Django 赞成/反对方法

Question

我正在做一个小应用，让用户可以对某些项目进行投票，选择赞成或反对。我在用Django（我还是新手！）。

我想知道，给用户展示赞成投票的链接，最好的方式是什么？是用链接、按钮还是其他什么方式？

我之前在用php和其他框架做过类似的事情，但不太确定能不能用同样的方法。我的想法是，应该有一个方法来处理赞成和反对投票，然后给用户显示一个可以点击的链接。当他们点击后，执行这个方法并刷新页面吗？

Answer 1

无论你做什么，一定要确保使用POST方式提交，而不是GET方式；因为GET请求绝对不应该修改数据库中的信息。

Answer 2

这是我解决问题的核心思路。我使用图片配合jQuery和AJAX来处理点击事件。这个想法受到了某个网站的很大影响。虽然有些地方还需要改进（比如客户端的错误处理，还有很多代码可能需要重构），但希望这些代码对你有帮助。

下面是HTML部分：

        <div class="vote-buttons">
        {% ifequal thisUserUpVote 0 %}
        <img class="vote-up" src = "images/vote-up-off.png" title="Vote this thread UP. (click again to undo)" />
        {% else %}
        <img class="vote-up selected" src = "images/vote-up-on.png" title="Vote this thread UP. (click again to undo)" />
        {% endifequal %}
        {% ifequal thisUserDownVote 0 %}
        <img class="vote-down" src = "images/vote-down-off.png" title="Vote this thread DOWN if it is innapropriate or incorrect. (click again to undo)" />
        {% else %}
        <img class="vote-down selected" src = "images/vote-down-on.png" title="Vote this thread DOWN if it is innapropriate or incorrect. (click again to undo)" />
        {% endifequal %}
        </div> <!-- .votebuttons -->

接下来是jQuery部分：

$(document).ready(function() {

    $('div.vote-buttons img.vote-up').click(function() {

        var id = {{ thread.id }};
        var vote_type = 'up';

        if ($(this).hasClass('selected')) {
            var vote_action = 'recall-vote'
            $.post('/ajax/thread/vote', {id:id, type:vote_type, action:vote_action}, function(response) {
                if (isInt(response)) {
                    $('img.vote-up').removeAttr('src')
                        .attr('src', 'images/vote-up-off.png')
                        .removeClass('selected');
                    $('div.vote-tally span.num').html(response);
                }
            });
        } else {

            var vote_action = 'vote'
            $.post('/ajax/thread/vote', {id:id, type:vote_type, action:vote_action}, function(response) {
                if (isInt(response)) {
                    $('img.vote-up').removeAttr('src')
                        .attr('src', 'images/vote-up-on.png')
                        .addClass('selected');
                    $('div.vote-tally span.num').html(response);
                }
            });
        }
    });

然后是处理AJAX请求的Django视图：

def vote(request):
   thread_id = int(request.POST.get('id'))
   vote_type = request.POST.get('type')
   vote_action = request.POST.get('action')

   thread = get_object_or_404(Thread, pk=thread_id)

   thisUserUpVote = thread.userUpVotes.filter(id = request.user.id).count()
   thisUserDownVote = thread.userDownVotes.filter(id = request.user.id).count()

   if (vote_action == 'vote'):
      if (thisUserUpVote == 0) and (thisUserDownVote == 0):
         if (vote_type == 'up'):
            thread.userUpVotes.add(request.user)
         elif (vote_type == 'down'):
            thread.userDownVotes.add(request.user)
         else:
            return HttpResponse('error-unknown vote type')
      else:
         return HttpResponse('error - already voted', thisUserUpVote, thisUserDownVote)
   elif (vote_action == 'recall-vote'):
      if (vote_type == 'up') and (thisUserUpVote == 1):
         thread.userUpVotes.remove(request.user)
      elif (vote_type == 'down') and (thisUserDownVote ==1):
         thread.userDownVotes.remove(request.user)
      else:
         return HttpResponse('error - unknown vote type or no vote to recall')
   else:
      return HttpResponse('error - bad action')


   num_votes = thread.userUpVotes.count() - thread.userDownVotes.count()

   return HttpResponse(num_votes)

最后是线程模型中相关的部分：

class Thread(models.Model):
    # ...
    userUpVotes = models.ManyToManyField(User, blank=True, related_name='threadUpVotes')
    userDownVotes = models.ManyToManyField(User, blank=True, related_name='threadDownVotes')

Answer 3

直接插上就能用：

Reddit风格投票
使用django-voting为任何模型实现Reddit风格的投票
http://code.google.com/p/django-voting/wiki/RedditStyleVoting