add pages vote

judge/views/blog.py

@@ -7,6 +7,7 @@ from django.utils.translation import ugettext as _
 from django.views.generic import ListView
 
 from judge.comments import CommentedDetailView
+from judge.views.pagevote import PageVoteDetailView
 from judge.models import (
     BlogPost,
     Comment,
@@ -190,7 +191,7 @@ class CommentFeed(FeedView):
         return context
 
 
-class PostView(TitleMixin, CommentedDetailView):
+class PostView(TitleMixin, CommentedDetailView, PageVoteDetailView):
     model = BlogPost
     pk_url_kwarg = "id"
     context_object_name = "post"

judge/views/pagevote.py

@@ -0,0 +1,120 @@
+from django.contrib.auth.decorators import login_required
+from django.db import IntegrityError
+from django.db.models import F
+from django.http import (
+    Http404,
+    HttpResponse,
+    HttpResponseBadRequest,
+    HttpResponseForbidden,
+)
+from django.utils.translation import gettext as _
+from judge.models.pagevote import PageVote, PageVoteVoter
+from django.views.generic.base import TemplateResponseMixin
+from django.views.generic.detail import SingleObjectMixin
+
+from judge.dblock import LockModel
+from django.views.generic import View
+
+
+__all__ = [
+    "upvote_page",
+    "downvote_page",
+]
+
+@login_required
+def vote_page(request, delta):
+    if abs(delta) != 1:
+        return HttpResponseBadRequest(
+            _("Messing around, are we?"), content_type="text/plain"
+        )
+
+    if request.method != "POST":
+        return HttpResponseForbidden()
+
+    if "id" not in request.POST:
+        return HttpResponseBadRequest()
+
+    if (
+        not request.user.is_staff
+        and not request.profile.submission_set.filter(
+            points=F("problem__points")
+        ).exists()
+    ):
+        return HttpResponseBadRequest(
+            _("You must solve at least one problem before you can vote."),
+            content_type="text/plain",
+        )
+
+    try:
+        pagevote_id = int(request.POST["id"])
+    except ValueError:
+        return HttpResponseBadRequest()
+    else:
+        if not PageVote.objects.filter(id=pagevote_id).exists():
+            raise Http404()
+
+    vote = PageVoteVoter()
+    vote.pagevote_id = pagevote_id
+    vote.voter = request.profile
+    vote.score = delta
+
+    while True:
+        try:
+            vote.save()
+        except IntegrityError:
+            with LockModel(write=(PageVoteVoter,)):
+                try:
+                    vote = PageVoteVoter.objects.get(
+                        pagevote_id=pagevote_id, voter=request.profile
+                    )
+                except PageVoteVoter.DoesNotExist:
+                    # We must continue racing in case this is exploited to manipulate votes.
+                    continue
+                if -vote.score != delta:
+                    return HttpResponseBadRequest(
+                        _("You already voted."), content_type="text/plain"
+                    )
+                vote.delete()
+            PageVote.objects.filter(id=pagevote_id).update(score=F("score") - vote.score)
+        else:
+            PageVote.objects.filter(id=pagevote_id).update(score=F("score") + delta)
+        break
+    return HttpResponse("success", content_type="text/plain")
+
+
+def upvote_page(request):
+    return vote_page(request, 1)
+
+
+def downvote_page(request):
+    return vote_page(request, -1)
+
+class PageVoteDetailView(TemplateResponseMixin, SingleObjectMixin, View):
+    pagevote_page = None
+
+    def get_pagevote_page(self):
+        if self.pagevote_page is None:
+            raise NotImplementedError()
+        return self.pagevote_page
+
+    # def get(self, request, *args, **kwargs):
+    #     self.object = self.get_object()
+    #     return self.render_to_response(
+    #         self.get_context_data(
+    #             object=self.object,
+    #         )
+    #     )
+
+    def get_context_data(self, **kwargs):
+        context = super(PageVoteDetailView, self).get_context_data(**kwargs)
+        queryset = PageVote.objects.filter(page=self.get_comment_page())
+        if (queryset.exists() == False):
+            pagevote = PageVote(
+                page=self.get_comment_page(), score=0
+            )
+            pagevote.save()
+        context["pagevote"] = queryset.first()
+        return context
+
+    
+