From 6f0277db52d005420480abb0702d421525d6ea8b Mon Sep 17 00:00:00 2001
From: Timothy Jaeryang Baek <tim@openwebui.com>
Date: Mon, 1 Jun 2026 09:53:04 -0700
Subject: [PATCH] refac

---
 backend/open_webui/retrieval/loaders/main.py | 28 +++++++++++++++++++-
 backend/open_webui/routers/files.py          | 16 ++++++++---
 2 files changed, 40 insertions(+), 4 deletions(-)

diff --git a/backend/open_webui/retrieval/loaders/main.py b/backend/open_webui/retrieval/loaders/main.py
index 436d9a0acd..ede890793b 100644
--- a/backend/open_webui/retrieval/loaders/main.py
+++ b/backend/open_webui/retrieval/loaders/main.py
@@ -233,7 +233,33 @@ class Loader:
 
     def load(self, filename: str, file_content_type: str, file_path: str) -> list[Document]:
         loader = self._get_loader(filename, file_content_type, file_path)
-        docs = loader.load()
+
+        try:
+            docs = loader.load()
+        except (UnicodeDecodeError, RuntimeError, TimeoutError) as e:
+            # Only retry with latin-1 for text-encoding loaders (TextLoader,
+            # CSVLoader).  Binary format loaders (PDF, DOCX, PPTX, …) can
+            # raise RuntimeError for unrelated reasons; retrying those as
+            # plain text would produce garbage.
+            if not isinstance(loader, (TextLoader, CSVLoader)):
+                raise
+
+            # TextLoader/CSVLoader with autodetect_encoding=True can fail when:
+            # - chardet times out (5 s hardcoded in langchain)
+            # - chardet returns a wrong/low-confidence encoding
+            # - the file contains non-UTF-8 bytes (Latin-1, Windows-1252, …)
+            #
+            # Latin-1 is a safe last resort: every byte 0x00–0xFF is valid,
+            # and ftfy.fix_text() (applied below) repairs most mojibake that
+            # results from treating Windows-1252 content as Latin-1.
+            log.warning(
+                "Primary loader failed for %s (%s), retrying with latin-1 encoding: %s",
+                filename,
+                type(e).__name__,
+                e,
+            )
+            fallback_loader = TextLoader(file_path, encoding="latin-1")
+            docs = fallback_loader.load()
 
         return [Document(page_content=ftfy.fix_text(doc.page_content), metadata=doc.metadata) for doc in docs]
 
diff --git a/backend/open_webui/routers/files.py b/backend/open_webui/routers/files.py
index 31157dd803..3e036613d4 100644
--- a/backend/open_webui/routers/files.py
+++ b/backend/open_webui/routers/files.py
@@ -61,7 +61,11 @@ from open_webui.utils.access_control.files import has_access_to_file
 
 
 def _is_text_file(file_path: str, chunk_size: int = 8192) -> bool:
-    """Check if a file is likely a text file by reading a chunk and validating UTF-8.
+    """Check if a file is likely a text file by reading a chunk and decoding it.
+
+    Tries UTF-8 first, then falls back to Latin-1 (which accepts every byte
+    in 0x00–0xFF) so that legacy-encoded files from Windows environments are
+    not misclassified as binary.
 
     This catches files whose extensions are mis-mapped by mimetypes/browsers
     (e.g. TypeScript .ts → video/mp2t) without maintaining an extension whitelist.
@@ -75,9 +79,15 @@ def _is_text_file(file_path: str, chunk_size: int = 8192) -> bool:
         # Null bytes are a strong indicator of binary content
         if b'\x00' in chunk:
             return False
-        chunk.decode('utf-8')
+        try:
+            chunk.decode('utf-8')
+        except UnicodeDecodeError:
+            # Latin-1 always succeeds (every byte is valid), so this
+            # effectively just means "the file has no null bytes and is
+            # therefore likely text, even if not valid UTF-8".
+            chunk.decode('latin-1')
         return True
-    except (UnicodeDecodeError, Exception):
+    except Exception:
         return False