diff --git a/django/core/handlers/wsgi.py b/django/core/handlers/wsgi.py
index e96ef44550..359d4b5425 100644
--- a/django/core/handlers/wsgi.py
+++ b/django/core/handlers/wsgi.py
@@ -251,12 +251,7 @@ class WSGIHandler(base.BaseHandler):
                 filelike = open(filename, 'rb')
                 return environ['wsgi.file_wrapper'](filelike, 
                         response.block_size)
-            else:
-                import os.path
-                if not os.path.exists(filename):
-                     raise Exception("Filename provided to HttpResponseSendFile does not exist.")
-                response_headers.append(('Content-Length', 
-                                         str(os.path.getsize(filename))))
+        
         start_response(status, response_headers)
         return response
 
diff --git a/django/http/__init__.py b/django/http/__init__.py
index 1d4875b2db..55592d628f 100644
--- a/django/http/__init__.py
+++ b/django/http/__init__.py
@@ -272,6 +272,7 @@ class HttpResponse(object):
 
     _status_code = 200
     _codec = None
+    _charset = None
 
     def __init__(self, content='', mimetype=None, status=None,
                  content_type=None, request=None):
@@ -446,6 +447,8 @@ class HttpResponseSendFile(HttpResponse):
         self.block_size = block_size
         self['Content-Disposition'] = ('attachment; filename=%s' %
              os.path.basename(path_to_file))
+        if not settings.HTTPRESPONSE_SENDFILE_HEADER and os.path.exists(path_to_file):
+            self['Content-Length'] = str(os.path.getsize(path_to_file))
         self._empty_content = False
 
     def set_empty_content(self):
@@ -457,6 +460,11 @@ class HttpResponseSendFile(HttpResponse):
         from django.core.servers.basehttp import FileWrapper
         return FileWrapper(self.get_file_handler(), self.block_size)
 
+    def _get_content(self):
+        return "".join(self.iter())
+
+    content = property(_get_content)    
+
     def get_file_handler(self):
         if not self.sendfile_fh:
             self.sendfile_fh = open(self.sendfile_filename, 'rb')