Keg-Auth 0.2.12

Demo

Typical usage is demonstrated in https://github.com/level12/keg-app-cookiecutter

Usage

• Installation

  • bare functionality: pip install keg-auth

  • mail (i.e. with a mail manager configured, see below): pip install keg-auth[mail]

  • JWT (for using JWT tokens as authenticators): pip install keg-auth[jwt]

  • LDAP (for using LDAP target for authentication): pip install keg-auth[ldap]

• Configuration

  • SERVER_NAME = ‘somehost’: required for Keg Auth when generating URL in create-user CLI command - include a port number if needed (e.g. localhost:5000)

  • PREFERRED_URL_SCHEME = ‘https’: this is important so that generated auth related URLS are

    secure. You could have an SSL redirect but by the time that would fire, the key would have already been sent in the URL.

  • KEGAUTH_TOKEN_EXPIRE_MINS: integer, defaults to 240 minutes (4 hours) - if mail functions are enabled and tokens in the model, affects the time a verification token remains valid

  • KEGAUTH_CLI_USER_ARGS: list of strings, defaults to [‘email’] - names arguments to be accepted by CLI user commands and passed to the model

  • Email settings

    • KEGAUTH_EMAIL_SITE_NAME = ‘Keg Application’: used in email body if mail is enabled

    • KEGAUTH_EMAIL_SITE_ABBR = ‘Keg App’: used in email subject if mail is enabled

    • Example message:

      • Subject: [Keg App] Password Reset Link

      • Body: Somebody asked to reset your password on Keg Application. If this was not you…

• Extensions

  • set up an auth manager (in app setup or extensions)

  • the entity registry hooks up user, group, bundle, and permission entities. You will need to create a registry to associate with the auth manager, and register your entities from the model (see model notes)

  • note that the mail_manager is optional. If a mail_manager is not given, no mail will be sent

  • permissions may be passed as simple string tokens, or as tuples of (token, description)

  from flask_mail import Mail
  from keg_auth import AuthManager, AuthMailManager, AuthEntityRegistry
  
  mail_ext = Mail()
  auth_mail_manager = AuthMailManager(mail_ext)
  auth_entity_registry = AuthEntityRegistry()
  
  _endpoints = {'after-login': 'public.home'}
  permissions = (
      ('auth-manage', 'manage users, groups, bundles, and view permissions'),
      ('app-permission1', 'access view Foo'),
      ('app-permission2', 'access the Bar area'),
  )
  
  auth_manager = AuthManager(mail_manager=auth_mail_manager, endpoints=_endpoints,
                             entity_registry=auth_entity_registry, permissions=permissions)
  auth_manager.init_app(app)

• Login Authenticators control validation of users

  • includes logic for verifying a user from a login route, and other view-layer operations needed for user workflow (e.g. verifying email, password resets, etc.)

  • authenticator may be specified on the auth_manager:

    • ‘keg’ is the default primary authenticator, and uses username/password

    • AuthManager(mail_ext, login_authenticator=LdapAuthenticator)

  • LDAP authentication

    • from keg_auth import LdapAuthenticator

    • uses pyldap, which needs to be installed: pip install keg-auth[ldap]

    • additional config:

      • KEGAUTH_LDAP_TEST_MODE: when True, bypasses LDAP calls. Defaults to False

      • KEGAUTH_LDAP_SERVER_URL: target LDAP server to use for queries

      • KEGAUTH_LDAP_DN_FORMAT: format-able string to set up for the query - ex. uid={},dc=example,dc=org

• Request Loaders run when a user is not in session, and identifying data is in the request

  • AuthManager(mail_ext, request_loaders=JwtRequestLoader)

  • token authenticators, like JwtRequestLoader, have a create_access_token method - token = auth_manager.get_request_loader('jwt').create_access_token(user)

  • JWT: - from keg_auth import JwtRequestLoader - uses flask-jwt-extended, which needs to be installed: pip install keg-auth[jwt]

• Blueprints

  • include an auth blueprint along with your app’s blueprints, which includes the login views and user/group/bundle management. Requires AuthManager instance:

  from keg_auth import make_blueprint
  from my_app.extensions import auth_manager
  auth_bp = make_blueprint(__name__, auth_manager)

• CLI is rudimentary, with just one create-user command in the auth group. You can extend the group by using the cli_group attribute on the app’s auth_manager, but you need access to the app during startup to do that. You can use an event signal to handle this - just be sure your app’s visit_modules has the location of the event.

