django URLconf學習

django 1.4.5 documentation

    The view layer -->The basics
一、
patterns語法格式：

patterns = pattern('prefix',     //prefix一般爲空
    url()
)

url語法格式：

patterns = pattern('prefix',
    url(regular expression, view function [, optional dictionary[, name]])
)

optional dictionary是字典形式參數
optional name是named url pattern
二、語法示例：

urlpatterns = pattern('',
    (r'^articles/2003/$', 'news.views.special_case_2003'),
    (r'^articles/(\d{4})/$', 'news.views.year_archive'),
    (r'^articles/(\d{4})/(\d{2})/$', 'news.views.month_archive'),
    (r'^articles/(\d{4)/(\d{2})/(\d+)/$', 'news.views.article_detail'),
)

1、括號內的參數在傳遞給view視圖函數時，都是按位置進行傳遞
2、url請求/articles/2005/03/ 會被第三條記錄匹配，Django會調用news.views.month_archive(request, '2005', '03')函數來處理URL請求
3、第一條和第二條記錄都能匹配url請求/articles/2003/ , 但是django會使用第一條記錄來匹配，因爲urlpattern是按順序進行匹配，只要匹配到就忽略後面的記錄。這種形式不是很好，後面會介紹在views視圖函數中使用默認參數來處理這種特殊情況
三、命名組：
命名組語法格式： (?P<name>pattern)
其中，name是分組的名稱，pattern是用於匹配的正則表達式
urls.py：

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

urlpatterns = urlpattern('',
    (r'^articles/2003/$', 'news.views.special_case_2003'),
    (r'^articles/(?P<year>\d{4})/$', 'news.views.year_archive'),
    (r'^articles/(?P<year>\d{4})/(?P<month>\d{2})/$', 'news.views.month_archive'),
    (r'^articles/(?P<year>\d{4})/(?P<month>\d{2})/(?P<day>\d{2})/$', 'news.views.article_detail'),
)

1、django會調用news.views.month_archive(request, year='2005', month='03')來處理URL請求：/articles/2005/03/ ，這種形式比按位置傳遞可讀性更強一些，也不容易出錯
四、urlpattern匹配URL請求時捕獲的參數，都是以python字符串的形式傳遞給view視圖函數，不管參數是以什麼形式被捕獲的： 

(r'^articles/(?P<year>\d{4})/$', 'news.views.year_archive'),

儘管urlpattern在匹配時，\d{4}只匹配數字，但是當它把捕獲到的年份數字傳遞給view視圖函數時，是以字符串形式傳遞的。  

  五、爲視圖函數指定默認參數：  

＃URLconf
urlpatterns = pattern('',
    (r'^blog/$', 'blog.views.page'),
    (r'^blog/page(?P<num>\d+)/$', 'blog.views.page'),
)

# View (in blog/views.py)
def page(request, num="1"):
    #Output the appropriate page of blog entries, according to num.

上述示例，所有的請求都使用blog.views.page視圖函數來處理URL請求；但當URL請求僅包括 /blog/ 時（特殊情況），被第一條記錄匹配，視圖函數page在處理該請求時，自動使用默認參數num的值1，具體形式由函數體定義。
  六、簡化urlpattern書寫：
1、The view prefix：

urlpatterns = patterns('news.views',     //把前綴news.views添加到這裏，避免在每一條記錄中重複書寫
    (r'^articles/(\d{4})/$', 'year_archive'),
    (r'^articles/(\d{4})/(\d{2})/$', 'month_archive'),
    (r'^articles/(\d{4})/(\d{2})/(\d+)/$', 'article_detail'),
)

  2、Including other URLconfs：

urlpatterns = patterns('',
    # ... snip ...
    (r'^comments/', include('django.contrib.comments.urls')),
    (r'^community/', include('django_website.aggregator.urls')),
    (r'^contact/', include('django_website.contact.urls')),
    (r'^r/', include('django.conf.urls.shortcut')),
    # ... snip ...
)

使用include時，正則表達式不能使用$，因爲在django執行時include時，是把include的url追加到後面

另一種形式：

from django.conf.urls import patterns, url, include
extra_patterns = patterns('',
    url(r'^reports/(?P<id>\d+)/$', 'credit.views.report', name='credit-reports'),
    url(r'^charge/$', 'credit.views.charge', name='credit-charge'),
)

urlpatterns = patterns('',
    url(r'^$', 'apps.main.views.homepage', name='site-homepage'),
    (r'^help/', include('apps.help.urls')),
    (r'^credit/', include(extra_patterns)),
)

七、傳遞額外參數到視圖函數：

urlpatterns = patterns('blog.views',
    (r'^blog/(?P<year>\d{4})/$', 'year_archive', {'foo': 'bar'}),
)

1、額外參數都是字典形式
2、如果字典參數的key與命名組名稱重名，則參數在傳遞給view視圖函數時，字典參數會覆蓋urlpattern捕獲的參數。如：

urlpatterns = patterns('blog.views',
    (r'^blog/(?P<year>\d{4})/$', 'year_archive', {'year': '000'}),
)

view視圖函數在處理URL請求/blog/2013/，使用的參數不是2013，而是000，儘管urlpattern捕獲的參數是2013。  

八、傳遞額外參數到include()：

# main.py
urlpatterns = patterns('',
    (r'^blog/', include('inner'), {'blogid': 3}),
)

# inner.py
urlpatterns = patterns('',
    (r'^archive/$', 'mysite.views.archive'),
    (r'^about/$', 'mysite.views.about'),
)

相當於：

# main.py
urlpatterns = patterns('',
    (r'^blog/', include('inner')),
)

# inner.py
urlpatterns = patterns('',
    (r'^archive/$', 'mysite.views.archive', {'blogid': 3}),
    (r'^about/$', 'mysite.views.about', {'blogid': 3}),
)

1、額外參數都是字典形式
2、傳遞給include()的額外參數，將傳遞到include裏的每一條記錄，不管該處理該記錄的視圖函數是否能正確接受相應的參數

九、Naming URL patterns：

urlpatterns = patterns('',
    url(r'^archive/(\d{4})/$', archive, name="full-archive"),
    url(r'^archive-summary/(\d{4})/$', archive, {'summary': True}, "arch-summary"),
)

使用：
{% url arch-summary 1945 %}
{% url full-archive 2007 %}
當多條記錄都使用同一個視圖函數處理時，使用named url來區分不同的記錄