django学习笔记(3)

Part 3: Views and templates

====> Write your first view

$ edit polls\views.py

from django.http import HttpResponse

def index(request):

    return HttpResponse("Hello, world. You're at the polls index.")

$ edit polls\urls.py

from django.conf.urls import url

from . import views

urlpatterns = [

    url(r'^$', views.index, name='index'),

]

$ edit mysite\urls.py

from django.conf.urls import include, url

from django.contrib import admin

    url(r'^polls/', include('polls.urls')),

    url(r'^admin/', include(admin.site.urls)),

====> Writing more views

# ...

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)

    # ex: /polls/

    # ex: /polls/5/

    url(r'^(?P<question_id>[0-9]+)/$', views.detail, name='detail'),

    # ex: /polls/5/results/

    url(r'^(?P<question_id>[0-9]+)/results/$', views.results, name='results'),

    # ex: /polls/5/vote/

    url(r'^(?P<question_id>[0-9]+)/vote/$', views.vote, name='vote'),

====> Write views that actually do something

from .models import Question

    latest_question_list = Question.objects.order_by('-pub_date')[:5]

    output = ', '.join([p.question_text for p in latest_question_list])

    return HttpResponse(output)

# Leave the rest of the views (detail, results, vote) unchanged

$ edit 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 %}

from django.template import RequestContext, loader

    template = loader.get_template('polls/index.html')

    context = RequestContext(request, {

        'latest_question_list': latest_question_list,

    })

    return HttpResponse(template.render(context))

====> A shortcut: render()

from django.shortcuts import render

    context = {'latest_question_list': latest_question_list}

    return render(request, 'polls/index.html', context)

====> Raising a 404 error

from django.http import Http404

    try:

        question = Question.objects.get(pk=question_id)

    except Question.DoesNotExist:

        raise Http404("Question does not exist")

    return render(request, 'polls/detail.html', {'question': question})

$ edit polls\templates\polls\detail.html

{{ question }}

====> A shortcut: get_object_or_404()

from django.shortcuts import get_object_or_404, render

    question = get_object_or_404(Question, pk=question_id)

====> Use the template system

<h1>{{ question.question_text }}</h1>

<ul>

{% for choice in question.choice_set.all %}

    <li>{{ choice.choice_text }}</li>

{% endfor %}

</ul>

====> Removing hardcoded URLs in templates

from: <li><a href="/polls/{{ question.id }}/">{{ question.question_text }}</a></li>

to:   <li><a href="{% url 'detail' question.id %}">{{ question.question_text }}</a></li>

====> Namespacing URL names

    url(r'^polls/', include('polls.urls', namespace="polls")),

from: <li><a href="{% url 'detail' question.id %}">{{ question.question_text }}</a></li>

to:   <li><a href="{% url 'polls:detail' question.id %}">{{ question.question_text }}</a></li>