite(title='django',num=3)

>>> m.save()

>>> m =Mysite(title='django',num=9)

>>> m.save()

>>> m = Mysite.objects.all()

>>> m

[, , ,

ite: Mysite object>]

>>> 

>>> m[0].num

2L

>>> m = Mysite.objects.all().order_by("num")

>>> m

[, , ,

ite: Mysite object>]

>>> m[0].title

u'django'

>>> m[0].num

1L

>>> 

//降序

>>> m =Mysite.objects.all().order_by("-num")

>>> m[0].num

9L

>>> 

//更新

>>> m = Mysite.objects.get(num=2)

>>> m

>>> m.title = 'python'

>>> m.save()

>>> m = Mysite.objects.get(num=2)

>>> m.title

u'python'

>>> 

//删除

>>> m.delete()

>>> m = Mysite.objects.get(num=2)

Traceback (most recent call last):

 File "", line 1, in

 File"C:\Python27\lib\site-packages\django\db\models\manager.py", line 92,in

manager_method

   return getattr(self.get_queryset(), name)(*args, **kwargs)

 File"C:\Python27\lib\site-packages\django\db\models\query.py", line 357,in g

et

   self.model._meta.object_name)

DoesNotExist: Mysite matching query doesnot exist.

>>> 

//查询结果的条件限制

>>> m=Mysite.objects.all()

>>> m

[, , ]

>>> m=Mysite.objects.all()[0:2]

>>> m

[, ]

>>> 

 

1-5 Django 的后台管理及表单类介绍

Django 的自动管理界面

通过读取你模式中的元数据，提供一个强大而且可以使用的界面。

 

1）在后台管理中添加用户

2）修改用户权限

3）管理模型数据

代码：

// admin.py

from django.contrib import admin

from myApp.models import *

# Register your models here.

admin.site.register(Mysite)

 

  //models.py

           def__unicode__(self):

                     returnself.title

 

4）使用django自有的表单类

//forms.py

from django import forms

 

class Mybook(forms.Form):

           name= forms.CharField()

           author= forms.CharField()

           date= forms.CharField()

 

//views.py

from myApp.forms import *

from django.http import HttpResponse

from django.shortcuts importrender_to_response

 

def book(request):

           ifrequest.method == 'POST':

                     form= Mybook(request.POST)

                     ifform.is_valid():

                                data= form.cleaned_data

                                name= data["name"]

                             returnHttpResponse(name)

 

           form= Mybook()

           returnrender_to_response('book.html',{'form':form})

 

//urls.py

from django.conf.urls import patterns,include, url

from django.contrib import admin

from myApp.views import *

 

urlpatterns = patterns('',

    #Examples:

    #url(r'^$', 'myProject.views.home', name='home'),

    #url(r'^blog/', include('blog.urls')),

   url(r'^admin/', include(admin.site.urls)),

           (r'^book/$',book)

)

 

//book.html

<

          

          

                     {{form.as_p }}

                    

          

 

 

 

 

 

2、Django开发 - 进阶篇

2-1 高级视图及URL配置

1）URL简写

  导入视图函数的方法

# urls.py

# frommyApp.views import *  //传统的导入视图函数方法

urlpatterns = patterns('myApp.views', //随着后期视图函数的增多，使用新的导入方法，便于后期URL的管理

    (r'^hello/$',hello),

)

 

  +=  //使url配置变得结构化

# hello

urlpatterns += patterns('',

    (r'^hello/$',hello),

    (r'hello/(\d+)/$',hello1),

)

 

# book

urlpatterns += patterns('',

     (r'^book/$',book),

)

 

2）URL命名组 – 为url配置添加一个相关的名字，让这个路径显得更加直观

urlpatterns += patterns('',

     (r'^book/(?P\d+)/(?P\d+)/$',book),

)

请求时：

hello(request,year=2016,month=3)

 

3）高级视图

法一：

//views.py

#def view1(request):

#         returnrender_to_response('1.html')

#def view2(request):

#         returnrender_to_response('2.html')

 

def views(request,template_name):

           returnrender_to_response(template_name)

 

//urls.py

urlpatterns += patterns('',

#         (r'^view1/$',view1),

#         (r'^view2/$',view2),

 

           (r'^view1/$',views,{'template_name':1.html}),

           (r'^view2/$',views,{'template_name':2.html}),

)

