models.py

from datetime import datetime
import hashlib
from werkzeug.security import generate_password_hash, check_password_hash
from itsdangerous import TimedJSONWebSignatureSerializer as Serializer
from markdown import markdown
import bleach
from flask import current_app, request, url_for
from flask_login import UserMixin, AnonymousUserMixin
from app.exceptions import ValidationError
from . import db, login_manager


class Permission:
    STUDENT = 4
    LECTURER = 8
    ADMIN = 16

class User(db.Model):
    __tablename__ = 'Users'
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(64), unique=True)
    password = db.Column(db.String(64), unique=True)
    default = db.Column(db.Boolean, default=False, index=True)
    type = db.Column(db.String(64))

    def __init__(self, **kwargs):
        super(User, self).__init__(**kwargs)
        if self.permissions is None:
            self.permissions = 0

    @staticmethod
    def insert_roles():
        roles = {
            'Student': [Permission.FOLLOW, Permission.COMMENT, Permission.WRITE],
            'Lecturer': [Permission.FOLLOW, Permission.COMMENT,
                          Permission.WRITE, Permission.MODERATE],
            'Administrator': [Permission.FOLLOW, Permission.COMMENT,
                              Permission.WRITE, Permission.MODERATE,
                              Permission.ADMIN],
        }
        default_role = 'User'
        for r in roles:
            role = User.query.filter_by(name=r).first()
            if role is None:
                role = User(name=r)
            role.reset_permissions()
            for perm in roles[r]:
                role.add_permission(perm)
            role.default = (role.name == default_role)
            db.session.add(role)
        db.session.commit()

    def add_permission(self, perm):
        if not self.has_permission(perm):
            self.permissions += perm

    def remove_permission(self, perm):
        if self.has_permission(perm):
            self.permissions -= perm

    def reset_permissions(self):
        self.permissions = 0

    def has_permission(self, perm):
        return self.permissions & perm == perm

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