Extract delimiter support, add unit tests

Also: fix recursive call to get_cert_for_email.

gpg-mailgate.py

@@ -315,26 +315,29 @@ def smime_encrypt( raw_message, recipients ):
 def get_cert_for_email( to_addr, cert_path ):
 	global LOG
 
+	insensitive = conf.config_item_equals('default', 'mail_case_insensitive', 'yes')
+
 	files_in_directory = os.listdir(cert_path)
 	for filename in files_in_directory:
 		file_path = os.path.join(cert_path, filename)
 		if not os.path.isfile(file_path):
 			continue
 
-		if conf.config_item_equals('default', 'mail_case_insensitive', 'yes'):
-			if filename.lower() == to_addr:
+		if insensitive:
+			if filename.casefold() == to_addr:
 				return (file_path, to_addr)
 		else:
 			if filename == to_addr:
 				return (file_path, to_addr)
-	# support foo+ignore@bar.com -> foo@bar.com
-	multi_email = re.match('^([^\+]+)\+([^@]+)@(.*)$', to_addr)
-	if multi_email:
-		fixed_up_email = "%s@%s" % (multi_email.group(1), multi_email.group(3))
-		LOG.debug("Multi-email %s converted to %s" % (to_addr, fixed_up_email))
-		return get_cert_for_email(fixed_up_email)
 
-	return None
+	# support foo+ignore@bar.com -> foo@bar.com
+	(fixed_up_email, topic) = text.parse_delimiter(to_addr)
+	if topic is None:
+		# delimiter not used
+		return None
+	else:
+		LOG.debug(f"Looking up certificate for {fixed_up_email} after parsing {to_addr}")
+		return get_cert_for_email(fixed_up_email, cert_path)
 
 def sanitize_case_sense( address ):
 	if conf.config_item_equals('default', 'mail_case_insensitive', 'yes'):

lacre/text.py

@@ -1,4 +1,5 @@
 import sys
+import re
 
 # The standard way to encode line-ending in email:
 EOL = "\r\n"
@@ -22,6 +23,13 @@ def parse_content_type(content_type):
 	else:
 		return (ctype, sys.getdefaultencoding())
 
+def parse_delimiter(address):
+	withdelim = re.match('^([^\+]+)\+([^@]+)@(.*)$', address)
+	if withdelim:
+		return (withdelim.group(1) + '@' + withdelim.group(3), withdelim.group(2))
+	else:
+		return (address, None)
+
 def is_pgp_inline(payload):
 	"""Finds out if the payload (bytes) contains PGP/INLINE markers."""
 	return PGP_INLINE_BEGIN in payload and PGP_INLINE_END in payload

test/test_lacre_text.py

@@ -23,3 +23,15 @@ class LacreTextTest(unittest.TestCase):
 		(mtype, mcharset) = lacre.text.parse_content_type('text/plain; charset="UTF-8"; some-param="Some Value"')
 		self.assertEqual(mtype, 'text/plain')
 		self.assertEqual(mcharset, '"UTF-8"')
+
+	def test_parse_email_without_delimiter(self):
+		addr = "Some.Name@example.com"
+		(addr2, topic) = lacre.text.parse_delimiter(addr)
+		self.assertEqual(addr2, "Some.Name@example.com")
+		self.assertEqual(topic, None)
+
+	def test_parse_email_with_delimiter(self):
+		addr = "Some.Name+some-topic@example.com"
+		(addr2, topic) = lacre.text.parse_delimiter(addr)
+		self.assertEqual(addr2, "Some.Name@example.com")
+		self.assertEqual(topic, "some-topic")