When the new policies are used (and only when the new policies are explicitly
used) headers turn into objects that have attributes based on their parsed
values, and can be set using objects that encapsulate the values, as well as
set directly from unicode strings. The folding algorithm then takes care of
encoding unicode where needed, and folding according to the highest level
syntactic objects.
With this patch only date and time headers are parsed as anything other than
unstructured, but that is all the helper methods in the existing API handle.
I do plan to add more parsers, and complete the set specified in the RFC
before the package becomes stable.
This patch primarily does two things: (1) it adds some internal-interface
methods to Policy that allow for Policy to control the parsing and folding of
headers in such a way that we can construct a backward compatibility policy
that is 100% compatible with the 3.2 API, while allowing a new policy to
implement the email6 API. (2) it adds that backward compatibility policy and
refactors the test suite so that the only differences between the 3.2
test_email.py file and the 3.3 test_email.py file is some small changes in
test framework and the addition of tests for bugs fixed that apply to the 3.2
API.
There are some additional teaks, such as moving just the code needed for the
compatibility policy into _policybase, so that the library code can import
only _policybase. That way the new code that will be added for email6
will only get imported when a non-compatibility policy is imported.
Éric pointed out that given that the default was documented as None, someone
would reasonably pass that to get the default behavior. In fixing the code to
use None, I noticed that the change to _charset was being done after it had
already been passed to MIMENonMultipart. The change to the test verifies that
the order is now correct.
Previously it would just accept the unicode, which would wind up as unicode in
the transfer-encoded message object, which is just wrong.
Patch by Jeff Knupp.
In Python2, if a unicode string was assigned as the value of a header,
email would automatically CTE encode it using the UTF8 charset.
This capability was lost in the Python3 translation, and this patch
restores it.
Patch by Ali Ikinci, assisted by R. David Murray.
I also added a fix for the mailbox test that was depending (with a comment
that it was a bad idea to so depend) on non-ASCII causing message_from_string
to raise an error. It now uses support.patch to induce an error during
message serialization.
In Python2, if a unicode string was assigned as the value of a header,
email would automatically CTE encode it using the UTF8 charset.
This capability was lost in the Python3 translation, and this patch
restores it.
Patch by Ali Ikinci, assisted by R. David Murray.
I also added a fix for the mailbox test that was depending (with a comment
that it was a bad idea to so depend) on non-ASCII causing message_from_string
to raise an error. It now uses support.patch to induce an error during
message serialization.
Analogous to the decode_header fix, this fix makes Header.append and
make_header correctly handle the unknown-8bit charset introduced by email5.1,
when the input to them is binary strings. Previous to this fix the
make_header(decode_header(x)) == x invariant was broken in the face of the
unknown-8bit charset.
This new interface will also allow for future planned enhancements
in control over the parser/generator without requiring any additional
complexity in the parser/generator API.
Patch reviewed by Éric Araujo and Barry Warsaw.
Why I consider this a bug rather than an API change: the API change was
to Message, which didn't used to return Headers unless you added them
yourself. Now it does (for 8bit binary header input), so decode_header
needs to be able to handle them.
R David Murray
Florent Xicluna
Ezio Melotti