move token->helper into middleware to simplify code and error paths

shiftregister/app/context_processors.py

@@ -5,8 +5,6 @@ from .models import LoginToken
 def proc(request):
     context = {
         "DEBUG": settings.DEBUG,
+        "helper": request.helper,
     }
-    tk = LoginToken.objects.filter(pk=request.session.get("token")).first()
-    if tk:
-        context["helper"] = tk.helper
     return context

shiftregister/app/middleware.py

@@ -0,0 +1,23 @@
+from .models import LoginToken
+def check_helper(get_response):
+    # One-time configuration and initialization.
+
+    def middleware(request):
+        # Code to be executed for each request before
+        # the view (and later middleware) are called.
+        if request.session.get("token"):
+            tk =  LoginToken.objects.get(pk=request.session.get("token"))
+            if not tk:
+                del request.session["token"]
+            else:
+                request.helper = tk.helper
+            
+
+        response = get_response(request)
+
+        # Code to be executed for each request/response after
+        # the view is called.
+
+        return response
+
+    return middleware

shiftregister/app/views.py

@@ -14,14 +14,12 @@ def index(request):
     # dont show shifts starting in <60 minutes?
     # currently only sorts by date
     context = {}
-    helper = None
+    if request.helper:
-    if request.session.get("token"):
+        context["my_shifts"] = request.helper.shiftregistration_set.filter(
-        helper = LoginToken.objects.get(pk=request.session["token"]).helper
-        context["my_shifts"] = helper.shiftregistration_set.filter(
             shift__start_at__gt=timezone.now()
         ).order_by("shift__start_at")
         context["current_shift"] = (
-            helper.shiftregistration_set.annotate(
+            request.helper.shiftregistration_set.annotate(
                 shift_end=ExpressionWrapper(
                     F("shift__start_at") + F("shift__duration"),
                     output_field=DateTimeField(),
@@ -36,13 +34,13 @@ def index(request):
         .filter(start_at__gt=timezone.now(), room__required_helpers__gt=F("reg_count"))
         .order_by("start_at")
     )
-    if helper:
+    if request.helper:
         free_shifts = (
             Shift.objects.annotate(reg_count=Count("shiftregistration"))
             .filter(
                 start_at__gt=timezone.now(), room__required_helpers__gt=F("reg_count")
             )
-            .filter(~Q(shiftregistration__helper=helper))
+            .filter(~Q(shiftregistration__helper=request.helper))
             .order_by("start_at")
         )
     context["free_shifts"] = free_shifts
@@ -75,7 +73,9 @@ def logout(request):
 
 def register(request):
     # handle number already being registered(resend message?)
-    if request.session.get("token"):
+    if request.helper:
+        if request.session.get("last_seen_shift"):
+            return redirect("shift", shiftid=request.session["last_seen_shift"])
         return redirect("index")
     context = {}
     if request.method == "POST":
@@ -102,7 +102,7 @@ def register(request):
 
 def shift(request, shiftid):
     shift = get_object_or_404(Shift, pk=shiftid)
-    helper = None
+    helper = request.helper
     context = {
         "can_register": False,
         "is_registered": False,
@@ -114,8 +114,7 @@ def shift(request, shiftid):
     request.session["last_seen_shift"] = shiftid
     if shift.room.required_helpers > shift.shiftregistration_set.count():
         context["can_register"] = True
-    if request.session.get("token"):
+    if helper:
-        helper = LoginToken.objects.get(pk=request.session["token"]).helper
         context["helper"] = helper
         reg = ShiftRegistration.objects.filter(shift=shift, helper=helper)
         if reg:
@@ -126,7 +125,6 @@ def shift(request, shiftid):
     if request.method == "POST":
         if EmptyForm(request.POST).is_valid():
             if not helper:
-                # todo: add flash message that signup is required?
                 messages.add_message(
                     request,
                     messages.WARNING,
@@ -160,9 +158,8 @@ def cancel(request, shiftid):
         return redirect("shift", shiftid=shiftid)
     if not request.session.get("token"):
         return redirect("shift", shiftid=shiftid)
-    helper = LoginToken.objects.get(pk=request.session["token"]).helper
     shift = get_object_or_404(Shift, pk=shiftid)
-    reg = get_object_or_404(ShiftRegistration, helper=helper, shift=shift)
+    reg = get_object_or_404(ShiftRegistration, helper=request.helper, shift=shift)
     if reg.can_cancel():
         reg.delete()
         messages.add_message(

shiftregister/settings.py

@@ -52,6 +52,7 @@ MIDDLEWARE = [
     "django.contrib.auth.middleware.AuthenticationMiddleware",
     "django.contrib.messages.middleware.MessageMiddleware",
     "django.middleware.clickjacking.XFrameOptionsMiddleware",
+    "shiftregister.app.middleware.check_helper"
 ]
 
 ROOT_URLCONF = "shiftregister.urls"