Django根据条件更改模板上的<a>标记

Question

我有可以选择保存它的帖子。视图工作正常，但我看不到按钮中的变化。我希望当它没有被用户保存时，按钮上写着“保存帖子”，当它已经保存时，按钮应该说“取消保存”。最后这部分我有问题了。这是代码的一部分。

views.py

def post(request):
    posts = Post.objects.all().order_by("-date_created")
    return render(request, "post/food-feed.html", {"posts": posts})

def save_post(request, pk):
    post = get_object_or_404(Post, id=pk)
    if post.favorite_posts.filter(id=request.user.id).exists():
        post.favorite_posts.remove(request.user)
    else:
        post.favorite_posts.add(request.user)
    return HttpResponseRedirect(request.META["HTTP_REFERER"])

模板

<a href="{% url 'save-post' post.id %}" class="btn btn-primary float-start">Save post</a> 

urls.py

path("post/<int:pk>/save", views.save_post, name="save-post")

forms.py

class UserSignupForm(UserCreationForm):
    email = forms.EmailField()

    class Meta:
        model = User
        fields = ["username", "email", "password1", "password2"]

    def clean_username(self):
        username = self.cleaned_data["username"].lower()

        if not re.match(r"^[A-Za-z0-9_]+$", username):
            raise forms.ValidationError(
                "Sorry, your username must only contain letters, numbers and underscores."
            )

        elif (
            User.objects.exclude(pk=self.instance.pk).filter(username=username).exists()
        ):
            raise forms.ValidationError(f"Username {username} is already in use.")
        else:
            return username

models.py

class Post(models.Model):
    author = models.ForeignKey(User, on_delete=models.CASCADE)
    title = models.CharField(max_length=80)
    slug = models.SlugField(max_length=250, null=True, blank=True)
    post_description = models.TextField(max_length=140, null=True, blank=True)
    date_created = models.DateTimeField(default=timezone.now)
    date_updated = models.DateTimeField(auto_now=True)
    main_image = models.ImageField(upload_to="post_pics")
    is_recipe = models.BooleanField()
    ingredients = models.TextField(blank=True, null=True)
    recipe_description = models.TextField(blank=True, null=True)
    cooking_time = models.CharField(max_length=20, blank=True, null=True)
    likes = models.ManyToManyField(User, related_name="post_likes")
    loves = models.ManyToManyField(User, related_name="post_loves")
    drooling_faces = models.ManyToManyField(User, related_name="post_drooling_faces")
    favorite_posts = models.ManyToManyField(
        User, related_name="favorite_posts", default=None, blank=True
    )

    def clean(self, *args, **kwargs):
        if (
            (self.is_recipe and self.ingredients == None)
            or (self.is_recipe and self.ingredients == None)
            or (self.is_recipe and self.recipe_description == None)
            or (self.is_recipe and self.cooking_time == None)
        ):
            raise ValidationError("You need to complete the recipe fields!")
        if not self.slug:
            slug_title = slugify(self.title)
            slug_date = slugify(self.date_created)
            self.slug = f"{slug_title}-{slug_date}"
        super().clean(*args, **kwargs)

    class Meta:
        ordering = ("-date_created",)

    def save(self, *args, **kwargs):
        self.full_clean()
        return super().save(*args, **kwargs)

    def __str__(self) -> str:
        return self.title

    def get_absolute_url(self):
        return reverse("post-detail", kwargs={"slug": self.slug})

    def like_count(self):
        return self.likes.count()

    def love_count(self):
        return self.loves.count()

    def droolingface_count(self):
        return self.drooling_faces.count()

每一篇文章都显示在用户图片、用户名、日期、照片、标题、喜欢、描述和保存按钮中，我需要添加哪些内容才能使语句工作呢？

Answer 1

您可以使用queryset指定或自定义筛选标记。我不认识你的模特。但是您可以在post视图中注释类似于以下内容的is_favorite：

from django.db.models import Exists, OuterRef

Post.objects.annotate(
    is_favorite=Exists(
        Favorite.objects.filter(user=user, product_id=OuterRef('pk'))
    )
)

在模板中：

{% if post.is_favorite %}
save
{% else %}
unsave
{% endif %}