python flask web 博客实例 关注模块 3

1 app/models.py class Follow(db.Model): tablename = 'follows' follower_id = db.Column(db.Integer, db.ForeignKey('users.id'),primary_key=True) followed_id = db.Column(db.Integer, db.ForeignKey('users.id'),primary_key=True) timestamp = db.Column(db.DateTime, default=datetime.utcnow) class User(UserMixin, db.Model): def init(self, **kwargs): # ... self.follow(self) # ... followed = db.relationship('Follow',foreign_keys=[Follow.follower_id],backref=db.backref('follower', lazy='joined'),lazy='dynamic',cascade='all, delete-orphan') followers = db.relationship('Follow',foreign_keys=[Follow.followed_id],backref=db.backref('followed', lazy='joined'),lazy='dynamic',cascade='all, delete-orphan') def follow(self, user): if not self.is_following(user): f = Follow(follower=self, followed=user) db.session.add(f) def unfollow(self, user): f = self.followed.filter_by(followed_id=user.id).first() if f: db.session.delete(f) def is_following(self, user): return self.followed.filter_by( followed_id=user.id).first() is not None def is_followed_by(self, user): return self.followers.filter_by( follower_id=user.id).first() is not None @property def followed_posts(self): return Post.query.join(Follow, Follow.followed_id == Post.author_id).filter(Follow.follower_id == self.id) @staticmethod def add_self_follows(): for user in User.query.all(): if not user.is_following(user): user.follow(user) db.session.add(user) db.session.commit()

2 app/templates/user.html {% if current_user.can(Permission.FOLLOW) and user != current_user %} {% if not current_user.is_following(user) %} <a href="{{ url_for('.follow', username=user.username) }}" class="btn btn-primary">Follow</a> {% else %} <a href="{{ url_for('.unfollow', username=user.username) }}" class="btn btn-default">Unfollow</a> {% endif %} {% endif %} <a href="{{ url_for('.followers', username=user.username) }}"> Followers: <span class="badge">{{ user.followers.count() }}</span> </a> <a href="{{ url_for('.followed_by', username=user.username) }}"> Following: <span class="badge">{{ user.followed.count() }}</span> </a> {% if current_user.is_authenticated() and user != current_user and user.is_following(current_user) %} | <span class="label label-default">Follows you</span> {% endif %}

3 　app/main/views.py @app.route('/', methods = ['GET', 'POST']) def index(): # ... show_followed = False if current_user.is_authenticated(): show_followed = bool(request.cookies.get('show_followed', '')) if show_followed: query = current_user.followed_posts else: query = Post.query pagination = query.order_by(Post.timestamp.desc()).paginate(page, per_page=current_app.config['FLASKY_POSTS_PER_PAGE'],error_out=False) posts = pagination.items return render_template('index.html', form=form, posts=posts,show_followed=show_followed, pagination=pagination) @main.route('/follow/<username>') @login_required @permission_required(Permission.FOLLOW) def follow(username): user = User.query.filter_by(username=username).first() if user is None: flash('Invalid user.') return redirect(url_for('.index')) if current_user.is_following(user): flash('You are already following this user.') return redirect(url_for('.user', username=username)) current_user.follow(user) flash('You are now following %s.' % username) return redirect(url_for('.user', username=username)) @main.route('/followers/<username>') def followers(username): user = User.query.filter_by(username=username).first() if user is None: flash('Invalid user.') return redirect(url_for('.index')) page = request.args.get('page', 1, type=int) pagination = user.followers.paginate(page, per_page=current_app.config['FLASKY_FOLLOWERS_PER_PAGE'],error_out=False) follows = [{'user': item.follower, 'timestamp': item.timestamp} for item in pagination.items] return render_template('followers.html', user=user, title="Followers of",endpoint='.followers', pagination=pagination,follows=follows) @main.route('/all') @login_required def show_all(): resp = make_response(redirect(url_for('.index'))) resp.set_cookie('show_followed', '', max_age=30246060) return resp @main.route('/followed') @login_required def show_followed(): resp = make_response(redirect(url_for('.index'))) resp.set_cookie('show_followed', '1', max_age=30246060) return resp

多对多关系

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级联查询

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