Fix Issue15701 : add .headers attribute to urllib.error.HTTPError

Doc/library/urllib.error.rst

@@ -45,6 +45,13 @@ The following exceptions are raised by :mod:`urllib.error` as appropriate:
 
       This is usually a string explaining the reason for this error.
 
+   .. attribute:: headers
+
+      The HTTP response headers for the HTTP request that cause the
+      :exc:`HTTPError`.
+
+      .. versionadded:: 3.4
+
 .. exception:: ContentTooShortError(msg, content)
 
    This exception is raised when the :func:`urlretrieve` function detects that

Lib/test/test_urllib2.py

@@ -1539,11 +1539,15 @@ def test_HTTPError_interface():
     interface even though HTTPError is a subclass of URLError.
 
     >>> msg = 'something bad happened'
-    >>> url = code = hdrs = fp = None
+    >>> url = code = fp = None
+    >>> hdrs = 'Content-Length: 42'
     >>> err = urllib.error.HTTPError(url, code, msg, hdrs, fp)
     >>> assert hasattr(err, 'reason')
     >>> err.reason
     'something bad happened'
+    >>> assert hasattr(err, 'headers')
+    >>> err.headers
+    'Content-Length: 42'
     """
 
 def test_main(verbose=None):

Lib/urllib/error.py

@@ -61,6 +61,14 @@ class HTTPError(URLError, urllib.response.addinfourl):
     def reason(self):
         return self.msg
 
+    @property
+    def headers(self):
+        return self.hdrs
+
+    @headers.setter
+    def headers(self, headers):
+        self.hdrs = headers
+
 # exception raised when downloaded size does not match content-length
 class ContentTooShortError(URLError):
     def __init__(self, message, content):

Misc/NEWS

@@ -163,6 +163,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #15701: Add a .headers attribute to urllib.error.HTTPError. Patch
+  contributed by Berker Peksag.
+
 - Issue #15872: Fix 3.3 regression introduced by the new fd-based shutil.rmtree
   that caused it to not ignore certain errors when ignore_errors was set.
   Patch by Alessandro Moura and Serhiy Storchaka.