282 lines
		
	
	
		
			11 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			282 lines
		
	
	
		
			11 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
| """passbook multi-stage authentication engine"""
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| from traceback import format_tb
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| from typing import Any, Dict, Optional
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| 
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| from django.http import (
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|     Http404,
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|     HttpRequest,
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|     HttpResponse,
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|     HttpResponseRedirect,
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|     JsonResponse,
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| )
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| from django.shortcuts import get_object_or_404, redirect, render, reverse
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| from django.template.response import TemplateResponse
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| from django.utils.decorators import method_decorator
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| from django.views.decorators.clickjacking import xframe_options_sameorigin
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| from django.views.generic import TemplateView, View
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| from structlog import get_logger
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| 
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| from passbook.audit.models import cleanse_dict
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| from passbook.core.views.utils import PermissionDeniedView
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| from passbook.flows.exceptions import EmptyFlowException, FlowNonApplicableException
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| from passbook.flows.models import Flow, FlowDesignation, Stage
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| from passbook.flows.planner import FlowPlan, FlowPlanner
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| from passbook.lib.utils.reflection import class_to_path, path_to_class
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| from passbook.lib.utils.urls import is_url_absolute, redirect_with_qs
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| from passbook.lib.views import bad_request_message
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| 
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| LOGGER = get_logger()
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| # Argument used to redirect user after login
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| NEXT_ARG_NAME = "next"
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| SESSION_KEY_PLAN = "passbook_flows_plan"
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| SESSION_KEY_APPLICATION_PRE = "passbook_flows_application_pre"
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| SESSION_KEY_GET = "passbook_flows_get"
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| 
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| 
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| @method_decorator(xframe_options_sameorigin, name="dispatch")
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| class FlowExecutorView(View):
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|     """Stage 1 Flow executor, passing requests to Stage Views"""
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| 
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|     flow: Flow
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| 
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|     plan: Optional[FlowPlan] = None
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|     current_stage: Stage
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|     current_stage_view: View
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| 
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|     def setup(self, request: HttpRequest, flow_slug: str):
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|         super().setup(request, flow_slug=flow_slug)
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|         self.flow = get_object_or_404(Flow.objects.select_related(), slug=flow_slug)
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| 
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|     def handle_invalid_flow(self, exc: BaseException) -> HttpResponse:
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|         """When a flow is non-applicable check if user is on the correct domain"""
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|         if NEXT_ARG_NAME in self.request.GET:
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|             if not is_url_absolute(self.request.GET.get(NEXT_ARG_NAME)):
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|                 LOGGER.debug("f(exec): Redirecting to next on fail")
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|                 return redirect(self.request.GET.get(NEXT_ARG_NAME))
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|         message = exc.__doc__ if exc.__doc__ else str(exc)
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|         return bad_request_message(self.request, message)
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| 
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|     def dispatch(self, request: HttpRequest, flow_slug: str) -> HttpResponse:
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|         # Early check if theres an active Plan for the current session
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|         if SESSION_KEY_PLAN in self.request.session:
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|             self.plan = self.request.session[SESSION_KEY_PLAN]
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|             if self.plan.flow_pk != self.flow.pk.hex:
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|                 LOGGER.warning(
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|                     "f(exec): Found existing plan for other flow, deleteing plan",
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|                     flow_slug=flow_slug,
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|                 )
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|                 # Existing plan is deleted from session and instance
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|                 self.plan = None
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|                 self.cancel()
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|             LOGGER.debug("f(exec): Continuing existing plan", flow_slug=flow_slug)
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| 
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|         # Don't check session again as we've either already loaded the plan or we need to plan
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|         if not self.plan:
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|             LOGGER.debug(
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|                 "f(exec): No active Plan found, initiating planner", flow_slug=flow_slug
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|             )
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|             try:
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|                 self.plan = self._initiate_plan()
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|             except FlowNonApplicableException as exc:
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|                 LOGGER.warning("f(exec): Flow not applicable to current user", exc=exc)
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|                 return self.handle_invalid_flow(exc)
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|             except EmptyFlowException as exc:
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|                 LOGGER.warning("f(exec): Flow is empty", exc=exc)
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|                 return self.handle_invalid_flow(exc)
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|         # We don't save the Plan after getting the next stage
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|         # as it hasn't been successfully passed yet
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|         self.current_stage = self.plan.next()
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|         LOGGER.debug(
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|             "f(exec): Current stage",
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|             current_stage=self.current_stage,
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|             flow_slug=self.flow.slug,
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|         )
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|         if not self.current_stage:
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|             LOGGER.debug("f(exec): no more stages, flow is done.")
