Fix WSGIResponse.__call__ on Python 3. (#27)

Replace `isinstance(self.content, file)` with a duck type for the `read()` method. Having a read method is what PEP 333 defines as the minimum requirement for a "file-like" object.

2 files changed, 19 insertions, 2 deletions

diff --git a/paste/wsgiwrappers.py b/paste/wsgiwrappers.py
index 674054f..66bd896 100644
--- a/paste/wsgiwrappers.py
+++ b/paste/wsgiwrappers.py
@@ -360,11 +360,11 @@ class WSGIResponse(object):
         for c in self.cookies.values():
             response_headers.append(('Set-Cookie', c.output(header='')))
         start_response(status, response_headers)
-        is_file = isinstance(self.content, file)
+        is_file = hasattr(self.content, 'read')
         if 'wsgi.file_wrapper' in environ and is_file:
             return environ['wsgi.file_wrapper'](self.content)
         elif is_file:
-            return iter(lambda: self.content.read(), '')
+            return iter(lambda: self.content.read(), b'')
         return self.get_content()
 
     def determine_charset(self):
diff --git a/tests/test_wsgiwrappers.py b/tests/test_wsgiwrappers.py
index 75d03ed..43210c2 100644
--- a/tests/test_wsgiwrappers.py
+++ b/tests/test_wsgiwrappers.py
@@ -2,6 +2,7 @@
 # (c) 2007 Philip Jenvey; written for Paste (http://pythonpaste.org)
 # Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php
 import cgi
+import io
 from paste.fixture import TestApp
 from paste.wsgiwrappers import WSGIRequest, WSGIResponse
 import six
@@ -144,3 +145,19 @@ def test_wsgiresponse_charset():
             assert isinstance(data, six.text_type)
     finally:
         WSGIResponse.defaults._pop_object()
+
+def test_call_wsgiresponse():
+    resp = WSGIResponse(b'some content', 'application/octet-stream')
+    def sp(status, response_headers):
+        assert status == '200 OK'
+        assert sorted(response_headers) == [
+            ('cache-control', 'no-cache'),
+            ('content-type', 'application/octet-stream'),
+        ]
+    assert resp({}, sp) == [b'some content']
+    f = io.BytesIO(b'some content')
+    resp = WSGIResponse(f, 'application/octet-stream')
+    assert list(resp({}, sp)) == [b'some content']
+    f = io.BytesIO()
+    resp = WSGIResponse(f, 'application/octet-stream')
+    assert resp({'wsgi.file_wrapper': lambda x: x}, sp) is f