如何向django QuerySet的每个条目添加一些上下文 [英] How to add some context to each entry of a django QuerySet

问题描述

我使用Django 1.8.4与Python 3.4

我有一个比赛模型，定义一个方法，如果禁止订阅，则返回一个字符串。 >

  class Tournament（models.Model）：
 name = models.CharField（max_length = 200，null = True，blank = True ）
 subscriptions = models.ManyToManyField（'ap_users.Profile'）
 is_subscription_open = models.BooleanField（default = True）
＃... 
 
 def why_subscription_impossible自我请求）：
如果没有request.user.profile.is_profile_complete（）：
返回'您的个人资料不完整'
 elif不self.is_subscription_open：
返回'订阅被关闭'
 elif< another_condition> ;: 
 return'另一个错误消息'
 
返回无
  

我想使用一般的ListView显示锦标赛的列表，我想使用修改显示方式的方法：

 < table class =table> 
< thead> 
< td> Tournament< / td> 
< td>订阅< / td> 
< / thead> 
 {％in tournament_list％} 
< tr> 
< td> {{tournament.name}}< / td> 
< td> 
 {％if tournament.why_subscription_impossible％} 
 {{tournament.why_subscription_impossible}} 
 {％else％} 
< a href ={％url'ap_tournament：subscribe' tournament.id％}>订阅< / a> 
 {％endif％} 
< / td> 
< / tr> 
 {％endfor％} 
< / table> 
  

该视图是继承自 generic.ListView 。

  class IndexView（generic.ListView）：
 template_name ='ap_tournament / index.html '
 
 def get_queryset（self）：
 return Tournament.objects.all（）
  

显示的解决方案不起作用，因为我需要传递当前请求，以获取有关日志用户的信息。所以我试图将方法的结果添加到视图中的上下文

  class IndexView（generic.ListView）：
 template_name ='ap_tournament / index.html'
 
 def get_queryset（self）：
 return Tournament.objects.all（）
 
 def get_context_data（self， ** kwargs）
 context = super（IndexView，self）.get_context_data（** kwargs）
 
 additional_ctx_info = [] 
为self.get_queryset（）中的比赛：
 additional_ctx_info.append（{
'reason_to_not_subscribe'：tournament.why_subscription_impossible（self.request）
}）
 
上下文['subscr_info'] = additional_ctx_info 
返回上下文
  

显然，这也不行。我不知道如何使用n在tournament_list中的当前索引访问 subscr_info [n] 。我知道 forloop.counter0 来获取索引，但是我不能在模板中使用它（或者我不知道如何）。我试过：

• {{subscr_info.forloop.counter0.reason_to_not_subscribe}} / li>
  
• {{subscr_info。{{forloop.counter0}}。reason_to_not_subscribe}}

我还尝试在get_queryset（）视图方法中注释QuerySet，并阅读有关aggregate（）的信息，但我觉得仅在数据库支持的操作（AVG，COUNT，MAX，等等）。

我也觉得使用过滤器或模板标签在我的情况下不起作用，因为我需要使用方法的结果在code>如果标签。

有没有更好的解决方案或完全不同的方法来实现我想要的？

解决方案

在您看来，您还可以：

  tournaments = self.get_queryset（）
在比赛中的比赛：
 tournament.reason_to_not_subscribe = tournament.why_subscription_impossible（self.request）
  

然后在上下文中添加 tournaments 。

I use Django 1.8.4 with Python 3.4

I have a model for tournaments that defines a method which returns a string if a subscription is forbidden.

class Tournament(models.Model):
    name = models.CharField(max_length=200, null=True, blank=True)
    subscriptions = models.ManyToManyField('ap_users.Profile')
    is_subscription_open = models.BooleanField(default=True)
    # ...

    def why_subscription_impossible(self, request):
        if not request.user.profile.is_profile_complete():
            return 'Your profile is not complete'
        elif not self.is_subscription_open:
            return 'Subscriptions are closed'
        elif <another_condition>:
            return 'Another error message'

        return None

I want to display the list of tournaments, using a generic ListView, and I want to use the result of the method to modify the way it is displayed:

<table class="table">
    <thead>
        <td>Tournament</td>
        <td>Subscription</td>
    </thead>
    {% for tournament in tournament_list %}
        <tr>
            <td>{{ tournament.name }}</td>
            <td>
                {% if tournament.why_subscription_impossible %}
                    {{ tournament.why_subscription_impossible }}
                {% else %}
                    <a href="{% url 'ap_tournament:subscribe' tournament.id %}">Subscribe</a>
                {% endif %}
            </td>
        </tr>
    {% endfor %}
</table>

The view is a class based generic view inherited from generic.ListView.

class IndexView(generic.ListView):
    template_name = 'ap_tournament/index.html'

    def get_queryset(self):
        return Tournament.objects.all()

The shown solution doesn't work, because I need to pass the current request, to get information about logged user. So I tried to add the result of the method to a context in the view

class IndexView(generic.ListView):
    template_name = 'ap_tournament/index.html'

    def get_queryset(self):
        return Tournament.objects.all()

    def get_context_data(self, **kwargs):
        context = super(IndexView, self).get_context_data(**kwargs)

        additional_ctx_info = []
        for tournament in self.get_queryset():
            additional_ctx_info.append({
                'reason_to_not_subscribe': tournament.why_subscription_impossible(self.request)
            })

        context['subscr_info'] = additional_ctx_info
        return context

Obviously, this doesn't work too. I don't know how to access to the subscr_info[n] with n the current index in the tournament_list. I know the forloop.counter0 to get the index, but I can't use it in the template (or I don't know how). I tried :

• {{ subscr_info.forloop.counter0.reason_to_not_subscribe }}
• {{ subscr_info.{{forloop.counter0}}.reason_to_not_subscribe }}

I also tried to annotate the QuerySet in get_queryset() view method and read about aggregate(), but I feel that works only with operations supported by the database (AVG, COUNT, MAX, etc.).

I also feels that using a filter or a template tag will not work in my case since I need to use the result of the method in a if tag.

Is there a better solution or a completely diffferent method to achieve what I want ?

解决方案

In your view, you could also do:

tournaments = self.get_queryset()
for tournament in tournaments:
    tournament.reason_to_not_subscribe = tournament.why_subscription_impossible(self.request)

Then add tournaments to the context.

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