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|             return self._flow_done()
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|         stage_cls = path_to_class(self.current_stage.type)
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|         self.current_stage_view = stage_cls(self)
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|         self.current_stage_view.args = self.args
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|         self.current_stage_view.kwargs = self.kwargs
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|         self.current_stage_view.request = request
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|         return super().dispatch(request)
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| 
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|     def get(self, request: HttpRequest, *args, **kwargs) -> HttpResponse:
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|         """pass get request to current stage"""
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|         LOGGER.debug(
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|             "f(exec): Passing GET",
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|             view_class=class_to_path(self.current_stage_view.__class__),
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|             stage=self.current_stage,
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|             flow_slug=self.flow.slug,
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|         )
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|         try:
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|             stage_response = self.current_stage_view.get(request, *args, **kwargs)
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|             return to_stage_response(request, stage_response)
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|         except Exception as exc:  # pylint: disable=broad-except
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|             LOGGER.exception(exc)
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|             return to_stage_response(
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|                 request,
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|                 render(
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|                     request,
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|                     "flows/error.html",
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|                     {"error": exc, "tb": "".join(format_tb(exc.__traceback__))},
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|                 ),
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|             )
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| 
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|     def post(self, request: HttpRequest, *args, **kwargs) -> HttpResponse:
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|         """pass post request to current stage"""
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|         LOGGER.debug(
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|             "f(exec): Passing POST",
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|             view_class=class_to_path(self.current_stage_view.__class__),
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|             stage=self.current_stage,
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|             flow_slug=self.flow.slug,
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|         )
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|         try:
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|             stage_response = self.current_stage_view.post(request, *args, **kwargs)
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|             return to_stage_response(request, stage_response)
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|         except Exception as exc:  # pylint: disable=broad-except
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|             LOGGER.exception(exc)
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|             return to_stage_response(
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|                 request,
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|                 render(
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|                     request,
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|                     "flows/error.html",
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|                     {"error": exc, "tb": "".join(format_tb(exc.__traceback__))},
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|                 ),
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|             )
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| 
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|     def _initiate_plan(self) -> FlowPlan:
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|         planner = FlowPlanner(self.flow)
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|         plan = planner.plan(self.request)
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|         self.request.session[SESSION_KEY_PLAN] = plan
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|         return plan
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| 
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|     def _flow_done(self) -> HttpResponse:
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|         """User Successfully passed all stages"""
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|         # Since this is wrapped by the ExecutorShell, the next argument is saved in the session
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|         # extract the next param before cancel as that cleans it
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|         next_param = self.request.session.get(SESSION_KEY_GET, {}).get(
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|             NEXT_ARG_NAME, "passbook_core:overview"
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|         )
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|         self.cancel()
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|         return redirect_with_qs(next_param)
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| 
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|     def stage_ok(self) -> HttpResponse:
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|         """Callback called by stages upon successful completion.
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|         Persists updated plan and context to session."""
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|         LOGGER.debug(
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|             "f(exec): Stage ok",
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|             stage_class=class_to_path(self.current_stage_view.__class__),
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|             flow_slug=self.flow.slug,
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|         )
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|         # We call plan.next here to check for re-evaluate markers
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|         # this is important so we can save the result
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|         # and we don't have to re-evaluate the policies each request
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|         self.plan.next()
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|         self.plan.pop()
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|         self.request.session[SESSION_KEY_PLAN] = self.plan
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|         if self.plan.stages:
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|             LOGGER.debug(
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|                 "f(exec): Continuing with next stage",
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|                 reamining=len(self.plan.stages),
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|                 flow_slug=self.flow.slug,
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|             )
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|             return redirect_with_qs(
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|                 "passbook_flows:flow-executor", self.request.GET, **self.kwargs
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|             )
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|         # User passed all stages
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|         LOGGER.debug(
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|             "f(exec): User passed all stages",
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|             flow_slug=self.flow.slug,
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|             context=cleanse_dict(self.plan.context),
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|         )
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|         return self._flow_done()
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| 
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|     def stage_invalid(self) -> HttpResponse:
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|         """Callback used stage when data is correct but a policy denies access
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|         or the user account is disabled."""
