反向生成url

反向生成url 一.常规的url系统：

from django.conf.urls import url
from django.shortcuts import HttpResponse, render, redirect
def index(request):
    return HttpResponse("进入index")
def text(requext):
    return HttpResponse("进入text")
urlpatterns = [
    # url(r'^admin/', admin.site.urls),   
    url(r'^index/', index),
    url(r'^text/', text),
]

执行过程如下图：

从这里我们知道常规的url是需要在地址栏中将访问的地址对应着urlpatterns中的地址吻合进行访问，所以当出现下面这种情况的话就对访问的友好度极低：

urlpatterns = [
    # url(r'^admin/', admin.site.urls),
    url(r'^arya/', site.urls),
    url(r'^index/asdas/asdas/da/asd/as', index),
    url(r'^text/dasd/asd/asd/sad/asd/as/d', text),
]

二、反向生成url 1.reverse方法

def index(request):
    from django.urls import reverse
    test_url = reverse('xx')
    print(test_url) 
    return HttpResponse("进入index")
def text(requext):  
    return HttpResponse("进入text")
urlpatterns = [
    url(r'^index/', index,),
    url(r'^text/dasd/asd/asd/sad/asd/as/d', text,name='xx'),
]

打印的结果：

/text/dasd/asd/asd/sad/asd/as/d

这个url就是text的url路径，所以通过给其定义一个name就可以反向生成一个其对应的url地址

2.带参数的url的反向生成：

def index(request):
    from django.urls import reverse
    test_url = reverse('xx',args=(2,9))
    return redirect(test_url)

def text(requext,*args,**kwargs):

    return HttpResponse("进入text")
urlpatterns = [
    url(r'^index/', index,),
    url(r'^text/dasd/asd/(\d+)/sad/(\d+)/as/d', text,name='xx'),
]

这里需要注意的是当text中的url中需要传参所以对应的text视图函数中就需要*args,**kwargs接受参数

3.带命名的正则url

def index(request):
    from django.urls import reverse
    test_url = reverse('xx',kwargs={'a1':8,'a2':99})
    return redirect(test_url)

def text(requext,*args,**kwargs):

    return HttpResponse("进入text")
urlpatterns = [
    url(r'^index/', index,),
    url(r'^text/dasd/asd/(?P<a1>\d+)/sad/(?P<a2>\d+)/as/d', text,name='xx'),
]

这里和常规带参数的唯一不同reverse方法中是传递一个kwargs的键值对的字典

4.前端显示反向url test_url = reverse('xx',kwargs={'a1':8,'a2':99})

渲染效果：

test_url = reverse('xx',args=(2,9))

渲染效果：

反向生成url嵌套(namespance) 1.单层嵌套

def index(request):
    from django.urls import reverse
    test_url = reverse('x1:txt')
    return HttpResponse("index")

def text(request,*args,**kwargs):
    return HttpResponse('text')
urlpatterns = [

    url(r'^app01/', ([
        url(r'^index/', index,name='idx'),
        url(r'^test/', text,name='txt')
                     ],'x1','x2'),),
]

上述的url中相当于嵌套了一层，且有namespance(x1,x2),所以对于这类的url的反向生成需要如下操作：

test_url = reverse('x1:txt')

2.多层嵌套

def index(request):
    from django.urls import reverse
    test_url = reverse('x1:txt')
    return HttpResponse("index")
def text(request,*args,**kwargs):
    return HttpResponse('text')
urlpatterns = [
    url(r'^app01/', ([
        url(r'^userinfo/', (
            [
            url(r'^index/', index,name='idx'),
            url(r'^test/', text,name='txt')
                         ],None,None)),
     ] ,'x1','x2')),
    ]

这里双层嵌套的url,但是内层的namespance都是空所以它会往外层找，所
以反向生成的代码：

test_url = reverse('x1:txt')

同时当内层namespance有值时：

urlpatterns = [
    # url(r'^admin/', admin.site.urls),
    # url(r'^arya/', site.urls),
    url(r'^app01/', ([
        url(r'^userinfo/', (
            [
            url(r'^index/', index,name='idx'),
            url(r'^test/', text,name='txt')
                         ],'x2','x2')),
     ] ,'x1','x1')),
    ]

反向生成url代码就是如下：

def index(request):
    from django.urls import reverse
    test_url = reverse('x1:x2:txt')
    print(test_url)
    return HttpResponse("index")

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

    return HttpResponse('text')

所以通过上述的案例可以知道，不管url嵌套多少层，其反向生成url的规则是一样的，遵循的规则就是namespance从外层以冒号连接至最后一层。