Fix: Handle NoneType error when processing documents without a file path

The document processing pipeline would crash with a TypeError when a document was submitted as raw text via the API, as the file_path attribute would be None. This change adds a check to handle the None case gracefully, preventing the crash and allowing text-based documents to be indexed correctly.

lightrag/lightrag.py

@@ -900,9 +900,15 @@ class LightRAG:
                 # Get first document's file path and total count for job name
                 first_doc_id, first_doc = next(iter(to_process_docs.items()))
                 first_doc_path = first_doc.file_path
-                path_prefix = first_doc_path[:20] + (
-                    "..." if len(first_doc_path) > 20 else ""
-                )
+
+                # Handle cases where first_doc_path is None
+                if first_doc_path:
+                    path_prefix = first_doc_path[:20] + (
+                        "..." if len(first_doc_path) > 20 else ""
+                    )
+                else:
+                    path_prefix = "unknown_source"
+
                 total_files = len(to_process_docs)
                 job_name = f"{path_prefix}[{total_files} files]"
                 pipeline_status["job_name"] = job_name