fix formataddr

This adds a local utility function `formataddr` which acts as the direct
inverse of `email.utils.parseaddr`.

The problem with `email.utils.formataddr` is (currently) that
- it encodes non-ascii characters and
- it does not re-introduce quotes around the real name parts in case
parseaddr removed them:

    >>>parseaddr('"Ö, Ä" <a@b.c>')
    >>>('Ö, Ä', 'a@b.c')

    >>>formataddr(('Ö, Ä', 'a@b.c'))
    >>>'=?utf-8?q?=C3=96=2C_=C3=84?= <a@b.c>'

    >>>parseaddr('=?utf-8?q?=C3=96=2C_=C3=84?= <a@b.c>')
    >>>('=?utf-8?q?=C3=96=2C_=C3=84?=', 'a@b.c')

related issue #1402

2 files changed, 16 insertions, 1 deletions

diff --git a/alot/commands/thread.py b/alot/commands/thread.py
index e3c15b2e..c4ece713 100644
--- a/alot/commands/thread.py
+++ b/alot/commands/thread.py
@@ -10,7 +10,7 @@ import subprocess
 import tempfile
 import email
 import email.policy
-from email.utils import getaddresses, parseaddr, formataddr
+from email.utils import getaddresses, parseaddr
 from email.message import Message
 
 import urwid
@@ -26,6 +26,7 @@ from .common import RetagPromptCommand
 from .envelope import SendCommand
 from ..completion import ContactsCompleter, PathCompleter
 from ..db.utils import decode_header
+from ..db.utils import formataddr
 from ..db.utils import extract_headers
 from ..db.utils import extract_body
 from ..db.envelope import Envelope
diff --git a/alot/db/utils.py b/alot/db/utils.py
index 75fc0178..63260b22 100644
--- a/alot/db/utils.py
+++ b/alot/db/utils.py
@@ -512,6 +512,20 @@ def extract_body(mail, types=None, field_key='copiousoutput'):
     return u'\n\n'.join(body_parts)
 
 
+def formataddr(pair):
+    """ this is the inverse of email.utils.parseaddr:
+    other than email.utils.formataddr, this
+    - *will not* re-encode unicode strings, and
+    - *will* re-introduce quotes around real names containing commas
+    """
+    name, address = pair
+    if not name:
+        return address
+    elif ',' in name:
+        name = "\"" + name + "\""
+    return "{0} <{1}>".format(name, address)
+
+
 def decode_header(header, normalize=False):
     """
     decode a header value to a unicode string