creating roles module

jupyterhub/orm.py

@@ -90,6 +90,26 @@ class JSONDict(TypeDecorator):
         return value
 
 
+class JSONList(JSONDict):
+    """Represents an immutable structure as a json-encoded string (to be used for list type columns).
+
+    Usage::
+
+        JSONList(JSONDict)
+
+    """
+
+    def process_bind_param(self, value, dialect):
+        if isinstance(value, list) and value is not None:
+            value = json.dumps(value)
+        return value
+
+    def process_result_value(self, value, dialect):
+        if value is not None:
+            value = json.loads(value)
+        return value
+
+
 Base = declarative_base()
 Base.log = app_log
 
@@ -113,6 +133,41 @@ class Server(Base):
         return "<Server(%s:%s)>" % (self.ip, self.port)
 
 
+# user:role many:many mapping table
+user_role_map = Table(
+    'user_role_map',
+    Base.metadata,
+    Column('user_id', ForeignKey('users.id', ondelete='CASCADE'), primary_key=True),
+    Column('role_id', ForeignKey('roles.id', ondelete='CASCADE'), primary_key=True),
+)
+
+
+class Role(Base):
+    """User Roles"""
+
+    __tablename__ = 'roles'
+    id = Column(Integer, primary_key=True, autoincrement=True)
+    name = Column(Unicode(255), unique=True)
+    description = Column(Unicode(1023))
+    scopes = Column(JSONList)
+    users = relationship('User', secondary='user_role_map', backref='roles')
+
+    def __repr__(self):
+        return "<%s %s (%s) - scopes: %s>" % (
+            self.__class__.__name__,
+            self.name,
+            self.description,
+            self.scopes,
+        )
+
+    @classmethod
+    def find(cls, db, name):
+        """Find a role by name.
+        Returns None if not found.
+        """
+        return db.query(cls).filter(cls.name == name).first()
+
+
 # user:group many:many mapping table
 user_group_map = Table(
     'user_group_map',