fix: support extended content-disposition filenames

packages/markitdown/src/markitdown/_markitdown.py

@@ -6,6 +6,8 @@
 import traceback
 import io
 from dataclasses import dataclass
+from email.message import Message
+from email.utils import collapse_rfc2231_value
 from importlib.metadata import entry_points
 from typing import Any, List, Dict, Optional, Union, BinaryIO
 from pathlib import Path
@@ -44,13 +46,31 @@
 
 from ._base_converter import DocumentConverter, DocumentConverterResult
 
+
 from ._exceptions import (
     FileConversionException,
     UnsupportedFormatException,
     FailedConversionAttempt,
 )
 
 
+def _get_content_disposition_filename(content_disposition: str) -> Optional[str]:
+    message = Message()
+    message["content-disposition"] = content_disposition
+
+    fallback_filename: Optional[str] = None
+    extended_filename: Optional[str] = None
+    for key, value in message.get_params(header="content-disposition", unquote=True):
+        if key != "filename":
+            continue
+        if isinstance(value, tuple):
+            extended_filename = collapse_rfc2231_value(value)
+        elif fallback_filename is None:
+            fallback_filename = value
+
+    return extended_filename or fallback_filename
+
+
 # Lower priority values are tried first.
 PRIORITY_SPECIFIC_FILE_FORMAT = (
     0.0  # e.g., .docx, .pdf, .xlsx, Or specific pages, e.g., wikipedia
@@ -512,9 +532,10 @@ def convert_response(
         filename: Optional[str] = None
         extension: Optional[str] = None
         if "content-disposition" in response.headers:
-            m = re.search(r"filename=([^;]+)", response.headers["content-disposition"])
-            if m:
-                filename = m.group(1).strip("\"'")
+            filename = _get_content_disposition_filename(
+                response.headers["content-disposition"]
+            )
+            if filename is not None:
                 _, _extension = os.path.splitext(filename)
                 if len(_extension) > 0:
                     extension = _extension

packages/markitdown/tests/test_module_misc.py

@@ -288,6 +288,45 @@ def test_input_as_strings() -> None:
     assert "# Test" in result.text_content
 
 
+def _mock_response(content_disposition: str) -> MagicMock:
+    response = MagicMock()
+    response.headers = {"content-disposition": content_disposition}
+    response.url = "https://example.com/download"
+    response.iter_content.return_value = [b"name,value\nalpha,beta\n"]
+    response.raise_for_status.return_value = None
+    return response
+
+
+def test_convert_response_uses_rfc5987_content_disposition_filename() -> None:
+    markitdown = MarkItDown()
+    result = markitdown.convert_response(
+        _mock_response("attachment; filename*=UTF-8''data.csv")
+    )
+
+    assert result.markdown == "\n".join(
+        [
+            "| name | value |",
+            "| --- | --- |",
+            "| alpha | beta |",
+        ]
+    )
+
+
+def test_convert_response_prefers_extended_content_disposition_filename() -> None:
+    markitdown = MarkItDown()
+    result = markitdown.convert_response(
+        _mock_response("attachment; filename=fallback.txt; filename*=UTF-8''data.csv")
+    )
+
+    assert result.markdown == "\n".join(
+        [
+            "| name | value |",
+            "| --- | --- |",
+            "| alpha | beta |",
+        ]
+    )
+
+
 def test_deeply_nested_html_fallback() -> None:
     """Large, deeply nested HTML should fall back to plain-text extraction
     instead of silently returning unconverted HTML (issue #1636).