七、模板层（一）

一、序列化和反序列化

```

#coding=utf-8
from django.http import HttpResponse
from django.views import View
import jsonpickle

class User(object):
    def __init__(self,uname,pwd):
        self.uname = uname
        self.pwd = pwd

class IndexView(View):
    def get(self,request,*args,**kwargs):
        uname = request.GET.get('uname','')
        pwd = request.GET.get('pwd','')

        if uname=='zhangsan' and pwd=='123':
            user = User(uname,pwd)
            #{"py/object": "demo5.views.User", "uname": "zhangsan", "pwd": "123"}
            # ustr = jsonpickle.encode(user)

            # {"py/object": "demo5.views.User", "uname": "zhangsan", "pwd": "123"}
            ustr =jsonpickle.dumps(user)
            print ustr
            request.session['user'] = ustr

return HttpResponse('Get请求')

class GetSession(View):
    def get(self,request,*args,**kwargs):
        user = request.session.get('user','')
        # <demo5.views.User object at 0x0000000003D48588>
        # uuser = jsonpickle.decode(user)

        # <demo5.views.User object at 0x0000000003D1A0F0>
        uuser = jsonpickle.loads(user)
        print uuser
        return HttpResponse('User:%s'%uuser.uname)

```

#### 序列化部分字段

```
class User(object):
    def __init__(self,uname,pwd):
        self.uname = uname
        self.pwd = pwd

    def __getstate__(self):
        data = self.__dict__.copy()
        del data['pwd']
        return data

u = User('zhangsan','123')
s = jsonpickle.encode(u,unpicklable=False)
# jsonpickle.dumps(u,unpicklable=False)
print s
#{"uname": "zhangsan"}

在调用pickle.dump时，默认是对象的__dict__属性被存储，如果你要修改这种行为，可以在__getstate__方法中返回一个state。state将在调用pickle.load时传值给__setstate__
__setstate__(self, state)

一般来说,定义了__getstate__,就需要相应地定义__setstate__来对__getstate__返回的state进行处理。
```

二、通用视图

#### 使用方法

#### 配置URL
```
from django.conf.urls import url
from django.contrib import admin
import views
urlpatterns = [
url(r'^admin/', admin.site.urls),
url(r'^$', views.IndexView.as_view()),
]

```

#### 创建视图

```
#coding=utf-8
from django.http import HttpResponse
from django.views import View

class IndexView(View):
def get(self,request,*args,**kwargs):
return HttpResponse('Get请求')

def post(self,request,*args,**kwargs):
return HttpResponse('Post请求')

```

三、页面读取静态文件

#### Django读取静态文件方式
- settings.py文件中设置

```
STATIC_URL = '/static/'

STATICFILES_DIRS = [
    os.path.join(BASE_DIR,'static/imgs'),
    os.path.join(BASE_DIR,'static/css'),
    os.path.join(BASE_DIR,'static/js'),

]

```

#### 配置URL

```
from django.conf.urls import url
from django.contrib import admin
import views
urlpatterns = [
url(r'^admin/', admin.site.urls),
url(r'^index.html$',views.index_view)
]

```

#### 创建视图

```
def index_view(request):
return render(request,'index.html')

```

#### 创建模板

```
{% load staticfiles %}
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>

</body>
</html>

```

四、模板标签渲染原理

#### 配置URL
1. 项目包/urls.py
```
from django.conf.urls import url, include
from django.contrib import admin

urlpatterns = [
url(r'^admin/', admin.site.urls),
url(r'^student/', include('student.urls')),
]

```
2. 应用包/urls.py
```
#coding=utf-8

from django.conf.urls import url
import views

urlpatterns=[
url(r'^query1/$',views.query_view1)
]

```

#### 创建视图

- 方式1：
```
# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.http import HttpResponse
from django.shortcuts import render

from django.template import Template,Context

# Create your views here.
def query_view1(request):
    t = Template('hello:{{name}}')
    c = Context({'name':'zhangsan'})
    renderStr = t.render(c)

return HttpResponse(renderStr)

```

- 方式2:

```
# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.http import HttpResponse
from django.shortcuts import render

from django.template import Template,Context

# Create your views here.
def query_view1(request):
    with open('templates/index.html','rb') as fr:
        content = fr.read()
    t = Template(content)
    c = Context({'name':'lisi'})
    renderStr = t.render(c)

return HttpResponse(renderStr)

```

#### 创建模板
```

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    hello:{{ name }}
</body>
</html>
```

- 方式3：

#### 创建视图
```
# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.http import HttpResponse
from django.shortcuts import render

from django.template import Template,Context
from django.shortcuts import loader

# Create your views here.
def query_view1(request):
t = loader.get_template('index.html')
renderStr = t.render({'name':'wangwu'})

return HttpResponse(renderStr)

```

- 方式4：

#### 配置视图
```
# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.http import HttpResponse
from django.shortcuts import render

# Create your views here.
def query_view1(request):
return render(request,'index.html',{'name':'zhaoliu'})

```

五、自定义过滤器

#### 配置URL
```
from django.conf.urls import url, include
from django.contrib import admin

urlpatterns = [
url(r'^admin/', admin.site.urls),
url(r'^student/', include('student.urls')),
]

#coding=utf-8

from django.conf.urls import url
import views

urlpatterns=[
url(r'^$',views.index_view)
]

```

#### 创建视图

```
# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.shortcuts import render

# Create your views here.
def index_view(request):
content = '''####过滤器'''
return render(request,'index.html',{'content':content})

```

#### 创建模板
```
{% load filter_mark %}
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    {{ content|md|safe }}

</body>
</html>

```

#### 创建自定义过滤器
1. 在应用包下创建一个名为"templatetags"的python package
2. 在包中创建一个自定义的py文件

pip install markdown

```
#coding=utf-8

from django.template import Library

#实例名必须是register
register = Library()

@register.filter
def md(value):
import markdown
return markdown.markdown(value)

```

#### 截取字符串功能
```
#coding=utf-8

from django.template import Library

@register.filter
def splitstr(value,args):
    start,end = args.split(',')
    content = value.encode('utf-8').decode('utf-8')
    return content[int(start):int(end)]

```
- index.html页面
```
{% load filter_mark %}
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>

</body>
</html>

```