Django视图层与模板层实例详解

class HttpResponse(HttpResponseBase):
	pass

def render(...):
    pass
    return HttpResponse(content, content_type, status)

def redirect(to, *args, permanent=False, **kwargs):
    redirect_class = HttpResponsePermanentRedirect if permanent else HttpResponseRedirect
    return redirect_class(resolve_url(to, *args, **kwargs))

def home(request):
    import json
    user_dict = {'name': 'jason老师', 'pwd': 123, 'hobby': ['read', 'run', 'music']}
    json_user_dict = json.dumps(user_dict, ensure_ascii=False)
    return render(request, 'home.html', json_user_dict)

from django.http import JsonResponse
def home(request):
    JsonResponse(user_dict)  # 

class JsonResponse(HttpResponse):
    def __init__(self, data, encoder=DjangoJSONEncoder, safe=True,
                 json_dumps_params=None, **kwargs):
        if json_dumps_params is None:
            json_dumps_params = {}
        kwargs.setdefault('content_type', 'application/json')
        data = json.dumps(data, cls=encoder, **json_dumps_params)
        super().__init__(content=data, **kwargs)

JsonResponse(user_dict, json_dumps_params={'ensure_ascii':False})

<form method="post" enctype="multipart/form-data">
</form>

files = request.FILES  # 后端接收文件数据只能用FILES方法，不能用POST

# views.py
def home(request):
    return render(request, 'home.html')
# urls.py
path('home/', views.home)

# views.py
from django impost views
class MyView(views.View):
    def get(self, request):
        return HttpResponse('我是CBV的get方法')
    def post(self, request):
        return HttpResponse('我是CBV的post方法')
# urls.py
path('func/', views.MyView.as_view())

    def as_view(...):
          def view(...):
              pass
          return view

    def view(request, *args, **kwargs):
        self = cls(**initkwargs)    # 这里的cls使我们自己写的类MyView  self是MyView实例化出来的

    def dispatch(self, request, *args, **kwargs):  
    # dispatch是绑定给对象的方法，self相当于是我们前文提到的obj
        if request.method.lower() in self.http_method_names:
            handler = getattr(self, request.method.lower(),self.http_method_not_allowed)
           # 反射  通过请求字符串去调用真正的请求方法   这里的请求是post所以handler是post
        else:
            handler = self.http_method_not_allowed
        return handler(request, *args, **kwargs)  # 即post(request, *args, **kwargs)
        # 此时 view()函数的返回值为： 
         #  def view(request, *args, **kwargs):
         #        return self.post(request, *args, **kwargs)

def home(request):
    name = 'kevin'
    age = 19
    return render(request, 'home.html', {'name':name, 'age': age})

def home(request):
    name = 'kevin'
    age = 19
    return render(request, 'home.html', locals())

    <p>统计长度：{{ s|length }}</p>
    <p>加法运算：{{ s|add:'NB' }}</p>
    <p>文件大小：{{ file_size|filesizeformat }}</p>
    <p>数据切片：{{ s|slice:'3' }}</p>
    <p>字符截取：{{ s|truncatechars:3 }}</p>		# 以字符为单位 多出的部分用...代替
    <p>单词截取：{{ words|truncatewords:3 }}</p>    #以单词为单位 多出的部分用...代替
    <p>语法转义：{{ html_tag|safe }}</p>		# 识别字符串中的html标签 并渲染(默认是不识别)
#html默认不识别后端传过来的字符串标签，指定safe可以让其识别并渲染
#除了在传给前端之后让前端识别 我们也可以在后端处理之后再传给前端，这样前端就不用识别了(意味着html页面上的数据不一定非要在html文件中编写了 也可以通过后端传入)
    from django.utils.safestring import mark_safe
        script_tag1 = '<script>alert(666)</script>'
        res = mark_safe(script_tag1)  # 直接把res传给前端

'''
django模板语法中的符号就两个 一个{{}} 一个{%%}
	需要使用数据的时候 {{}}
	需要使用方法的时候 {%%}
'''  

from django.template import Library
	register = Library()

@register.filter(name='myfilter')
    def my_add(a, b):
        return a + b

@register.simple_tag(name='mt')
    def func(a, b, c, d):
        return a + b + c + d

@register.inclusion_tag(filename='it.html')
    def index(n):
        html = []
        for i in range(n):
            html.append('第%s页'%i)
        return locals()

{% load mytag %}
{{ i|myfilter:1 }}
{% mt 1 2 3 4 %}
{% index 10 %}

{% include 'menu.html' %}