Updates for template changes in Django 1.8.

Use Django's render() shortcut rather than our own; create a
render_to_string patch that uses request/context appropriately; stub out
Context() when not needed; add TEMPLATES setting.

mapit/djangopatch.py

@@ -1,6 +1,15 @@
 import django
 import inspect
 
+# Django 1.8 changed how templates operate.
+if django.get_version() >= '1.8':
+    from django.template.loader import render_to_string
+else:
+    from django.template import loader, RequestContext
+    def render_to_string(template_name, context=None, request=None):
+        context_instance = RequestContext(request) if request else None
+        return loader.render_to_string(template_name, context, context_instance)
+
 # Django 1.6 renamed Manager's get_query_set to get_queryset, and the old
 # function will be removed entirely in 1.8. We work back to 1.4, so use a
 # metaclass to not worry about it.

mapit/middleware/view_error.py

@@ -2,9 +2,8 @@
 # and output it as either HTML or JSON appropriately
 
 from django import http
-from django.template import RequestContext
-from django.template.loader import render_to_string
 from mapit.shortcuts import output_json
+from mapit.djangopatch import render_to_string
 
 
 class ViewException(Exception):
@@ -27,6 +26,6 @@ def process_exception(self, request, exception):
             return response_type(render_to_string(
                 'mapit/%s.html' % code,
                 {'error': message},
-                context_instance=RequestContext(request)
+                request=request
             ))
         return output_json({'error': message}, code=code)

mapit/shortcuts.py

@@ -6,13 +6,19 @@
 from django.db import connection
 from django.conf import settings
 from django.shortcuts import get_object_or_404 as orig_get_object_or_404
-from django.shortcuts import render_to_response
-from django.template import loader, RequestContext, Context
+from django.template import loader
 from django.utils.six.moves import map
 from django.utils.encoding import smart_str
 from django.utils.translation import ugettext as _
 
 from mapit.iterables import defaultiter
+from mapit.djangopatch import render_to_string
+
+# In 1.8, we no longer need to pass a Context() so stub it out
+if django.get_version() < '1.8':
+    from django.template import Context
+else:
+    Context = lambda x: x
 
 from django.core.serializers.json import DjangoJSONEncoder
 # Assuming at least python 2.6, in Django < 1.6, the above class is either a
@@ -37,18 +43,10 @@ def default(self, o):
         return super(GEOS_JSONEncoder, self).default(o)
 
 
-def render(request, template_name, context=None):
-    if context is None:
-        context = {}
-    return render_to_response(
-        template_name, context, context_instance=RequestContext(request)
-    )
-
-
 def output_html(request, title, areas, **kwargs):
     kwargs['json_url'] = request.get_full_path().replace('.html', '')
     kwargs['title'] = title
-    tpl = loader.render_to_string('mapit/data.html', kwargs, context_instance=RequestContext(request))
+    tpl = render_to_string('mapit/data.html', kwargs, request=request)
     wraps = tpl.split('!!!DATA!!!')
 
     indent_areas = kwargs.get('indent_areas', False)

mapit/urls.py

@@ -1,7 +1,7 @@
 from django.conf.urls import include, url
 from django.conf import settings
+from django.shortcuts import render
 
-from mapit.shortcuts import render
 from mapit.views import areas, postcodes
 
 handler500 = 'mapit.shortcuts.json_500'

mapit/views/areas.py

@@ -13,10 +13,10 @@
 from django.http import HttpResponse, HttpResponseRedirect
 from django.core.urlresolvers import resolve, reverse
 from django.conf import settings
-from django.shortcuts import redirect
+from django.shortcuts import redirect, render
 
 from mapit.models import Area, Generation, Geometry, Code, Name, TransformError
-from mapit.shortcuts import output_json, output_html, render, get_object_or_404, set_timeout
+from mapit.shortcuts import output_json, output_html, get_object_or_404, set_timeout
 from mapit.middleware import ViewException
 from mapit.ratelimitcache import ratelimit
 from mapit import countries

mapit/views/postcodes.py

@@ -2,13 +2,13 @@
 import itertools
 from django.db.utils import DatabaseError
 
-from django.shortcuts import redirect
+from django.shortcuts import redirect, render
 from django.contrib.gis.geos import Point
 from django.contrib.gis.measure import D
 
 from mapit.models import Postcode, Area, Generation
 from mapit.utils import is_valid_postcode, is_valid_partial_postcode
-from mapit.shortcuts import output_json, get_object_or_404, set_timeout, render
+from mapit.shortcuts import output_json, get_object_or_404, set_timeout
 from mapit.middleware import ViewException
 from mapit.ratelimitcache import ratelimit
 from mapit.views.areas import add_codes

mapit_gb/urls.py

@@ -1,6 +1,6 @@
 from django.conf.urls import url
 
-from mapit.shortcuts import render
+from django.shortcuts import render
 
 urlpatterns = [
     url(r'^changelog$', render, {'template_name': 'mapit/changelog.html'}, 'mapit_changelog'),

project/settings.py

@@ -198,6 +198,16 @@
     'mapit.context_processors.analytics',
 )
 
+if django.get_version() >= '1.8':
+    TEMPLATES = [ {
+        'BACKEND': 'django.template.backends.django.DjangoTemplates',
+        'DIRS': TEMPLATE_DIRS,
+        'OPTIONS': {
+            'context_processors': map(lambda x: x.replace('django.core', 'django.template'), TEMPLATE_CONTEXT_PROCESSORS),
+            'loaders': TEMPLATE_LOADERS,
+        },
+    } ]
+
 INSTALLED_APPS = [
     'django.contrib.auth',
     'django.contrib.contenttypes',
@@ -208,7 +218,7 @@
     'django.contrib.staticfiles',
     'mapit',
 ]
-if django.VERSION < (1, 7):
+if django.get_version() < '1.7':
     INSTALLED_APPS.append('south')
 
 if MAPIT_COUNTRY: