fix appen_data invocation in WSGIFilterMiddleware

1 files changed, 6 insertions, 1 deletions

diff --git a/wsgitools/filters.py b/wsgitools/filters.py
index f892381..cfa6c36 100644
--- a/wsgitools/filters.py
+++ b/wsgitools/filters.py
@@ -144,9 +144,14 @@ class WSGIFilterMiddleware:
                                  [filter.filter_data(data) for data in ret]
                                  + list(filter.append_data()))
         ret = iter(ret)
+        def late_append_data():
+            """Invoke filter.append_data() after filter_data() has seen all
+            data."""
+            for data in filter.append_data():
+                yield data
         return CloseableIterator(modified_close,
                                  (filter.filter_data(data) for data in ret),
-                                 filter.append_data())
+                                 late_append_data())
 
 __all__.append("RequestLogWSGIFilter")
 class RequestLogWSGIFilter(BaseWSGIFilter):