Django模型中实现用户特定状态（如点赞）的策略：使用中间关联模型

from django.db import models
from django.contrib.auth import get_user_model

# 获取当前项目使用的User模型
User = get_user_model()

class Post(models.Model):
    title = models.CharField(max_length=200)
    content = models.TextField()
    author = models.ForeignKey(User, on_delete=models.CASCADE, related_name='posts')
    # ... 其他字段

    def __str__(self):
        return self.title

class PostLike(models.Model):
    """
    表示用户对文章的点赞记录
    """
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    post = models.ForeignKey(Post, on_delete=models.CASCADE, related_name='likes')
    # 可以添加更多字段，例如点赞时间
    # liked_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        # 确保每个用户只能对同一篇文章点赞一次
        unique_together = ('user', 'post')
        verbose_name = '文章点赞'
        verbose_name_plural = '文章点赞'

    def __str__(self):
        return f"{self.user.username} liked {self.post.title}"

from django.shortcuts import get_object_or_404
from .models import Post, PostLike

def like_post(request, post_id):
    post = get_object_or_404(Post, id=post_id)
    # 假设 request.user 是当前已登录的用户
    if request.user.is_authenticated:
        # 尝试创建点赞记录
        # 如果已存在，unique_together 会阻止重复创建，并抛出IntegrityError
        # 更好的做法是先检查是否存在
        if not PostLike.objects.filter(user=request.user, post=post).exists():
            PostLike.objects.create(user=request.user, post=post)
            return "点赞成功"
        else:
            return "您已点赞过该文章"
    return "请登录后点赞"

def check_if_liked(request, post_id):
    post = get_object_or_404(Post, id=post_id)
    if request.user.is_authenticated:
        is_liked = PostLike.objects.filter(user=request.user, post=post).exists()
        return f"用户{'已' if is_liked else '未'}点赞该文章"
    return "请登录"

def unlike_post(request, post_id):
    post = get_object_or_404(Post, id=post_id)
    if request.user.is_authenticated:
        like_instance = PostLike.objects.filter(user=request.user, post=post)
        if like_instance.exists():
            like_instance.delete()
            return "取消点赞成功"
        else:
            return "您尚未点赞该文章"
    return "请登录"

def get_post_like_count(post_id):
    post = get_object_or_404(Post, id=post_id)
    return post.likes.count() # 使用 related_name='likes'

def get_user_liked_posts(user):
    # 通过 PostLike 反向查询，然后获取对应的 Post 对象
    return Post.objects.filter(likes__user=user)