 

法二：利用Python中嵌套函数

  提取公共部分，而不影响每个视图函数的各自的逻辑

//views.py

def view1(request):

           returnrender_to_response('1.html')

def view2(request):

           returnrender_to_response('2.html')

def views(func):

           defview(request):

                     #do something

                     returnfunc(request)

           returnview

 

//urls.py

urlpatterns += patterns('',

           (r'^view1/$',views(view1)),

           (r'^view2/$',views(view2)),

)

 

2-2 高级模型

1）外键的获取 - forignkey

 

2）多对多的获取 – many-to-many

 

3）自定义Manager – 对经常使用的查询结果进行封装

 

4）自定义QuerySet - 对经常使用的查询对象进行封装

 

2-3 高级模板

创建模板库的步骤：

1.          决定模板库的位置，将它作为app来使用

2.          创建templatetags目录

3.          创建__init__.py和extras.py文件

__init__.py是来告诉python程序这里面装的是Python代码

extras.py是来写模板库代码

 

1）过滤器的实现

from django import template

 

register = template.Library()

 

@register.filter(name="cut")

def myCut(value,arg):

           returnvalue.replace(arg,"!")

 

2）自定义标签

标签内容：

  {{current_time %Y-%m-%d %H:%M:%S }}

 

2-4 通用视图

1）对静态页面 - 减少了代码量，不必写视图函数

# urls.py

from django.views.generic import TemplateView //简单的静态页面的路径

 

urlpatterns += patterns('',

     (r'^about/$',TemplateView.as_view(template_name='hello.html')),

)

 

2）对渲染页面 – 将数据库的简单数据渲染到模板上

# urls.py

from django.views.generic.list importListView

from myApp.models import *

 

book_info = {

           'queryset':Mysite.objects.all,

           'template_name':'hello.html'

}

 

urlpatterns += patterns('',

           (r'^about/$',ListView.as_view(**book_info)),

)

 

3）处理数据过滤 – 写一个自己的类

 

2-5 缓存系统

1）内存缓存

# settings.py

CACHE_BACKEND = 'memcache://127.0.0.1:12111/'

 

2）数据库缓存

>python manage.py createcachetablemycache

 

# settings.py

CACHE_BACKEND = 'db://mycache'

 

3）文件缓存

# settings.py

CACHE_BACKEND = 'file:///usr/local/tmp'

 

4）缓存系统应用

>ab –n 1000 http://localhost:8000/hello  # 测试访问1000个连接需要多长时间

 

# 2-5-1 django自带的小缓存

from django.core.cache import cache

def view(request):

           ifcache.get('book'):

                     b=cache.get('book')

           else:

                     b=Book.objects.all()

                     cache.set('book',b)

           returnrender_to_response('1.html',{'book':b})

 

# 可以缓存整个视图的方法

from django.decorators.cache importcache_page

@cache_page(60*15)  #配置过期的时间

def view(request):

           b=Book.objects.all()

           returnrender_to_response('1.html',{'book':b})

 

2-6 中间件

常见的中间件

MIDDLEWARE_CLASSES = (

    'myApp.myMiddleware.MyMiddleware', #自定义中间件

   'django.contrib.sessions.middleware.SessionMiddleware',#用来支持django中会话操作，只有打开了这个中间件才能在项目中使用会话

   'django.middleware.common.CommonMiddleware',#可以很方便的使用一些功能

    #'django.middleware.csrf.CsrfViewMiddleware', #防止Csrf的攻击

   'django.contrib.auth.middleware.AuthenticationMiddleware', #认证浏览器的User登录一些信息

   'django.contrib.auth.middleware.SessionAuthenticationMiddleware',

   'django.contrib.messages.middleware.MessageMiddleware',

   'django.middleware.clickjacking.XFrameOptionsMiddleware',

   'django.middleware.gzip.GZipMiddleware', #用来压缩浏览器返回的内容，减少服务器使用的带宽

    #'django.middleware.http.SetRemoteAddrFromForwardedFor', # 处理反向代理，若要获得反向代理的IP值，就需要这个中间件去获得

 

解析中间件：

1.__init__ #初始化的操作

2.process_request  #视图函数请求之前的操作

3.process_view #视图函数接受了request请求之后

4.process_response #处理完view逻辑后的response

5.process_exception #处理异常的

 

自定义中间件实例演示

# myMiddleware.py

class MyMiddleware(object):

           def__init__(self):

                     print'Hello, this is my middleware!'

