Django L4 编写你的第一个Django应用

编写一个简单的表单

$ cat tasks/views.py | tail -18

def vote(request, question_id):
    p = get_object_or_404(Questions, pk=question_id)
    try:
        selected_choice = p.choice_set.get(pk=request.POST['choice'])
    except (KeyError, Choice.DoesNotExist):
        # Redisplay the question voting form.
        return render(request, 'tasks/detail.html', {
            'question': p,
            '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('tasks:results', args=(p.id,)))

$cat tasks/urls.py
#!/usr/bin/env python
#-*- coding: utf-8 -*-

__author__ = 'Ye Lin'
__date__ = '17-2-9'

from django.conf.urls import url

from . import views

urlpatterns = [
    url(r'^$' , views.index , name='index'),
    url(r'^(?P<question_id>[0-9]+)/$', views.detail, name='detail'),
    # http://127.0.0.1:20001/tasks/1/results/
    url(r'^(?P<question_id>[0-9]+)/results/$', views.results, name='results'),
    # http://127.0.0.1:20001/tasks/1/vote/
    url(r'^(?P<question_id>[0-9]+)/vote/$', views.vote, name='vote'),

]

　　

 　　由于这种情况非常普遍，Django提供了一种叫做“generic views”的系统可以方便地进行处理。

使用通用视图，代码少点

　　改良URLconf

#!/usr/bin/env python
#-*- coding: utf-8 -*-

__author__ = 'Ye Lin'
__date__ = '17-2-9'

from django.conf.urls import url

from . import views


urlpatterns = [
    url(r'^$', views.IndexView.as_view(), name='index' ),
    url(r'^(?P<pk>[0-9]+)/$', views.DetailView.as_view(), name='detail'),
    url(r'^(?P<pk>[0-9]+)/results/$', views.ResultsView.as_view(), name='results'),
    url(r'^(?P<question_id>[0-9]+)/vote/$', views.vote, name='vote'),
]

　　

改良视图

from django.shortcuts import render , get_object_or_404 , HttpResponseRedirect
from django.http import Http404
from django.http import HttpResponse
from django.core.urlresolvers import reverse
from django.views import generic
# Create your views here.

from .models import *
from django.template import RequestContext, loader



class IndexView(generic.ListView):
    template_name = 'tasks/index.html'
    context_object_name = 'latest_question_list'

    def get_queryset(self):
        """Return the last five published questions."""
        return Questions.objects.order_by('-pub_date')[:5]


class DetailView(generic.DetailView):
    model = Questions
    template_name = 'tasks/detail.html'


class ResultsView(generic.DetailView):
    model = Questions
    template_name = 'tasks/results.html'


def vote(request, question_id):
    p = get_object_or_404(Questions, pk=question_id)
    try:
        selected_choice = p.choice_set.get(pk=request.POST['choice'])
    except (KeyError, Choice.DoesNotExist):
        # Redisplay the question voting form.
        return render(request, 'tasks/detail.html', {
            'question': p,
            '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('tasks:results', args=(p.id,)))