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|         LOGGER.debug("f(exec): Stage invalid", flow_slug=self.flow.slug)
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|         self.cancel()
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|         return redirect_with_qs("passbook_flows:denied", self.request.GET)
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| 
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|     def cancel(self):
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|         """Cancel current execution and return a redirect"""
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|         keys_to_delete = [
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|             SESSION_KEY_APPLICATION_PRE,
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|             SESSION_KEY_PLAN,
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|             SESSION_KEY_GET,
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|         ]
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|         for key in keys_to_delete:
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|             if key in self.request.session:
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|                 del self.request.session[key]
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| 
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| 
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| class FlowPermissionDeniedView(PermissionDeniedView):
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|     """User could not be authenticated"""
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| 
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| 
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| class FlowExecutorShellView(TemplateView):
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|     """Executor Shell view, loads a dummy card with a spinner
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|     that loads the next stage in the background."""
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| 
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|     template_name = "flows/shell.html"
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| 
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|     def get_context_data(self, **kwargs) -> Dict[str, Any]:
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|         kwargs["exec_url"] = reverse("passbook_flows:flow-executor", kwargs=self.kwargs)
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|         kwargs["msg_url"] = reverse("passbook_api:messages-list")
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|         self.request.session[SESSION_KEY_GET] = self.request.GET
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|         return kwargs
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| 
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| 
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| class CancelView(View):
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|     """View which canels the currently active plan"""
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| 
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|     def get(self, request: HttpRequest) -> HttpResponse:
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|         """View which canels the currently active plan"""
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|         if SESSION_KEY_PLAN in request.session:
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|             del request.session[SESSION_KEY_PLAN]
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|             LOGGER.debug("Canceled current plan")
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|         return redirect("passbook_core:overview")
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| 
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| 
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| class ToDefaultFlow(View):
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|     """Redirect to default flow matching by designation"""
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| 
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|     designation: Optional[FlowDesignation] = None
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| 
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|     def dispatch(self, request: HttpRequest) -> HttpResponse:
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|         flow = Flow.with_policy(request, designation=self.designation)
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|         if not flow:
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|             raise Http404
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|         # If user already has a pending plan, clear it so we don't have to later.
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|         if SESSION_KEY_PLAN in self.request.session:
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|             plan: FlowPlan = self.request.session[SESSION_KEY_PLAN]
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|             if plan.flow_pk != flow.pk.hex:
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|                 LOGGER.warning(
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|                     "f(def): Found existing plan for other flow, deleteing plan",
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|                     flow_slug=flow.slug,
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|                 )
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|                 del self.request.session[SESSION_KEY_PLAN]
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|         return redirect_with_qs(
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|             "passbook_flows:flow-executor-shell", request.GET, flow_slug=flow.slug
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|         )
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| 
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| 
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| def to_stage_response(request: HttpRequest, source: HttpResponse) -> HttpResponse:
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|     """Convert normal HttpResponse into JSON Response"""
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|     if isinstance(source, HttpResponseRedirect) or source.status_code == 302:
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|         redirect_url = source["Location"]
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|         if request.path != redirect_url:
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|             return JsonResponse({"type": "redirect", "to": redirect_url})
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|         return source
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|     if isinstance(source, TemplateResponse):
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|         return JsonResponse(
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|             {"type": "template", "body": source.render().content.decode("utf-8")}
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|         )
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|     # Check for actual HttpResponse (without isinstance as we dont want to check inheritance)
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|     if source.__class__ == HttpResponse:
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|         return JsonResponse(
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|             {"type": "template", "body": source.content.decode("utf-8")}
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|         )
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|     return source
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