From 26d664f277a330bb63ee03820d8c2f6f1bbf951a Mon Sep 17 00:00:00 2001
From: lorenpike <55057781+lorenpike@users.noreply.github.com>
Date: Fri, 9 Feb 2024 16:45:33 -0500
Subject: [PATCH] Check if `Message.get_params` return 3-`tuple` instead of
 `str` on `parse_options_header` (#79)

* Fixing issue #78

* Added test for parse_options_header

* Added a comment clarifying a condition in parse_options_header

* Fixed a typo

---------

Co-authored-by: lorenpike <noahe@metrized.com>
---
 multipart/multipart.py  | 5 +++++
 tests/test_multipart.py | 5 +++++
 2 files changed, 10 insertions(+)

diff --git a/multipart/multipart.py b/multipart/multipart.py
index 6ec1364..73910da 100644
--- a/multipart/multipart.py
+++ b/multipart/multipart.py
@@ -99,6 +99,11 @@ def parse_options_header(value: Union[str, bytes]) -> Tuple[bytes, Dict[bytes, b
     options = {}
     for param in params:
         key, value = param
+        # If the value returned from get_params() is a 3-tuple, the last
+        # element corresponds to the value.
+        # See: https://docs.python.org/3/library/email.compat32-message.html
+        if isinstance(value, tuple):
+            value = value[-1]
         # If the value is a filename, we need to fix a bug on IE6 that sends
         # the full file path instead of the filename.
         if key == 'filename':
diff --git a/tests/test_multipart.py b/tests/test_multipart.py
index 2ceecab..5cfacf4 100644
--- a/tests/test_multipart.py
+++ b/tests/test_multipart.py
@@ -276,6 +276,11 @@ def test_redos_attack_header(self):
         # If vulnerable, this test wouldn't finish, the line above would hang
         self.assertIn(b'"\\', p[b'!'])
 
+    def test_handles_rfc_2231(self):
+        t, p = parse_options_header(b'text/plain; param*=us-ascii\'en-us\'encoded%20message')
+
+        self.assertEqual(p[b'param'], b'encoded message')
+
 
 class TestBaseParser(unittest.TestCase):
     def setUp(self):