  # in app definition
  visit_modules = ['.events']
  
  
  # in events module
  from keg.signals import init_complete
  
  from keg_auth_ta.cli import auth_cli_extensions
  
  
  @init_complete.connect
  def init_app_cli(app):
      auth_cli_extensions(app)
  
  
  # in cli
  def auth_cli_extensions(app):
      @app.auth_manager.cli_group.command('command-extension')
      def command_extension():
          pass

• CLI create-user command, by default, has one required argument (email). If you wish to have additional arguments, put the list of arg names in KEGAUTH_CLI_USER_ARGS config

• Model

  • create entities using the existing mixins, and register them with keg_auth

  • note: the User model assumes that the entity mixed with UserMixin will have a PK id

  • email address and token verification by email are in UserEmailMixin - i.e. if your app will not use email token verification for passwords, leave that mixin out

  from keg.db import db
  from keg_elements.db.mixins import DefaultColsMixin, MethodsMixin
  from keg_auth import UserMixin, UserEmailMixin, PermissionMixin, BundleMixin, GroupMixin
  
  from my_app.extensions import auth_entity_registry
  
  
  class EntityMixin(DefaultColsMixin, MethodsMixin):
      pass
  
  
  @auth_entity_registry.register_user
  class User(db.Model, UserEmailMixin, UserMixin, EntityMixin):
      __tablename__ = 'users'
  
  
  @auth_entity_registry.register_permission
  class Permission(db.Model, PermissionMixin, EntityMixin):
      __tablename__ = 'permissions'
  
      def __repr__(self):
          return '<Permission id={} token={}>'.format(self.id, self.token)
  
  
  @auth_entity_registry.register_bundle
  class Bundle(db.Model, BundleMixin, EntityMixin):
      __tablename__ = 'bundles'
  
  
  @auth_entity_registry.register_group
  class Group(db.Model, GroupMixin, EntityMixin):
      __tablename__ = 'groups'

• Navigation Helpers

  • Keg-Auth provides navigation helpers to set up a menu tree, for which nodes on the tree are restricted according to the authentication/authorization requirements of the target endpoint

    • Note: requirements are any class-level permission requirements. If authorization is defined by an instance-level check_auth method, that will not be used by the navigation helpers

  • Usage involves setting up a menu structure with NavItem/NavURL objects. Note that permissions on a route may be overridden for navigation purposes

  • Menus may be tracked on the auth manager, which will reset their cached access on login/logout

  • keg_auth/navigation.html template has a helper render_menu to render a given menu as a ul

    • {% import "keg_auth/navigation.html" as navigation %}

    • render_menu(auth_manager.menus['main'])

    • render_menu(auth_manager.menus['main'], expand_to_current=True)

    • Automatically expand/collapse menu groups for the currently-viewed item. Useful for vertical menus.

  • Collapsible groups can be added to navigation menus by nesting NavItems in the menu. The group item will get a nav_group attribute, which can be referred to in CSS.

    • NavItem('Auth Menu', NavItem(...)) will have a nav_group of #navgroup-auth-menu

    • NavItem('Auth Menu', NavItem(...), nav_group='foo') will have a nav_group of #navgroup-foo

  • NavItems can specify an icon to display in the menu item by passing an icon_class string to the NavItem constructor. e.g., NavItem('Title', NavURL(...), icon_class='fas fa-shopping-cart').

  • Example:

  from keg.signals import init_complete
  
  from keg_auth import NavItem, NavURL
  
  @init_complete.connect
  def init_navigation(app):
      app.auth_manager.add_navigation_menu(
          'main',
          NavItem(
              NavItem('Home', NavURL('public.home')),
              NavItem(
                  'Nesting',
                  NavItem('Secret1', NavURL('private.secret1')),
                  NavItem('Secret1 Class', NavURL('private.secret1-class')),
              ),
              NavItem('Permissions On Stock Methods', NavURL('private.secret2')),
              NavItem('Permissions On Methods', NavURL('private.someroute')),
              NavItem('Permissions On Class And Method', NavURL('private.secret4')),
              NavItem('Permissions On NavURL',
                   NavURL(
                       'private.secret3', requires_permissions='permission3'
                   )),
              NavItem('User Manage', NavURL('auth.user:add')),
          )
      )

• Templates

  • templates are provided for the auth views, as well as base crud templates

  • base templates are referenced from settings. The first of these defined is used: - BASE_TEMPLATE - KEGAUTH_BASE_TEMPLATE

• Views

  • views may be restricted for access using the requires* decorators

  • each decorator can be used as a class decorator or on individual view methods

  • additionally, the decorator may be used on a Blueprint to apply the requirement to all routes on the blueprint

  • requires_user

    • require a user to be authenticated before proceeding (authentication only)

    • usage: @requires_user or @requires_user() (both usage patterns are identical if no secondary authenticators are needed)

    • note: this is similar to flask_login.login_required, but can be used as a class/blueprint decorator

    • you may pass a custom on_authentication_failure callable to the decorator, else it will redirect to the login page

    • a decorated class/blueprint may have a custom on_authentication_failure instance method instead of passing one to the decorator

  • requires_permissions

    • require a user to be conditionally authorized before proceeding (authentication + authorization)

    • has_any and has_all helpers can be used to construct complex conditions, using string permission tokens, nested helpers, and callable methods

    • you may pass a custom on_authorization_failure callable to the decorator, else it will respond 403 Unauthorized

