Merge pull request #1828 from cherrypy/bugfix/1827-headermap-keytypev18.5.0

Potential fix for HeaderMap issues

2 files changed, 9 insertions, 5 deletions

diff --git a/CHANGES.rst b/CHANGES.rst
index 57d3fff1..1697a91f 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -1,6 +1,9 @@
 v18.5.0
 -------
 
+* :issue:`1827`: Fixed issue where bytes values in a ``HeaderMap``
+  would be converted to strings.
+
 * :pr:`1826`: Rely on
   `jaraco.collections <https://pypi.org/project/jaraco.collections>`_
   for its case-insensitive dictionary support.
diff --git a/cherrypy/lib/httputil.py b/cherrypy/lib/httputil.py
index 06004c9c..eedf8d89 100644
--- a/cherrypy/lib/httputil.py
+++ b/cherrypy/lib/httputil.py
@@ -391,12 +391,15 @@ class CaseInsensitiveDict(jaraco.collections.KeyTransformingDict):
 
     """A case-insensitive dict subclass.
 
-    Each key is changed on entry to str(key).title().
+    Each key is changed on entry to title case.
     """
 
     @staticmethod
     def transform_key(key):
-        return str(key).title()
+        if key is None:
+            # TODO(#1830): why?
+            return 'None'
+        return key.title()
 
 
 #   TEXT = <any OCTET except CTLs, but including LWS>
@@ -435,9 +438,7 @@ class HeaderMap(CaseInsensitiveDict):
 
     def elements(self, key):
         """Return a sorted list of HeaderElements for the given header."""
-        key = str(key).title()
-        value = self.get(key)
-        return header_elements(key, value)
+        return header_elements(self.transform_key(key), self.get(key))
 
     def values(self, key):
         """Return a sorted list of HeaderElement.value for the given header."""