Add IP bans

Users can be banned by IP address now, either by singular IP or in an IP
range. If they are banned and attempt to post, they will be met with a
"you are banned until X date" screen.

There are a few loose threads with this, and IP bans may be obsolete if
I decide to go the accounts-required-for-posting route. But I think this
is a good start for 4chan style posting.

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

board/views.py

@@ -1,23 +1,27 @@
 from django.conf import settings
 from django.http import Http404, HttpResponseRedirect
-from django.shortcuts import render, get_object_or_404
+from django.shortcuts import get_object_or_404
 from django.views.generic import DetailView
+from django.views.generic.base import TemplateView
 from django.views.generic.edit import CreateView
 from django.urls import reverse, reverse_lazy
-from board.models import Post, Board, Report, ReportRecord
 from board.forms import PostForm, ReplyForm, ReportForm
+from board.models import Ban, Post, Board, Report
+from board.utils import get_client_ip, get_ip_bans
 
-__all__ = ("BoardView", "PostView", "ReportView")
+__all__ = ("BannedView", "BoardView", "PostView", "ReportView")
 
 
-def get_client_ip(request):
-    "Get the IP address of a client-side request. Shamelessly copy/pasted from StackOverflow."
-    x_forwarded_for = request.META.get("HTTP_X_FORWARDED_FOR")
-    if x_forwarded_for:
-        ip = x_forwarded_for.split(",")[0]
-    else:
-        ip = request.META.get("REMOTE_ADDR")
-    return ip
+class BannedView(TemplateView):
+    template_name = "board/banned.html"
+
+    def get_context_data(self, **kwargs):
+        context = super(TemplateView, self).get_context_data(**kwargs)
+        ip = get_client_ip(self.request)
+        bans = get_ip_bans(ip)
+        context["bans"] = bans
+        context["ip"] = ip
+        return context
 
 
 class CreatePostView(CreateView):
@@ -46,6 +50,20 @@ class CreatePostView(CreateView):
         kwargs["ip"] = get_client_ip(self.request)
         return kwargs
 
+    def dispatch(self, request, *args, **kwargs):
+        self._set_board(kwargs["url"])
+        if request.method == "POST":
+            ip = get_client_ip(request)
+            bans = [
+                ban
+                for ban in get_ip_bans(ip)
+                if ban.board == self.board or not ban.board
+            ]
+            if bans:
+                return HttpResponseRedirect(reverse("board:banned"))
+
+        return super(CreatePostView, self).dispatch(request, *args, **kwargs)
+
 
 class BoardView(CreatePostView):
     model = Post