Django(part4)

一个简单的form表单:

#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>

forloop.counter:表示for循环执行的次数
action="{% url 'polls:vote' question.id %}":指定处理post 数据的url
{% csrf_token %}:用于防止csrf攻击的tag,所有post的form都应该使用

处理post的代码:

#polls/urls.py

url(r'^(?P<question_id>\d+)/vote/$', views.vote, name='vote'),

#polls/views.py

from django.shortcuts import get_object_or_404, render

from django.http import HttpResponseRedirect, HttpResponse

from django.core.urlresolvers import reverse

from polls.models import Choice, Question

# ...

def vote(request, question_id):

    p = get_object_or_404(Question, 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, 'polls/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('polls:results', args=(p.id,)))

# polls/view.py

from  django.shortcuts import get_object_or_404, render

def results(request, question_id):

    question = get_object_or_404(Question, pk=question_id)

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

request.POST:用于获取表单的值，同样的属性还有request.GET
request.POST[‘choice’]:choice是key值，不存在时引发KeyError exception
HttpResponseRedirect():参数是一个重定向的url\
reverse():返回一个url，通过使用url name避免hardcode

Generic view:

from django.shortcuts import get_object_or_404, render

from django.http import HttpResponseRedirect

from django.core.urlresolvers import reverse

from django.views import generic

from polls.models import Choice, Question

class IndexView(generic.ListView):

    template_name = 'polls/index.html'

    context_object_name = 'latest_question_list'

    def get_queryset(self):

        """Return the last five published questions."""

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

class DetailView(generic.DetailView):

    model = Question

#template_name 告诉django自动生成的template的name

#如果不指定默认为<app name>/<model name>_detail.html

    template_name = 'polls/detail.html'

#polls/urls.py

#注意必须用<pk>指定匹配的组名

urlpatterns = patterns('',

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

    url(r'^(?P<pk>\d+)/$', views.DetailView.as_view(), name='detail'),

)

静态文件:django的STATICFILES_FINDERS setting保存了一系列finder,这些finder知道如何去查找静态文件。如AppDirectoriesFinder就会在INSTALLED_APPS包含的app的子目录下查找static目录。通常用如下存放静态文件，polls/static/polls/style.css或者polls/static/polls/images/background.gif，这样AppDirectoriesFinder可以找到,路径中第二个polls相当于静态文件的名字空间
```
#polls/templates/polls/index.html

{% load staticfiles %}

<link rel="stylesheet" type="text/css" href="{% static 'polls/style.css' %}" />
```
How to packaging your app:参考https://docs.djangoproject.com/en/1.7/intro/reusable-apps/
```
 
```

巴特西

Django(part4)

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