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1. Let’s add a few more views to polls/views.py. These views are slightly different, because they take an argument:

   Code Block
   title polls/views.py
   def detail(request, question_id): return HttpResponse("You're looking at question %s." % question_id) def results(request, question_id): response = "You're looking at the results of question %s." return HttpResponse(response % question_id) def vote(request, question_id): return HttpResponse("You're voting on question %s." % question_id)

   Wire these new views into the polls.urls module by adding the following path() calls:

   Code Block
   title polls/urls.py
   from django.urls import path from . import views urlpatterns = [ # ex: /polls/ path('', views.index, name='index'), # ex: /polls/5/ path('<int:question_id>/', views.detail, name='detail'), # ex: /polls/5/results/ path('<int:question_id>/results/', views.results, name='results'), # ex: /polls/5/vote/ path('<int:question_id>/vote/', views.vote, name='vote'), ]

   Take a look in your browser, at “/polls/34/”. It’ll run the detail() method and display whatever ID you provide in the URL. Try “/polls/34/results/” and “/polls/34/vote/” too – these will display the placeholder results and voting pages.
    

2. Here’s one stab at a new index() view, which displays the latest 5 poll questions in the system, separated by commas, according to publication date:

   Code Block
   title polls/urls.py
   def index(request): latest_question_list = Question.objects.order_by('-pub_date')[:5] output = ', '.join([q.question_text for q in latest_question_list]) return HttpResponse(output)

   There’s a problem here, though: the page’s design is hard-coded in the view. If you want to change the way the page looks, you’ll have to edit this Python code. So let’s use Django’s template system to separate the design from Python by creating a template that the view can use.
   
   

3. Create a directory called templates in your polls directory. Django will look for templates in there.
   Within the templates directory you have just created, create another directory called polls, and within that create a file called index.html. In other words, your template should be at polls/templates/polls/index.html. Because of how the app_directories template loader works as described above, you can refer to this template within Django simply as polls/index.html.

   Code Block
   title polls/templates/polls/index.html
   {% if latest_question_list %} <ul> {% for question in latest_question_list %} <li><a href="/polls/{{ question.id }}/">{{ question.question_text }}</a></li> {% endfor %} </ul> {% else %} <p>No polls are available.</p> {% endif %}

   The problem above is the URL is hardcoded - it may not critical, but let us add more flexibility by the defined argument in the path() function in  the polls.urls module, so you can remove a reliance on specific URL paths defined in your url configurations by using the {% url %} template tag like below:

   Code Block
   {% if latest_question_list %} <ul> {% for question in latest_question_list %} <li><a href="{% url 'detail' question.id %}">{{ question.question_text }}</a></li> {% endfor %} </ul> {% else %} <p>No polls are available.</p> {% endif %}

   
   Now let’s update our index view in polls/views.py to use the template:

   Code Block
   title polls/views.py
   from django.http import HttpResponse from django.template import loader from .models import Question . . . def index(request): latest_question_list = Question.objects.order_by('-pub_date')[:5] context = {'latest_question_list': latest_question_list} return HttpResponse(request, 'polls/index.html', context)

   
   

4. Raising a 404 error
   Now, let’s tackle the question detail view – the page that displays the question text for a given poll. Here’s the view:

   Code Block
   title polls/views.py
   from django.shortcuts import get_object_or_404, render from .models import Question . . . def detail(request, question_id): try: question = Question.objects.get(get_object_or_404(Question, pk=question_id) except Question.DoesNotExist: raise Http404("Question does not exist") return render(request, 'polls/detail.html', {'question': question})

   And you will need to have detail.html on template

   Code Block
   title polls/templates/polls/detail.html
   <h1>{{ question.question_text }}</h1> <ul> {% for choice in question.choice_set.all %} <li>{{ choice.choice_text }}</li> {% endfor %} </ul>

   
   

5. Removing hardcoded URLs in templates by app_name as namespace

   The tutorial project has just one app, polls. In real Django projects, there might be five, ten, twenty apps or more. How does Django differentiate the URL names between them? For example, the polls app has a detail view, and so might an app on the same project that is for a blog. How does one make it so that Django knows which app view to create for a url when using the {% url %} template tag?

   The answer is to add namespaces to your URLconf. In the polls/urls.py file, go ahead and add an app_name to set the application namespace:

   Code Block
   language py title polls/urls.py
   from django.urls import path from . import views app_name = 'polls' urlpatterns = [ path('', views.index, name='index'), path('<int:question_id>/', views.detail, name='detail'), path('<int:question_id>/results/', views.results, name='results'), path('<int:question_id>/vote/', views.vote, name='vote'), ]

   
   Now change your polls/index.html template from:

   Code Block
   title polls/templates/polls/index.html
   <li><a href="{% url 'detail' question.id %}">{{ question.question_text }}</a></li>

   to point at the namespaced detail view:

   Code Block
   title polls/templates/polls/index.html
   <li><a href="{% url 'polls:detail' question.id %}">{{ question.question_text }}</a></li>

   
   

6. Write a simple form
   Let’s update our poll detail template (“polls/detail.html”) from the last tutorial, so that the template contains an HTML <form> element:

   Code Block
   language py title polls/templates/polls/detail.html
   <h1>{{ question.question_text }}</h1> {% if error_message %}<p><strong>{{ error_message }}</strong></p>{% endif %} <form action="{% url 'polls:vote' question.id %}" method="post"> {% csrf_token %} {% for choice in question.choice_set.all %} <input type="radio" name="choice" id="choice{{ forloop.counter }}" value="{{ choice.id }}"> <label for="choice{{ forloop.counter }}">{{ choice.choice_text }}</label><br> {% endfor %} <input type="submit" value="Vote"> </form>

    Note that we’re creating a POST form (which can have the effect of modifying data), we need to worry about Cross Site Request Forgeries. Thankfully, you don’t have to worry too hard, because Django comes with a very easy-to-use system for protecting against it. In short, all POST forms that are targeted at internal URLs should use the {%csrf_token %} template tag
   
   

7. We also created a dummy implementation of the vote() function. Let’s create a real version. Add the following to polls/views.py:

   Code Block
   language py title polls/views.py
   from django.http import HttpResponse, HttpResponseRedirect from django.shortcuts import get_object_or_404, render from django.urls import reverse from .models import Choice, Question . . . def vote(request, question_id): question = get_object_or_404(Question, pk=question_id) try: selected_choice = question.choice_set.get(pk=request.POST['choice']) except (KeyError, Choice.DoesNotExist): # Redisplay the question voting form. return render(request, 'polls/detail.html', { 'question': question, 'error_message': "You didn't select a choice.", }) else: selected_choice.votes += 1 selected_choice.save() # Always return an HttpResponseRedirect after successfully dealing # with POST data. This prevents data from being posted twice if a # user hits the Back button. return HttpResponseRedirect(reverse('polls:results', args=(question.id,)))