[IMP] ir_mail_server: IDNA and SMTPUTF8 capabilities

It has been a recurrent request from customers to be able to send email
messages to email addresses containing non-ascii characters. [IDNA] is a
domain extension to allow unicode characters in domain names. [SMTPUTF8]
is a SMTP extension to allow unicode in any header.

IDNA defines the [punycode] encoding which translates unicode to an
ascii representation. This encoding MUST be used to encode domains.

SMTPUTF8 is an SMTP extension that allow utf-8 in all headers on the
envelope.

[IDNA] https://tools.ietf.org/html/rfc5890
[SMTPUTF8] https://tools.ietf.org/html/rfc6531
[punycode] https://tools.ietf.org/html/rfc3492

Task: 2116928
opw-2229906
opw-2248251

closes odoo/odoo#47709

Signed-off-by: Raphael Collet (rco) <rco@openerp.com>

1 files changed, 20 insertions, 12 deletions

diff --git a/odoo/tools/mail.py b/odoo/tools/mail.py
index c1a14e964fc..1a3e9d80b9f 100644
--- a/odoo/tools/mail.py
+++ b/odoo/tools/mail.py
@@ -14,6 +14,7 @@ import time
 from email.utils import getaddresses
 from lxml import etree
 from werkzeug import urls
+import idna
 
 import odoo
 from odoo.loglevels import ustr
@@ -546,13 +547,15 @@ def decode_message_header(message, header, separator=' '):
 def formataddr(pair, charset='utf-8'):
     """Pretty format a 2-tuple of the form (realname, email_address).
 
-    Set the charset to ascii to get a RFC-2822 compliant email.
-
-    The email address is considered valid and is left unmodified.
-
     If the first element of pair is falsy then only the email address
     is returned.
 
+    Set the charset to ascii to get a RFC-2822 compliant email. The
+    realname will be base64 encoded (if necessary) and the domain part
+    of the email will be punycode encoded (if necessary). The local part
+    is left unchanged thus require the SMTPUTF8 extension when there are
+    non-ascii characters.
+
     >>> formataddr(('John Doe', 'johndoe@example.com'))
     '"John Doe" <johndoe@example.com>'
 
@@ -560,21 +563,26 @@ def formataddr(pair, charset='utf-8'):
     'johndoe@example.com'
     """
     name, address = pair
-    address.encode('ascii')
+    local, _, domain = address.rpartition('@')
+
+    try:
+        domain.encode(charset)
+    except UnicodeEncodeError:
+        # rfc5890 - Internationalized Domain Names for Applications (IDNA)
+        domain = idna.encode(domain).decode('ascii')
+
     if name:
         try:
             name.encode(charset)
         except UnicodeEncodeError:
             # charset mismatch, encode as utf-8/base64
             # rfc2047 - MIME Message Header Extensions for Non-ASCII Text
-            return "=?utf-8?b?{name}?= <{addr}>".format(
-                name=base64.b64encode(name.encode('utf-8')).decode('ascii'),
-                addr=address)
+            name = base64.b64encode(name.encode('utf-8')).decode('ascii')
+            return f"=?utf-8?b?{name}?= <{local}@{domain}>"
         else:
             # ascii name, escape it if needed
             # rfc2822 - Internet Message Format
             #   #section-3.4 - Address Specification
-            return '"{name}" <{addr}>'.format(
-                name=email_addr_escapes_re.sub(r'\\\g<0>', name),
-                addr=address)
-    return address
+            name = email_addr_escapes_re.sub(r'\\\g<0>', name)
+            return f'"{name}" <{local}@{domain}>'
+    return f"{local}@{domain}"