model.py

# coding=utf-8
from datetime import datetime
from werkzeug.security import generate_password_hash, check_password_hash
from flask.ext.login import UserMixin, current_app, AnonymousUserMixin
from start import db
from itsdangerous import TimedJSONWebSignatureSerializer as Serializer
import hashlib
from flask import current_app, request
from markdown import markdown
import bleach


class Permission:
    FOLLOW = 0x01
    COMMENT = 0x02
    WRITE_ARTICLES = 0x04
    MODERATE_COMMENTS = 0x08
    ADMINISTER = 0x80

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 Role(db.Model):
    __tablename__ = 'roles'
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(64), unique=True)
    default = db.Column(db.Boolean, default=False, index=True)
    permissions = db.Column(db.Integer)
    users = db.relationship('User', backref='role', lazy='dynamic')

    @staticmethod
    def insert_roles():
        roles = {
            'User': (Permission.FOLLOW |
                     Permission.COMMENT |
                     Permission.WRITE_ARTICLES, True),
            'Moderator': (Permission.FOLLOW |
                          Permission.COMMENT |
                          Permission.WRITE_ARTICLES |
                          Permission.MODERATE_COMMENTS, False),
            'Administrator': (0xff, False)
        }
        for r in roles:
            role = Role.query.filter_by(name=r).first()
            if role is None:
                role = Role(name=r)
            role.permissions = roles[r][0]
            role.default = roles[r][1]
            db.session.add(role)
        db.session.commit()

    def __repr__(self):
        return '<Role %r>' % self.name


class User(UserMixin, db.Model):
    __tablename__ = 'users'
    id = db.Column(db.Integer, primary_key=True)
    email = db.Column(db.String(64), unique=True, index=True)
    username = db.Column(db.String(64), unique=True, index=True)
    password_hash = db.Column(db.String(128))
    confirmed = db.Column(db.Boolean, default=False)
    role_id = db.Column(db.Integer, db.ForeignKey('roles.id'))
    location = db.Column(db.String(64))
    name = db.Column(db.String(64))
    about_me = db.Column(db.Text())
    member_since = db.Column(db.DateTime(), default=datetime.utcnow)
    last_seen = db.Column(db.DateTime(), default=datetime.utcnow)
    avatar_hash = db.Column(db.String(32))
    posts = db.relationship('Post', backref='author', lazy='dynamic')
    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')
    comments = db.relationship('Comment', backref='author', lazy='dynamic')

    def __init__(self, **kwargs):
        super(User, self).__init__(**kwargs)
        if self.role is None:
            if self.email == current_app.config['FLASKY_ADMIN']:
                self.role = Role.query.filter_by(permissions=0xff).first()
            if self.role is None:
                self.role = Role.query.filter_by(default=True).first()
        if self.email is not None and self.avatar_hash is None:
            self.avatar_hash = hashlib.md5(
                self.email.encode('utf-8')).hexdigest()

    @property
    def followed_posts(self):
        return Post.query.join(Follow, Follow.followed_id == Post.author_id)\
            .filter(Follow.follower_id == self.id)

    def ping(self):
        self.last_seen = datetime.utcnow()
        db.session.add(self)
        db.session.commit()

    def gravatar(self, size=100, default='identicon', rating='g'):
        if request.is_secure:
            url = 'https://secure.gravatar.com/avatar'
        else:
            url = 'http://www.gravatar.com/avatar'
        hash = self.avatar_hash or hashlib.md5(self.email.encode('utf-8')).hexdigest()
        return '{url}/{hash}?s={size}&d={default}&r={rating}'.format(
            url=url, hash=hash, size=size, default=default, rating=rating)

    @property
    def password(self):
        raise AttributeError(u'密码为不可读字段')

    @password.setter
    def password(self, password):
        self.password_hash = generate_password_hash(password)

    def verify_password(self, password):
        return check_password_hash(self.password_hash.encode('utf-8'), password)

    def confirm(self, token):
        s = Serializer(current_app.config['SECRET_KEY'])
        try:
            data = s.loads(token)
        except:
            return False
        if data.get('confirm') != self.id:
            return False
        self.confirmed = True
        db.session.add(self)
        return True

    def generate_confirmation_token(self, expiration=3600):
        s = Serializer(current_app.config['SECRET_KEY'], expiration)
        return s.dumps({'confirm': self.id})

    @classmethod
    def get_user_by_token(cls, token):
        s = Serializer(current_app.config['SECRET_KEY'])
        try:
            data = s.loads(token)
        except:
            return None
        user_id = data.get('confirm')
        user = User.query.filter_by(id=user_id).first()
        return user

    def can(self, permissions):
        return self.role is not None and \
            (self.role.permissions & permissions) == permissions

    def is_administrator(self):
        return self.can(Permission.ADMINISTER)

    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


class AnonymousUser(AnonymousUserMixin):
    def can(self, permissions):
        return False

    def is_administrator(self):
        return False


class Post(db.Model):
    __tablename__ = 'posts'
    id = db.Column(db.Integer, primary_key=True)
    body = db.Column(db.Text)
    timestamp = db.Column(db.DateTime, index=True, default=datetime.utcnow)
    author_id = db.Column(db.Integer, db.ForeignKey('users.id'))
    body_html = db.Column(db.Text)
    comments = db.relationship('Comment', backref='post', lazy='dynamic')

    @staticmethod
    def on_changed_body(target, value, oldvalue, initiator):
        allowed_tags = ['a', 'abbr', 'acronym', 'b', 'blockquote', 'code',
                        'em', 'i', 'li', 'ol', 'pre', 'strong', 'ul',
                        'h1', 'h2', 'h3', 'p']
        target.body_html = bleach.linkify(bleach.clean(
            markdown(value, output_format='html'),
            tags=allowed_tags, strip=True))

db.event.listen(Post.body, 'set', Post.on_changed_body)


class Comment(db.Model):
    __tablename__ = 'comments'
    id = db.Column(db.Integer, primary_key=True)
    body = db.Column(db.Text)
    body_html = db.Column(db.Text)
    timestamp = db.Column(db.DateTime, index=True, default=datetime.utcnow)
    disabled = db.Column(db.Boolean)
    author_id = db.Column(db.Integer, db.ForeignKey('users.id'))
    post_id = db.Column(db.Integer, db.ForeignKey('posts.id'))

    @staticmethod
    def on_changed_body(target, value, oldvalue, initiator):
        allowed_tags = ['a', 'abbr', 'acronym', 'b', 'code', 'em', 'i',
                        'strong']
        target.body_html = bleach.linkify(bleach.clean(
            markdown(value, output_format='html'),
            tags=allowed_tags, strip=True))

db.event.listen(Comment.body, 'set', Comment.on_changed_body)