如何在Python Flask中实现类似按钮的功能? [英] How do i implement a like button function to posts in Python Flask?

问题描述

因此，我试图在我的代码中添加一个喜欢按钮的功能，该功能允许用户喜欢特定帖子.点赞次数将链接到已登录的用户，并显示点赞次数.实施前端不会很困难，但是后端存在问题.

So i am trying to add to add a like button feature to my code that allows users to like specific posts. The likes will be linked to a logged in user and the number of likes will be shown. Implementing the front end wont be difficult but i am having a problem with the back end.

我在此使用此信息作为指导而是使用关注者系统

这是我到目前为止所拥有的?

This is what I have so far?

我在models.py中为喜欢创建了一个表:

I have created a table for likes in models.py :

likers = db.Table('likers',
    db.Column('liker_id', db.Integer, db.ForeignKey('post.id')),
    db.Column('liked_id', db.Integer, db.ForeignKey('post.id'))
)

在我的用户类的Models.py中:

In my Models.py for my user class:

class User(db.Model, UserMixin):
#Code 
liked = db.relationship(
    'User', secondary=likers,
    primaryjoin=(likers.c.liker_id == id),
    secondaryjoin=(likers.c.liked_id == id),
    backref = db.backref('likers', lazy='dynamic'), lazy='dynamic')
def like(self, post):
    if not self.is_liking(post):
        self.liked.append(post)

def unlike(self, post):
    if self.is_liking(post):
        self.liked.remove(post)

def is_liking(self, post):
    return self.liked.filter(
        likers.c.liked_id == post.id).count() > 0

在routes.py中-对于我的用户蓝图，我有:

in my routes.py- for my users blueprint I have:

@users.route("/like/<int:post_id>")
@login_required
def like(post_id):
 post = Post.query.get_or_404(post_id)
 current_user.like(post)
 db.session.commit()
 flash('Post has been liked')
 return redirect(url_for('posts.post', post_id=post.id))

@users.route("/unlike/<int:post_id>")
@login_required
def unlike(post_id):
 post = Post.query.get_or_404(post_id)
 current_user.unlike(post)
 db.session.commit()
 flash('Post has been unliked')
 return redirect(url_for('posts.post', post_id=post.id))    

我在做什么错?我不断收到诸如:

What am i doing wrong? I keep getting errors such as :

builtins.KeyError
KeyError: 'likers'

我已经完成了一个评论部分，我知道喜欢的人会比评论更贴切，但是我正在努力实现它.我是不熟悉Flask的人，我尝试使用这些文档，但找不到任何可帮助我的东西...

I have done a comment section annd i know the relatioship for the likes will be simialr to the comments but i am struggling to implement it. I am relatively new to flask and i have tried using the documentations but haven't found anything to help me...

这是我最后的希望.

推荐答案

class User(UserMixin, db.Model):
    # Code
    liked = db.relationship(
        'PostLike',
        foreign_keys='PostLike.user_id',
        backref='user', lazy='dynamic')

    def like_post(self, post):
        if not self.has_liked_post(post):
            like = PostLike(user_id=self.id, post_id=post.id)
            db.session.add(like)

    def unlike_post(self, post):
        if self.has_liked_post(post):
            PostLike.query.filter_by(
                user_id=self.id,
                post_id=post.id).delete()

    def has_liked_post(self, post):
        return PostLike.query.filter(
            PostLike.user_id == self.id,
            PostLike.post_id == post.id).count() > 0


class PostLike(db.Model):
    __tablename__ = 'post_like'
    id = db.Column(db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'))
    post_id = db.Column(db.Integer, db.ForeignKey('post.id'))


@app.route('/like/<int:post_id>/<action>')
@login_required
def like_action(post_id, action):
    post = Post.query.filter_by(id=post_id).first_or_404()
    if action == 'like':
        current_user.like_post(post)
        db.session.commit()
    if action == 'unlike':
        current_user.unlike_post(post)
        db.session.commit()
    return redirect(request.referrer)

然后，当您列出自己的帖子时，设置锚点如下:

Then when you're listing your posts, set your anchors something like this:

{% for post in posts %}
  {% if current_user.has_liked_post(post) %}
    <a href="{{ url_for('like_action', post_id=post.id, action='unlike') }}">Unlike</a>
  {% else %}
    <a href="{{ url_for('like_action', post_id=post.id, action='like') }}">Like</a>
  {% endif %}
{% endfor %}

让我们假设您的Post模型看起来像这样:

Let's assume your Post model looks something like this:

class Post(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    body = db.Column(db.Text)
    author_id = db.Column(db.Integer, db.ForeignKey('user.id'))
    recipient_id = db.Column(db.Integer, db.ForeignKey('user.id'))

    likes = db.relationship('PostLike', backref='post', lazy='dynamic')

您将使用:

p = Post.query.filter_by(id=1).first()
p.likes.count()

或者，您可以在.html文件中使用它:

Or, you'd use this in your .html file:

{% for post in posts %}
  {% if current_user.has_liked_post(post) %}
    <a href="{{ url_for('like_action', post_id=post.id, action='unlike') }}">Unlike</a>
  {% else %}
    <a href="{{ url_for('like_action', post_id=post.id, action='like') }}">Like</a>
  {% endif %}
  {{ post.likes.count() }} likes
{% endfor %}

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