    • a decorated class/blueprint may have a custom on_authorization_failure instance method instead of passing one to the decorator

    • usage:

      • @requires_permissions(('token1', 'token2'))

      • @requires_permissions(has_any('token1', 'token2'))

      • @requires_permissions(has_all('token1', 'token2'))

      • @requires_permissions(has_all(has_any('token1', 'token2'), 'token3'))

      • @requires_permissions(custom_authorization_callable that takes user arg)

  • a standard CRUD view is provided which has add, edit, delete, and list “actions”

    • from keg_auth import CrudView

    • because the standard action routes are predefined, you can assign specific permission(s) to them in the view’s permissions dictionary, keyed by action (e.g. permissions[‘add’] = ‘foo’)

User Login During Testing

This library provides keg_auth.testing.AuthTestApp which is a sub-class of flask_webtest.TestApp to make it easy to set the logged-in user during testing:

from keg_auth.testing import AuthTestApp

class TestViews(object):

    def setup(self):
        ents.User.delete_cascaded()

    def test_authenticated_client(self):
        """
            Demonstrate logging in at the client level.  The login will apply to all requests made
            by this client.
        """
        user = ents.User.testing_create()
        client = AuthTestApp(flask.current_app, user=user)
        resp = client.get('/secret2', status=200)
        assert resp.text == 'secret2'

    def test_authenticated_request(self):
        """
            Demonstrate logging in at the request level.  The login will only apply to one request.
        """
        user = ents.User.testing_create(permissions=('permission1', 'permission2'))
        client = AuthTestApp(flask.current_app)

        resp = client.get('/secret-page', status=200, user=user)
        assert resp.text == 'secret-page'

        # User should only stick around for a single request (and will get a 302 redirect to the)
        # login view.
        client.get('/secret-page', status=302)

A helper class is also provided to set up a client and user, given the permissions specified on the class definition:

from keg_auth.testing import ViewTestBase

class TestMyView(ViewTestBase):
    permissions = 'permission1', 'permission2', ...

    def test_get(self):
        self.client.get('/foo')

Using Without Email Functions

Keg Auth is designed out of the box to use emailed tokens to:

• verify the email addresses on user records

• provide a method of initially setting passwords without the admin setting a known password

While this provides good security in many scenarios, there may be times when the email methods are not desired (for example, if an app will run in an environment where the internet is not accessible). Only a few changes are necessary from the examples above to achieve this:

• leave UserEmailMixin out of the User model

• do not specify a mail_manager when setting up AuthManager

Email/Reset Password functionality

• The JWT tokens in the email / reset password emails are salted with

  • username/email (depends on which is enabled)

  • password hash

  • last login utc

  • is_active (verified/enabled combination)

  This allows for tokens to become invalidate anytime of the following happens:

  • username/email changes

  • password hash changes

  • a user logs in (last login utc will be updated and invalidate the token)

  • is active (depending on the model this is calculated from is_enabled/is_verified fields)

0.2.12 released 2019-10-03

• support decorating flask class-based views (3d8a6cb)

• fix LDAP authenticator for missing user case (19d184e)

0.2.11 released 2019-09-27

• fix permission sync method and test hook (a56eda4)

• fix FontAwesome usage on CRUD list view template (64f759a)

• support lazy strings and icons in navigation helpers and templates (4473571)

• remove flask version pin (ab47362)

0.2.10 released 2019-09-18

• fix testing utils mock import to prevent needing mock dependency (da197df)

0.2.9 released 2019-07-27

• Provide a hook on the CRUD base class to allow overriding the default add url generation (#74) (7eea8bb)

0.2.8 released 2019-06-17

• resolve bug in testing permission existence check (feccb98)

0.2.7 released 2019-06-07

• make custom action access control easier (63921ee)

• enforce test permissions are specified to the auth manager (794f320)

• correct the MRO order in CRUD forms and testing models (2f4c451)

• add get_current_user helper method (cae02a2)

• make grid action column link CSS classes customizable (aa1bc21)

• ensure CRUD view passes in desired template args (aae3dad)

0.2.6 released 2019-02-12

• Merge pull request #60 from level12/move-sync-perms-to-entity (3181691)

• update readme to remove reference to view-scoped authenticators (514c202)

0.2.5 released 2018-11-14

• Allow make_blueprint to accept a custom blueprint class (fe635b2)

• Add a link to resend verification email (f7a6191)

• Add optional i18n support using morphi (790d3ab)

• Fix intermittent test failure resulting from login timestamp (cde083b)

• Refactor CRUD form/grid render to extract template args (34d4a20)

0.2.4

• Show verification URL on CLI even if mail flag is off

0.2.3

• Fix requires_user decorator for usage with blueprints

0.2.1

• Fix nav items to cache on per user basis

• Fix token generated in CLI having an unknown timezone applied

0.2.0

• Support permissions

• Decorate blueprints, classes, methods for user/permission requirements

• Support request loaders for tokens

0.1.0

• Initial release