检查用户是否在 Many2Many 字段中

Question

我有以下模型，其中包含 m2m 字段，登录的用户可以对出版物表现出兴趣：

models.py

from django.db import models

class Publication:
  title = models.CharField(max_lenth=512)
  users_interested = models.ManyToManyField(User)

views.py

from django.shortcuts import render
from django.views import View
from .models import Publication

class listPublicationView(View):
  def get(self, request, *args, **kwargs):

    publications = Publication.objects.all()

    return render(request, "base.html", {'publications': publications})

现在，当登录用户已经对出版物感兴趣时，我尝试在模板中生成“我已经感兴趣”：

base.html

{% for publication in publications %}

  {{publication.title}}

  {% if currently logged in User is interested in publication (check users_interested) %}
      i am already interested
  {% endif %}

{% endfor %}

我在想这样的事情：

{% if user.id in publication.users_interested__id %}

Answer 1

试试这样：

{% if request.user in publication.users_interested.all %}

• request.user 属性保存当前登录用户
• 然后您将in 运算符与publications.users_interested.all() 一起使用（请注意，模板中.all() 上没有括号

Answer 2

这似乎是一个不错的解决方案：

models.py

from django.db import models

class Publication:
  title = models.CharField(max_lenth=512)

  #added a reverse accessor
  users_interested = models.ManyToManyField(User, related_name='users_interested')

view.py

from django.shortcuts import render
from django.views import View
from .models import Publication

class listPublicationView(View):
  def get(self, request, *args, **kwargs):

    publications = Publication.objects.all()

    # create a set of group IDs that this user is a part of
    current_user = request.user
    user_publication_set = set(current_user.users_interested.values_list('id', flat=True))

    #pass set to template
    return render(request, "base.html", {'publications': publications, 'user_publication_set': user_publication_set})

base.html

{% for publication in publications %}

  {{publication.title}}

  {% if publication.id in user_publication_set %}
      i am already interested
  {% endif %}

{% endfor %}

在Django: check for value in ManyToMany field in template找到这个解决方案