Don't warn when CRLF is found after last boundary (#193)

Author: Kludex

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## 0.0.19 (2024-11-30)
+
+* Don't warn when CRLF is found after last boundary on `MultipartParser` [#193](https://github.com/Kludex/python-multipart/pull/193).
+
 ## 0.0.18 (2024-11-28)
 
 * Hard break if found data after last boundary on `MultipartParser` [#189](https://github.com/Kludex/python-multipart/pull/189).

python_multipart/__init__.py

@@ -2,7 +2,7 @@
 __author__ = "Andrew Dunham"
 __license__ = "Apache"
 __copyright__ = "Copyright (c) 2012-2013, Andrew Dunham"
-__version__ = "0.0.18"
+__version__ = "0.0.19"
 
 from .multipart import (
     BaseParser,

python_multipart/multipart.py

@@ -1397,6 +1397,10 @@ def data_callback(name: CallbackName, end_i: int, remaining: bool = False) -> No
                     i -= 1
 
             elif state == MultipartState.END:
+                # Don't do anything if chunk ends with CRLF.
+                if c == CR and i + 1 < length and data[i + 1] == LF:
+                    i += 2
+                    continue
                 # Skip data after the last boundary.
                 self.logger.warning("Skipping data after last boundary")
                 i = length

scripts/check

@@ -6,5 +6,5 @@ SOURCE_FILES="python_multipart multipart tests"
 
 uvx ruff format --check --diff $SOURCE_FILES
 uvx ruff check $SOURCE_FILES
-uvx --with types-PyYAML mypy $SOURCE_FILES
+uv run mypy $SOURCE_FILES
 uvx check-sdist

tests/test_multipart.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import logging
 import os
 import random
 import sys
@@ -9,6 +10,7 @@
 from typing import TYPE_CHECKING, cast
 from unittest.mock import Mock
 
+import pytest
 import yaml
 
 from python_multipart.decoders import Base64Decoder, QuotedPrintableDecoder
@@ -1248,6 +1250,30 @@ def on_file(f: FileProtocol) -> None:
         f = FormParser("multipart/form-data", on_field=Mock(), on_file=on_file, boundary="boundary")
         f.write(data.encode("latin-1"))
 
+    @pytest.fixture(autouse=True)
+    def inject_fixtures(self, caplog: pytest.LogCaptureFixture) -> None:
+        self._caplog = caplog
+
+    def test_multipart_parser_data_end_with_crlf_without_warnings(self) -> None:
+        """This test makes sure that the parser does not handle when the data ends with a CRLF."""
+        data = (
+            "--boundary\r\n"
+            'Content-Disposition: form-data; name="file"; filename="filename.txt"\r\n'
+            "Content-Type: text/plain\r\n\r\n"
+            "hello\r\n"
+            "--boundary--\r\n"
+        )
+
+        files: list[File] = []
+
+        def on_file(f: FileProtocol) -> None:
+            files.append(cast(File, f))
+
+        f = FormParser("multipart/form-data", on_field=Mock(), on_file=on_file, boundary="boundary")
+        with self._caplog.at_level(logging.WARNING):
+            f.write(data.encode("latin-1"))
+            assert len(self._caplog.records) == 0
+
     def test_max_size_multipart(self) -> None:
         # Load test data.
         test_file = "single_field_single_file.http"