Added backwards-compatible render_to_string

wagtail/utils/compat.py

@@ -1,4 +1,5 @@
 import django
+from django.template import loader
 
 
 def get_related_model(rel):
@@ -9,3 +10,22 @@ def get_related_model(rel):
         return rel.related_model
     else:
         return rel.model
+
+
+def render_to_string(template_name, context=None, request=None, **kwargs):
+    if django.VERSION >= (1, 8):
+        return loader.render_to_string(
+            template_name,
+            context=context,
+            request=request,
+            **kwargs
+        )
+    else:
+        # Backwards compatibility for Django 1.7 and below
+        from django.template.context import RequestContext
+        return loader.render_to_string(
+            template_name,
+            dictionary=context,
+            context_instance=RequestContext(request),
+            **kwargs
+        )

wagtail/wagtailadmin/modal_workflow.py

@@ -1,7 +1,8 @@
 import json
 
 from django.http import HttpResponse
-from django.template.loader import render_to_string
+
+from wagtail.utils.compat import render_to_string
 
 
 def render_modal_workflow(request, html_template, js_template, template_vars=None):

wagtail/wagtailadmin/site_summary.py

@@ -1,7 +1,6 @@
-from django.template.loader import render_to_string
-
 from wagtail.wagtailcore import hooks
 from wagtail.wagtailcore.models import Page
+from wagtail.utils.compat import render_to_string
 
 
 class SummaryItem(object):

wagtail/wagtailadmin/userbar.py

@@ -1,4 +1,4 @@
-from django.template.loader import render_to_string
+from wagtail.utils.compat import render_to_string
 
 
 class BaseItem(object):

wagtail/wagtailadmin/views/home.py

@@ -1,9 +1,9 @@
 from django.shortcuts import render
 from django.conf import settings
-from django.template.loader import render_to_string
 
 from wagtail.wagtailcore import hooks
 from wagtail.wagtailcore.models import PageRevision, UserPagePermissionsProxy
+from wagtail.utils.compat import render_to_string
 
 from wagtail.wagtailadmin.site_summary import SiteSummaryPanel
 

wagtail/wagtailimages/views/multiple.py

@@ -6,7 +6,6 @@ from django.views.decorators.http import require_POST
 from django.core.exceptions import PermissionDenied
 from django.views.decorators.vary import vary_on_headers
 from django.http import HttpResponse, HttpResponseBadRequest
-from django.template.loader import render_to_string
 from django.utils.encoding import force_text
 
 from wagtail.wagtailsearch.backends import get_search_backends
@@ -20,6 +19,7 @@ from wagtail.wagtailimages.fields import (
     ALLOWED_EXTENSIONS,
     FILE_TOO_LARGE_ERROR,
 )
+from wagtail.utils.compat import render_to_string
 
 
 def json_response(document):