refactor: break document-only stuff into the paperless app

The `SessionOrBasicAuthMixin` and `StandardPagination` classes were
living in the documents app and I needed them in the new `reminders`
app, so this commit breaks them out of `documents` and puts them in the
central `paperless` app instead.

src/documents/mixins.py

@@ -1,8 +1,3 @@
-from django.contrib.auth.mixins import AccessMixin
-from django.contrib.auth import authenticate, login
-import base64
-
-
 class Renderable(object):
     """
     A handy mixin to make it easier/cleaner to print output based on a
@@ -12,46 +7,3 @@ class Renderable(object):
     def _render(self, text, verbosity):
         if self.verbosity >= verbosity:
             print(text)
-
-
-class SessionOrBasicAuthMixin(AccessMixin):
-    """
-    Session or Basic Authentication mixin for Django.
-    It determines if the requester is already logged in or if they have
-    provided proper http-authorization and returning the view if all goes
-    well, otherwise responding with a 401.
-
-    Base for mixin found here: https://djangosnippets.org/snippets/3073/
-    """
-
-    def dispatch(self, request, *args, **kwargs):
-
-        # check if user is authenticated via the session
-        if request.user.is_authenticated:
-
-            # Already logged in, just return the view.
-            return super(SessionOrBasicAuthMixin, self).dispatch(
-                request, *args, **kwargs
-            )
-
-        # apparently not authenticated via session, maybe via HTTP Basic?
-        if 'HTTP_AUTHORIZATION' in request.META:
-            auth = request.META['HTTP_AUTHORIZATION'].split()
-            if len(auth) == 2:
-                # NOTE: Support for only basic authentication
-                if auth[0].lower() == "basic":
-                    authString = base64.b64decode(auth[1]).decode('utf-8')
-                    uname, passwd = authString.split(':')
-                    user = authenticate(username=uname, password=passwd)
-                    if user is not None:
-                        if user.is_active:
-                            login(request, user)
-                            request.user = user
-                            return super(
-                                SessionOrBasicAuthMixin, self
-                            ).dispatch(
-                                request, *args, **kwargs
-                            )
-
-        # nope, really not authenticated
-        return self.handle_no_permission()

src/documents/views.py

@@ -2,15 +2,16 @@ from django.http import HttpResponse
 from django.views.decorators.csrf import csrf_exempt
 from django.views.generic import DetailView, FormView, TemplateView
 from django_filters.rest_framework import DjangoFilterBackend
-from rest_framework.filters import SearchFilter, OrderingFilter
 from paperless.db import GnuPG
+from paperless.mixins import SessionOrBasicAuthMixin
+from paperless.views import StandardPagination
+from rest_framework.filters import OrderingFilter, SearchFilter
 from rest_framework.mixins import (
     DestroyModelMixin,
     ListModelMixin,
     RetrieveModelMixin,
     UpdateModelMixin
 )
-from rest_framework.pagination import PageNumberPagination
 from rest_framework.permissions import IsAuthenticated
 from rest_framework.viewsets import (
     GenericViewSet,
@@ -27,7 +28,6 @@ from .serialisers import (
     LogSerializer,
     TagSerializer
 )
-from .mixins import SessionOrBasicAuthMixin
 
 
 class IndexView(TemplateView):
@@ -92,12 +92,6 @@ class PushView(SessionOrBasicAuthMixin, FormView):
         return HttpResponse("0")
 
 
-class StandardPagination(PageNumberPagination):
-    page_size = 25
-    page_size_query_param = "page-size"
-    max_page_size = 100000
-
-
 class CorrespondentViewSet(ModelViewSet):
     model = Correspondent
     queryset = Correspondent.objects.all()