db.py

from os import environ
from hydra_client import HydraAdmin
from graphqlclient import GraphQLClient
import urllib
import json

GRAPHQL_URL = environ['GRAPHQL_URL']
GRAPHQL_CLIENT = GraphQLClient(GRAPHQL_URL)


class User():
    def __init__(self, username):
        self.username = username
        try:
            self._load_remote_user_info()
        except urllib.error.HTTPError as error:
            raise BackendConnectionError(
                error.code,
                error.headers,
                ("Error during retrieval of userdata - " + error.reason))

    def _load_remote_user_info(self):
        querystring = '''{{
        getUser(username: "{0}"){{
            email,
            applications{{
                edges{{
                    node{{
                        name
                    }}
                }}
            }},
            roles{{
                edges{{
                    node{{
                        name
                    }}
                }}
            }}
        }}}}'''.format(self.username)
        result = json.loads(GRAPHQL_CLIENT.execute(querystring))
        data = result["data"]["getUser"]
        self.applications = list(map(lambda x: x["node"]["name"],
                                     data["applications"]["edges"]))
        self.roles = list(map(lambda x: x["node"]["name"],
                                     data["roles"]["edges"]))
        self.email = data["email"]

    def has_app_permission(self, appname):
        return appname in self.applications

    def get_oauth_session(self):
        """Create openID Connect token

        Use the userdata stored in the user object to create an OpenID Connect token.
        The token will be passed to Hydra, which will store it and serve it to all OpenID Connect
        Clients, that successfully query the /userinfo endpoint. Every field in the "id_token"
        dictionary can be accessed through standard scopes and claims.
        See https://openid.net/specs/openid-connect-core-1_0.html#Claims

        Returns:
            OpenID Connect token of type dict
        """
        return {
            "id_token": {
                "name": self.username,
                "preferred_username": self.username,
                "email" : self.email,
                "openappstack_roles": self.roles}
        }


class BackendConnectionError(Exception):
    """Raised when requests to the backend server fail

    Attributes:
        code -- http response code
        headers -- http response headers
        reason -- reson for the error
    """
    def __init__(self, code, headers, reason):
        self.code = code
        self.headers = headers
        self.reason = reason