diff -r 058bb3dc685f -r 0b59724cb3f2 cubicweb/mail.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cubicweb/mail.py	Sat Jan 16 13:48:51 2016 +0100
@@ -0,0 +1,154 @@
+# copyright 2003-2012 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
+# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
+#
+# This file is part of CubicWeb.
+#
+# CubicWeb is free software: you can redistribute it and/or modify it under the
+# terms of the GNU Lesser General Public License as published by the Free
+# Software Foundation, either version 2.1 of the License, or (at your option)
+# any later version.
+#
+# CubicWeb is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Lesser General Public License along
+# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.
+"""Common utilies to format / send emails."""
+
+__docformat__ = "restructuredtext en"
+
+from base64 import b64encode, b64decode
+from time import time
+from email.mime.multipart import MIMEMultipart
+from email.mime.text import MIMEText
+from email.mime.image import MIMEImage
+from email.header import Header
+from email.utils import formatdate
+from socket import gethostname
+
+from six import PY2, PY3, text_type
+
+
+def header(ustring):
+    if PY3:
+        return Header(ustring, 'utf-8')
+    return Header(ustring.encode('UTF-8'), 'UTF-8')
+
+def addrheader(uaddr, uname=None):
+    # even if an email address should be ascii, encode it using utf8 since
+    # automatic tests may generate non ascii email address
+    if PY2:
+        addr = uaddr.encode('UTF-8')
+    else:
+        addr = uaddr
+    if uname:
+        val = '%s <%s>' % (header(uname).encode(), addr)
+    else:
+        val = addr
+    assert isinstance(val, str)  # bytes in py2, ascii-encoded unicode in py3
+    return val
+
+
+def construct_message_id(appid, eid, withtimestamp=True):
+    if withtimestamp:
+        addrpart = 'eid=%s&timestamp=%.10f' % (eid, time())
+    else:
+        addrpart = 'eid=%s' % eid
+    # we don't want any equal sign nor trailing newlines
+    leftpart = b64encode(addrpart.encode('ascii'), b'.-').decode('ascii').rstrip().rstrip('=')
+    return '<%s@%s.%s>' % (leftpart, appid, gethostname())
+
+
+def parse_message_id(msgid, appid):
+    if msgid[0] == '<':
+        msgid = msgid[1:]
+    if msgid[-1] == '>':
+        msgid = msgid[:-1]
+    try:
+        values, qualif = msgid.split('@')
+        padding = len(values) % 4
+        values = b64decode(str(values + '='*padding), '.-').decode('ascii')
+        values = dict(v.split('=') for v in values.split('&'))
+        fromappid, host = qualif.split('.', 1)
+    except Exception:
+        return None
+    if appid != fromappid or host != gethostname():
+        return None
+    return values
+
+
+def format_mail(uinfo, to_addrs, content, subject="",
+                cc_addrs=(), msgid=None, references=(), config=None):
+    """Sends an Email to 'e_addr' with content 'content', and subject 'subject'
+
+    to_addrs and cc_addrs are expected to be a list of email address without
+    name
+    """
+    assert isinstance(content, text_type), repr(content)
+    msg = MIMEText(content.encode('UTF-8'), 'plain', 'UTF-8')
+    # safety: keep only the first newline
+    try:
+        subject = subject.splitlines()[0]
+        msg['Subject'] = header(subject)
+    except IndexError:
+        pass # no subject
+    if uinfo.get('email'):
+        email = uinfo['email']
+    elif config and config['sender-addr']:
+        email = text_type(config['sender-addr'])
+    else:
+        email = u''
+    if uinfo.get('name'):
+        name = uinfo['name']
+    elif config and config['sender-name']:
+        name = text_type(config['sender-name'])
+    else:
+        name = u''
+    msg['From'] = addrheader(email, name)
+    if config and config['sender-addr'] and config['sender-addr'] != email:
+        appaddr = addrheader(config['sender-addr'], config['sender-name'])
+        msg['Reply-to'] = '%s, %s' % (msg['From'], appaddr)
+    elif email:
+        msg['Reply-to'] = msg['From']
+    if config is not None:
+        msg['X-CW'] = config.appid
+    unique_addrs = lambda addrs: sorted(set(addr for addr in addrs if addr is not None))
+    msg['To'] = ', '.join(addrheader(addr) for addr in unique_addrs(to_addrs))
+    if cc_addrs:
+        msg['Cc'] = ', '.join(addrheader(addr) for addr in unique_addrs(cc_addrs))
+    if msgid:
+        msg['Message-id'] = msgid
+    if references:
+        msg['References'] = ', '.join(references)
+    msg['Date'] = formatdate()
+    return msg
+
+
+class HtmlEmail(MIMEMultipart):
+
+    def __init__(self, subject, textcontent, htmlcontent,
+                 sendermail=None, sendername=None, recipients=None, ccrecipients=None):
+        MIMEMultipart.__init__(self, 'related')
+        self['Subject'] = header(subject)
+        self.preamble = 'This is a multi-part message in MIME format.'
+        # Attach alternative text message
+        alternative = MIMEMultipart('alternative')
+        self.attach(alternative)
+        msgtext = MIMEText(textcontent.encode('UTF-8'), 'plain', 'UTF-8')
+        alternative.attach(msgtext)
+        # Attach html message
+        msghtml = MIMEText(htmlcontent.encode('UTF-8'), 'html', 'UTF-8')
+        alternative.attach(msghtml)
+        if sendermail or sendername:
+            self['From'] = addrheader(sendermail, sendername)
+        if recipients:
+            self['To'] = ', '.join(addrheader(addr) for addr in recipients if addr is not None)
+        if ccrecipients:
+            self['Cc'] = ', '.join(addrheader(addr) for addr in ccrecipients if addr is not None)
+
+    def attach_image(self, data, htmlId):
+        image = MIMEImage(data)
+        image.add_header('Content-ID', '<%s>' % htmlId)
+        self.attach(image)