Move make_content_disposition into HTTPResponse module

modified:   src/OFS/ObjectManager.py
modified:   src/ZPublisher/HTTPResponse.py
deleted:    src/ZPublisher/http_header_utils.py
modified:   src/ZPublisher/tests/testHTTPResponse.py
deleted:    src/ZPublisher/tests/test_http_header_utils.py

src/OFS/ObjectManager.py

@@ -61,7 +61,7 @@
 from zope.interface.interfaces import ComponentLookupError
 from zope.lifecycleevent import ObjectAddedEvent
 from zope.lifecycleevent import ObjectRemovedEvent
-from ZPublisher.http_header_utils import make_content_disposition
+from ZPublisher.HTTPResponse import make_content_disposition
 
 
 # Constants: __replaceable__ flags:

src/ZPublisher/HTTPResponse.py

@@ -115,6 +115,30 @@ def build_http_date(when):
         WEEKDAYNAME[wd], day, MONTHNAME[month], year, hh, mm, ss)
 
 
+def make_content_disposition(disposition, file_name):
+    """Create HTTP header for downloading a file with a UTF-8 filename.
+
+    See this and related answers: https://stackoverflow.com/a/8996249/2173868.
+    """
+    header = f'{disposition}'
+    try:
+        file_name.encode('us-ascii')
+    except UnicodeEncodeError:
+        # the file cannot be encoded using the `us-ascii` encoding
+        # which is advocated by RFC 7230 - 7237
+        #
+        # a special header has to be crafted
+        # also see https://tools.ietf.org/html/rfc6266#appendix-D
+        encoded_file_name = file_name.encode('us-ascii', errors='ignore')
+        header += f'; filename="{encoded_file_name}"'
+        quoted_file_name = quote(file_name)
+        header += f'; filename*=UTF-8\'\'{quoted_file_name}'
+        return header
+    else:
+        header += f'; filename="{file_name}"'
+        return header
+
+
 class HTTPBaseResponse(BaseResponse):
     """ An object representation of an HTTP response.
 

src/ZPublisher/tests/testHTTPResponse.py

@@ -8,6 +8,7 @@
 from zExceptions import NotFound
 from zExceptions import ResourceLockedError
 from zExceptions import Unauthorized
+from ZPublisher.HTTPResponse import make_content_disposition
 
 
 class HTTPResponseTests(unittest.TestCase):
@@ -1373,3 +1374,29 @@ def test_exception_500_text(self):
     def test_isHTML_not_decodable_bytes(self):
         response = self._makeOne()
         self.assertFalse(response.isHTML('bïñårÿ'.encode('latin1')))
+
+
+class MakeDispositionHeaderTests(unittest.TestCase):
+
+    def test_ascii(self):
+        self.assertEqual(
+            make_content_disposition('inline', 'iq.png'),
+            'inline; filename="iq.png"')
+
+    def test_latin_one(self):
+        self.assertEqual(
+            make_content_disposition('inline', 'Dänemark.png'),
+            'inline; filename="b\'Dnemark.png\'"; filename*=UTF-8\'\'D%C3%A4nemark.png'  # noqa: E501
+        )
+
+    def test_unicode(self):
+        """HTTP headers need to be latin-1 compatible
+
+        In order to offer file downloads which contain unicode file names,
+        the file name has to be treated in a special way, see
+        https://stackoverflow.com/questions/1361604 .
+        """
+        self.assertEqual(
+            make_content_disposition('inline', 'ıq.png'),
+            'inline; filename="b\'q.png\'"; filename*=UTF-8\'\'%C4%B1q.png'
+        )