我们正在尝试向每个我们发现可疑的电子邮件添加警告，但是一旦我们这样做了 - 并非所有电子邮件在更改后都按预期显示： - 在某些电子邮件中，我们破坏了样式并且消息的显示方式不同，而在其他电子邮件上我们在电子邮件顶部看到警告（类似于Google警告）。
对于在电子邮件的HTML部分添加“前缀”警告的操作，是否有任何最佳做法？做什么/不做？什么都有帮助！
这是一个片段：
def replace_body(self, email_instance, message_id, **kwargs):
def _generate_html_part_from_plain(_part):
_plain_text_body = _part.get_payload(decode=True)
_content_charset = _part.get_content_charset()
_artificial_html_body = '<div dir="ltr">{}</div>'.format(_plain_text_body.replace('\r\n', '<br>'))
_html_part = MIMEText(_artificial_html_body, 'html', _content_charset)
return _content_charset, _html_part
body_prefix = self.generate_prefix(message_id, email_instance, kwargs)
if not body_prefix:
log('prefix is empty, no need to update body (message={message_id})')
return True
if email_instance.is_multipart():
payload = email_instance.get_payload()
for part in payload:
if part.get_content_subtype() == 'html':
self.log.debug('email is \'multipart\' - attaching HTML part with warning (message={})'
.format(message_id))
prefixed_part = self.attach_email_prefix(body_prefix, part, 'html', part.get_content_charset())
payload.remove(part)
payload.append(prefixed_part)
break
# when no html part present
else:
for part in payload:
if part.get_content_subtype() == 'plain':
self.log.debug('email is \'multipart\', but no \'html\' part found: '
'generating and attaching HTML part with warning (message={})'
.format(message_id))
content_charset, html_part = _generate_html_part_from_plain(part)
prefixed_part = self.attach_email_prefix(body_prefix, html_part, 'html', content_charset)
top_content_subtype = email_instance.get_content_subtype()
if top_content_subtype != 'alternative':
self.log.debug('email\'s top-content-subtype is {}, generating alternative part to hold'
'\'plain\' and \'html\' parts, and attaching to email (message={})'
.format(top_content_subtype, message_id))
alternative_part = MIMEMultipart('alternative')
new_plain_part = MIMEText(part.get_payload(decode=True), 'plain', content_charset)
alternative_part.set_payload([new_plain_part, prefixed_part])
payload.remove(part)
payload.append(alternative_part)
else:
payload.append(prefixed_part)
break
email_instance.set_payload(payload)
elif email_instance.get_content_subtype() == 'plain':
self.log.debug('email is \'text/plain\', attaching artificial HTML part with warning (message={})'
.format(message_id))
# plain_part = deepcopy(email_instance)
content_charset, html_part = _generate_html_part_from_plain(email_instance)
prefixed_part = self.attach_email_prefix(body_prefix, html_part, 'html', content_charset)
email_instance.replace_header('Content-Type', 'multipart/alternative')
new_plain_part = MIMEText(email_instance.get_payload(decode=True), 'plain', content_charset)
email_instance.set_payload([new_plain_part, prefixed_part])
# email_instance.attach(html_part)
else:
self.log.warning('failed to attach HTML warning (message={}, top-content-type={})'
.format(message_id, email_instance.get_content_type()))
log('prefix attached to message successfully (message={message_id})')
return True
def attach_email_prefix(self, prefix, email_instance, subtype='html', charset='us-ascii'):
def attach_to_text(_part):
sep = {'html': '<br>', 'text': '\r\n'}
_part_payload = _part.get_payload(decode=True)
if not isinstance(_part_payload, str):
self.log.debug(
'skipping prefix attaching: Content payload\'s type is not str: {}'.format(_part_payload))
return _part
_part.set_payload('{}{}{}'.format(prefix, sep[subtype], _part_payload), charset)
return _part
if email_instance.get_content_subtype() == subtype:
return attach_to_text(email_instance)