ContentNotRenderedError after a django upgrade

Question

Here's a middleware that I use:

class StatsMiddleware(object):
    def process_view(self, request, view_func, view_args, view_kwargs):
        # get number of db queries before we do anything
        n = len(connection.queries)

        # time the view
        start = time.time()
        response = view_func(request, *view_args, **view_kwargs)
        totTime = time.time() - start

        # compute the db time for the queries just run
        queries = len(connection.queries) - n
        if queries:
        dbTime = reduce(add, [float(q['time']) 
                              for q in connection.queries[n:]])
        else:
            dbTime = 0.0

        # and backout python time
        pyTime = totTime - dbTime

        stats = {
        'totTime': totTime,
        'pyTime': pyTime,
        'dbTime': dbTime,
        'queries': queries,
        'sql': '<br />'.join([ '<div class="stats_sql_query">%s</div><div class="stats_sql_time">%s s</div>' % (q['sql'], q['time']) for q in connection.queries[n:]]),
        }

        # clean query cache
        db.reset_queries()

        # replace the comment if found            
        if response and response.content:
            s = response.content
            regexp = re.compile(r'(?P<cmt><!--\s*STATS:(?P<fmt>.*?)-->)')
            match = regexp.search(s)
            if match:
                s = s[:match.start('cmt')] + \
                    match.group('fmt') % stats + \
                    s[match.end('cmt'):]
                response.content = s

        return response

It has been working perfectly for me up to django 1.3 but this broke when I upgraded to django trunk (1.4+) today, with the exception:-

Traceback:
File "./../django-trunk/django/core/handlers/base.py" in get_response
  105.                         response = middleware_method(request, callback, callback_args, callback_kwargs)
File "misc/middleware.py" in process_view
  63.         if response and response.content:
File "./../django-trunk/django/template/response.py" in _get_content
  123.             raise ContentNotRenderedError('The response content must be '

Exception Type: ContentNotRenderedError at /
Exception Value: The response content must be rendered before it can be accessed.

Would appreciate it if some one using django trunk points me in the right direction. Thanks!

Answer 1

Hacktastic solution: You can guard against this by checking if the response has an is_rendered attribute and if so, that it is true before changing the STATS string as follows:

   if response:
        if (hasattr(response,'is_rendered') and response.is_rendered or not hasattr(response,'is_rendered') ) and response.content:
            s = response.content
            regexp = re.compile(r'(?P<cmt><!--\s*STATS:(?P<fmt>.*?)-->)')
            match = regexp.search(s)
            if match:
                s = s[:match.start('cmt')] + \
                    match.group('fmt') % stats + \
                    s[match.end('cmt'):]
                response.content = s

    return response