How to display list of users who have liked a post in Flask app?

Question

I am new to Flask and I have created a social media blog using Flask by following videos of Corey Schafer and Miguel Grinberg, I have incorporated additional functionalities such as Liking a post and Commenting on a post. All of the functionalities that I have incorporated are functioning properly but I cannot view the users who have liked a post.

here is my routes.py file that has the like and ViewLikers route

@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) 

@app.route('/like/<int:post_id>/viewLikes')
@login_required
def viewLikers(post_id):
    post = Post.query.get_or_404(post_id)
    return render_template('viewLikes.html', likers=post.get_likers())

Here is my models.py file

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

class User(db.Model, UserMixin):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(20), unique=True, nullable=False)
    email = db.Column(db.String(120), unique=True, nullable=False)
    image_file = db.Column(db.String(20), nullable=False, default='default.jpg')
    password = db.Column(db.String(60), nullable=False)
    posts = db.relationship('Post', backref='author', lazy=True)

    followed = db.relationship(
        'User', secondary=followers,
        primaryjoin=(followers.c.follower_id == id),
        secondaryjoin=(followers.c.followed_id == id),
        backref=db.backref('followers', lazy='dynamic'), lazy='dynamic')

    liked = db.relationship(
        'PostLike',
        foreign_keys='PostLike.users_id',
        backref='user', lazy='dynamic')

    def like_post(self, post):
        if not self.has_liked_post(post):
            like = PostLike(users_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(
                users_id=self.id,
                post_id=post.id).delete()

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

class Post(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    title = db.Column(db.String(100), unique=True, nullable=False)
    date_posted = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
    content = db.Column(db.Text, nullable=False)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)

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


    def get_likers(self):
        return PostLike.query.filter_by(users_id =User.id, post_id=self.id)

But when I click on the viewLikes button in the template it gives me an error stating Function doesn't return any view

Answer 1

Simple error. In the last method you haven't returned the render_template. return render_template('')

Also call .first() on your post object