反向生成url

反向生成url

一.常規的url系統：

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

執行過程如下圖：

從這裡我們知道常規的url是需要在地址欄中將訪問的地址對應著urlpatterns中的地址吻合進行訪問，所以當出現下麵這種情況的話就對訪問的友好度極低：

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("進入index")
def text(requext):  
    return HttpResponse("進入text")
urlpatterns = [
    url(r'^index/', index,),
    url(r'^text/dasd/asd/asd/sad/asd/as/d', text,name='xx'),
]

列印的結果：

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

這個url就是text的url路徑，所以通過給其定義一個name就可以反向生成一個其對應的url地址

2.帶參數的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("進入text")
urlpatterns = [
    url(r'^index/', index,),
    url(r'^text/dasd/asd/(\d+)/sad/(\d+)/as/d', text,name='xx'),
]

這裡需要註意的是當text中的url中需要傳參所以對應的text視圖函數中就需要*args,**kwargs接受參數

3.帶命名的正則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("進入text")
urlpatterns = [
    url(r'^index/', index,),
    url(r'^text/dasd/asd/(?P<a1>\d+)/sad/(?P<a2>\d+)/as/d', text,name='xx'),
]

這裡和常規帶參數的唯一不同reverse方法中是傳遞一個kwargs的鍵值對的字典

4.前端顯示反向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.單層嵌套

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中相當於嵌套了一層，且有namespance(x1,x2),所以對於這類的url的反向生成需要如下操作：

test_url = reverse('x1:txt')

2.多層嵌套

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')),
    ]

這裡雙層嵌套的url,但是內層的namespance都是空所以它會往外層找，所
以反向生成的代碼：

test_url = reverse('x1:txt')

同時當內層namespance有值時：

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代碼就是如下：

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')

所以通過上述的案例可以知道，不管url嵌套多少層，其反向生成url的規則是一樣的，遵循的規則就是namespance從外層以冒號連接至最後一層。