Modernize the render_subtemplate template tag

mayan/apps/common/templatetags/subtemplates_tags.py

@@ -1,53 +1,19 @@
 from __future__ import unicode_literals
 
-import re
-
-from django.template import (
-    Context, Library, Node, TemplateSyntaxError, Variable
-)
+from django.template import Context, Library
 from django.template.loader import get_template
 
 register = Library()
 
 
-class RenderSubtemplateNode(Node):
-    def __init__(self, template_name, template_context, var_name):
-        self.template_name = template_name
-        self.template_context = template_context
-        self.var_name = var_name
+@register.assignment_tag(takes_context=True)
+def render_subtemplate(context, template_name, template_context):
+    """
+    Renders the specified template with the mixed parent and
+    subtemplate contexts
+    """
 
-    def render(self, context):
-        template_name = Variable(self.template_name).resolve(context)
-        template_context = Variable(self.template_context).resolve(context)
+    new_context = Context(context)
+    new_context.update(Context(template_context))
+    return get_template(template_name).render(new_context)
 
-        new_context = Context(context)
-        new_context.update(Context(template_context, autoescape=context.autoescape))
-
-        csrf_token = context.get('csrf_token', None)
-        if csrf_token is not None:
-            new_context['csrf_token'] = csrf_token
-
-        context[self.var_name] = get_template(template_name).render(new_context)
-        return ''
-
-
-@register.tag
-def render_subtemplate(parser, token):
-    # This version uses a regular expression to parse tag contents.
-    try:
-        # Splitting by None == splitting by spaces.
-        tag_name, arg = token.contents.split(None, 1)
-    except ValueError:
-        raise TemplateSyntaxError('%r tag requires arguments' % token.contents.split()[0])
-    m = re.search(r'(.*?) (.*?) as (\w+)', arg)
-    if not m:
-        raise TemplateSyntaxError('%r tag had invalid arguments' % tag_name)
-    template_name, template_context, var_name = m.groups()
-
-    if (template_name[0] == template_name[-1] and template_name[0] in ('"', "'")):
-        raise TemplateSyntaxError('%r tag\'s template name argument should not be in quotes' % tag_name)
-
-    if (template_context[0] == template_context[-1] and template_context[0] in ('"', "'")):
-        raise TemplateSyntaxError('%r tag\'s template context argument should not be in quotes' % tag_name)
-
-    return RenderSubtemplateNode(template_name, template_context, var_name)