From ec4607292b9254b52fd60d35331831b05be3d554 Mon Sep 17 00:00:00 2001
From: Lucas Ma <7184042+pony-maggie@users.noreply.github.com>
Date: Mon, 15 Jun 2026 08:27:01 +0800
Subject: [PATCH] fix: handle URI schemes case-insensitively

---
 .../markitdown/src/markitdown/_markitdown.py  | 15 ++++++---------
 .../markitdown/src/markitdown/_uri_utils.py   |  2 +-
 packages/markitdown/tests/test_module_misc.py | 19 +++++++++++++++++++
 3 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/packages/markitdown/src/markitdown/_markitdown.py b/packages/markitdown/src/markitdown/_markitdown.py
index f6aa4df0e..ab9528534 100644
--- a/packages/markitdown/src/markitdown/_markitdown.py
+++ b/packages/markitdown/src/markitdown/_markitdown.py
@@ -288,12 +288,8 @@ def convert(
 
         # Local path or url
         if isinstance(source, str):
-            if (
-                source.startswith("http:")
-                or source.startswith("https:")
-                or source.startswith("file:")
-                or source.startswith("data:")
-            ):
+            scheme = urlparse(source.strip()).scheme.lower()
+            if scheme in ("http", "https", "file", "data"):
                 # Rename the url argument to mock_url
                 # (Deprecated -- use stream_info)
                 _kwargs = {k: v for k, v in kwargs.items()}
@@ -437,9 +433,10 @@ def convert_uri(
         **kwargs: Any,
     ) -> DocumentConverterResult:
         uri = uri.strip()
+        scheme = urlparse(uri).scheme.lower()
 
         # File URIs
-        if uri.startswith("file:"):
+        if scheme == "file":
             netloc, path = file_uri_to_path(uri)
             if netloc and netloc != "localhost":
                 raise ValueError(
@@ -453,7 +450,7 @@ def convert_uri(
                 **kwargs,
             )
         # Data URIs
-        elif uri.startswith("data:"):
+        elif scheme == "data":
             mimetype, attributes, data = parse_data_uri(uri)
 
             base_guess = StreamInfo(
@@ -471,7 +468,7 @@ def convert_uri(
                 **kwargs,
             )
         # HTTP/HTTPS URIs
-        elif uri.startswith("http:") or uri.startswith("https:"):
+        elif scheme in ("http", "https"):
             response = self._requests_session.get(uri, stream=True)
             response.raise_for_status()
             return self.convert_response(
diff --git a/packages/markitdown/src/markitdown/_uri_utils.py b/packages/markitdown/src/markitdown/_uri_utils.py
index 603da63e9..861a83116 100644
--- a/packages/markitdown/src/markitdown/_uri_utils.py
+++ b/packages/markitdown/src/markitdown/_uri_utils.py
@@ -17,7 +17,7 @@ def file_uri_to_path(file_uri: str) -> Tuple[str | None, str]:
 
 
 def parse_data_uri(uri: str) -> Tuple[str | None, Dict[str, str], bytes]:
-    if not uri.startswith("data:"):
+    if not uri.lower().startswith("data:"):
         raise ValueError("Not a data URI")
 
     header, _, data = uri.partition(",")
diff --git a/packages/markitdown/tests/test_module_misc.py b/packages/markitdown/tests/test_module_misc.py
index 4d62e4919..aba9e81e8 100644
--- a/packages/markitdown/tests/test_module_misc.py
+++ b/packages/markitdown/tests/test_module_misc.py
@@ -239,6 +239,25 @@ def test_file_uris() -> None:
     assert netloc == "localhost"
     assert path == "/path/to/file.txt"
 
+    # URI schemes are case-insensitive
+    file_uri = "FILE:///path/to/file.txt"
+    netloc, path = file_uri_to_path(file_uri)
+    assert netloc is None
+    assert path == "/path/to/file.txt"
+
+
+def test_convert_case_insensitive_uri_schemes(tmp_path) -> None:
+    markitdown = MarkItDown()
+
+    data_result = markitdown.convert("DATA:text/plain;base64,SGVsbG8sIFdvcmxkIQ==")
+    assert data_result.markdown == "Hello, World!"
+
+    text_file = tmp_path / "hello.txt"
+    text_file.write_text("Hello from file", encoding="utf-8")
+
+    file_result = markitdown.convert(text_file.as_uri().replace("file:", "FILE:", 1))
+    assert file_result.markdown == "Hello from file"
+
     # Test file URI with query parameters
     file_uri = "file:///path/to/file.txt?param=value"
     netloc, path = file_uri_to_path(file_uri)