 

           defprocess_view(self,request,func, args,kwargs):

                     printfunc

 

 

 

 

3、Django开发 - API 设计

3-1 Rest-Framework概述

restful简介

  一种软件架构风格，设计风格而不是标准，只是提供了一种设计原则和约束条件

>pip install djangorestframework

Add 'rest_framework' toyour INSTALLED_APPS setting.

INSTALLED_APPS = (

    ...

    'rest_framework',

)

 

3-2 序列化——第一个API，返回JSON数据

//models.py

class Book(models.Model):

           name= models.CharField(max_length=100)

           title= models.CharField(max_length=100)

           author= models.CharField(max_length=100)

 

// serializers.py

from myApp.models import Book

from rest_framework import serializers

 

classBookSerializer(serializers.Serializer):

           classMeta:

                     model= Book

                     field= ('name','title','author')

                    

           #name = serializers.CharField(max_length=100)

           #title = serializers.CharField(max_length=100)

           #author = serializers.CharField(max_length=100)

 

           defrestore_object(self,attrs,instance=None):

                     ifinstance:

                                instance.title= attrs['title']

                                instance.name= attrs['name']

                                instance.author= attrs['author']

                                returninstance

                     returnBook(**attrs)

 

在python shell中进行实验：

C:\Users\Administrator\work\PythonSpace\Django\myProject>pythonmanage.py syncdb

 

C:\Users\Administrator\work\PythonSpace\Django\myProject>pythonmanage.py shell

Python 2.7.11 (v2.7.11:6d1b6a68f775,Dec  5 2015, 20:32:19) [MSC v.1500 32 bit(

Intel)] on win32

Type "help","copyright", "credits" or "license" for moreinformation.

(InteractiveConsole)

>>> from myApp.models import Book

>>> b = Book(name='django1',title=’DJ1’,author=’yx’)

>>> b.save()

>>> from myApp.serializers import*

>>> from rest_framework.renderersimport JSONRenderer

>>> from rest_framework.parsersimport JSONParser

>>> b = Book.objects.get(id=1)

>>> book = BookSerializer(b)

>>> book.data

{'author': u'yx', 'name': u'django1','title': u'DJ1'}

>>> c =JSONRenderer().render(book.data)

>>> c

'{"name":" django1","title":"DJ1","author":" yx"}'

>>> 

 

 

//views.py

from django.http importStreamingHttpResponse

from rest_framework.renderers importJSONRenderer

from myApp.models import Book

from myApp.serializers importBookSerializer

 

class JSONResponse(StreamingHttpResponse):

           def__init__(self,data,**kwargs):

                     content= JSONRenderer().render(data)

                     kwargs['content_type']= 'application/json'

                     super(JSONResponse,self).__init__(content,**kwargs)

 

def book_list(request,num):

           ifrequest.method == 'GET':

                     b= Book.objects.get(id=num)

                     ser= BookSerializer(b)

                     returnJSONResponse(ser.data)

 

3-3 基于类的视图

1）将视图函数改写为基于类的视图

//views.py

from rest_framework import APIView

from rest_framework import Response

 

class BookList(APIView):

           defget(self,request,format=None):

                     books= Book.objects.all()

                     ser= BookSerializer(books,many=True)

                     returnResponse(ser.data)

 

           defpost(self,request,format=None):

                     ser= BookSerializer(request.DATA)

                     ifser.is_valid():

                                ser.save()

                                returnResponse(ser.data)

                     returnResponse(ser.errors)

 

class BookDetail(APIView):

           defget(self,request,num,format=None):

                     books= Book.objects.all(id=num)

                     ser= BookSerializer(b)

                     returnResponse(ser.data)

 

 

//urls.py

urlpatterns += patterns('',

           (r'^book/$',BookList.as_view()),

           (r'^book/(\d+)',BookDetail.as_view()),

)

好处：将get和post分离，利于后期的拓展和维护

 

2）通用视图

from rest_framework import generics

 

class BookList(APIView):

           queryset=Book.objects.all()

           serializer_class=BookSerializer

 

3-4 API权限管理和设置