Django - URL Mapping

Django - URL Mapping 

Django has his own way for URL mapping and it's done by editing your project url.py file (myproject/url.py). The url.py file looks like −

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from django.conf.urls import patterns, include, url from django.contrib import admin admin.autodiscover()   urlpatterns = patterns('',    #Examples    #url(r'^$', 'myproject.view.home', name = 'home'),    #url(r'^blog/', include('blog.urls')),      url(r'^admin', include(admin.site.urls)), )

When a user makes a request for a page on your web app, Django controller takes over to look for the corresponding view via the url.py file, and then return the HTML response or a 404 not found error, if not found. In url.py, the most important thing is the "urlpatterns" tuple. It’s where you define the mapping between URLs and views. A mapping is a tuple in URL patterns like −

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from django.conf.urls import patterns, include, url from django.contrib import admin admin.autodiscover()   urlpatterns = patterns('',    #Examples    #url(r'^$', 'myproject.view.home', name = 'home'),    #url(r'^blog/', include('blog.urls')),      url(r'^admin', include(admin.site.urls)),    url(r'^hello/', 'myapp.views.hello', name = 'hello'), )

Sending Parameters to Views

how to send parameters to views. A classic sample is the article example (you want to access an article via "/articles/article_id").

"myapp/view.py"

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from django.shortcuts import render from django.http import HttpResponse   def hello(request):    return render(request, "hello.html", {})   def viewArticle(request, articleId):    text = "Displaying article Number : %s"%articleId    return HttpResponse(text)

We want to map it in myapp/url.py so we can access it via "/myapp/article/articleId", we need the following in "myapp/url.py" −

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from django.conf.urls import patterns, include, url   urlpatterns = patterns('myapp.views',    url(r'^hello/', 'hello', name = 'hello'),    url(r'^morning/', 'morning', name = 'morning'),    url(r'^article/(\d+)/', 'viewArticle', name = 'article'),)

http://127.0.0.1:8000/myapp/article/42/

output : Displaying article number : 42

Suppose we want the list of articles of a month of a year, let's add a viewArticles view. Our view.py becomes −

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from django.shortcuts import render from django.http import HttpResponse   def hello(request):    return render(request, "hello.html", {})   def viewArticle(request, articleId):    text = "Displaying article Number : %s"%articleId    return HttpResponse(text)   def viewArticle(request, month, year):    text = "Displaying articles of : %s/%s"%(year, month)    return HttpResponse(text)

The corresponding url.py file will look like −

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from django.conf.urls import patterns, include, url   urlpatterns = patterns('myapp.views',    url(r'^hello/', 'hello', name = 'hello'),    url(r'^morning/', 'morning', name = 'morning'),    url(r'^article/(\d+)/', 'viewArticle', name = 'article'),    url(r'^articles/(\d{2})/(\d{4})', 'viewArticles', name = 'articles'),)

http://127.0.0.1:8000/myapp/articles/12/2016/

Displaying articles of : 2016/12

To avoid that, it is possible to link a URL parameter to the view parameter. For that, our url.py will become −

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from django.conf.urls import patterns, include, url   urlpatterns = patterns('myapp.views',    url(r'^hello/', 'hello', name = 'hello'),    url(r'^morning/', 'morning', name = 'morning'),    url(r'^article/(\d+)/', 'viewArticle', name = 'article'),    url(r'^articles/(?P\d{2})/(?P\d{4})', 'viewArticles', name = 'articles'),)