Fix: parsing excel with chartsheet & Clamp begin to a minimum of 0 to prevent negative indexing (#10819)

### What problem does this PR solve?

Fix: parsing excel with chartsheet #10815

Fix: Clamp begin to a minimum of 0 to prevent negative indexing #10804
### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

rag/app/table.py

@@ -15,6 +15,7 @@
 #
 
 import copy
+import logging
 import re
 from io import BytesIO
 from xpinyin import Pinyin
@@ -44,7 +45,11 @@ class Excel(ExcelParser):
         rn = 0
         for sheetname in wb.sheetnames:
             ws = wb[sheetname]
-            rows = list(ws.rows)
+            try:
+                rows = list(ws.rows)
+            except Exception as e:
+                logging.warning(f"Skip sheet '{sheetname}' due to rows access error: {e}")
+                continue
             if not rows:
                 continue
             headers, header_rows = self._parse_headers(ws, rows)

rag/nlp/search.py

@@ -395,7 +395,9 @@ class Dealer:
                 tsim = sim
                 vsim = sim
         # Already paginated in search function
-        begin = ((page % (RERANK_LIMIT//page_size)) - 1) * page_size
+        max_pages = RERANK_LIMIT // page_size
+        page_index = (page % max_pages) - 1
+        begin = max(page_index * page_size, 0)
         sim = sim[begin : begin + page_size]
         sim_np = np.array(sim)
         idx = np.argsort(sim_np * -1)