Fix the bug causing garbled text (#3640)

### What problem does this PR solve?

Fix the bug causing garbled text #3613

### Type of change

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

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>

api/apps/kb_app.py

                     message="Database error (Document removal)!")
             f2d = File2DocumentService.get_by_document_id(doc.id)
             FileService.filter_delete([File.source_type == FileSource.KNOWLEDGEBASE, File.id == f2d[0].file_id])
-            FileService.filter_delete([File.source_type == FileSource.KNOWLEDGEBASE, File.type == "folder", File.name == kbs[0].name])
             File2DocumentService.delete_by_document_id(doc.id)
-
+        FileService.filter_delete(
+            [File.source_type == FileSource.KNOWLEDGEBASE, File.type == "folder", File.name == kbs[0].name])
         if not KnowledgebaseService.delete_by_id(req["kb_id"]):
             return get_data_error_result(
                 message="Database error (Knowledgebase removal)!")

api/apps/sdk/dataset.py

                     File.id == f2d[0].file_id,
                 ]
             )
-            FileService.filter_delete(
-                [File.source_type == FileSource.KNOWLEDGEBASE, File.type == "folder", File.name == kbs[0].name])
             File2DocumentService.delete_by_document_id(doc.id)
+        FileService.filter_delete(
+            [File.source_type == FileSource.KNOWLEDGEBASE, File.type == "folder", File.name == kbs[0].name])
         if not KnowledgebaseService.delete_by_id(id):
             return get_error_data_result(message="Delete dataset error.(Database error)")
     return get_result(code=settings.RetCode.SUCCESS)

rag/nlp/__init__.py

 from PIL import Image
 import json
 
+import chardet
+
 all_codecs = [
     'utf-8', 'gb2312', 'gbk', 'utf_16', 'ascii', 'big5', 'big5hkscs',
     'cp037', 'cp273', 'cp424', 'cp437',
     'iso8859_14', 'iso8859_15', 'iso8859_16', 'johab', 'koi8_r', 'koi8_t', 'koi8_u',
     'kz1048', 'mac_cyrillic', 'mac_greek', 'mac_iceland', 'mac_latin2', 'mac_roman',
     'mac_turkish', 'ptcp154', 'shift_jis', 'shift_jis_2004', 'shift_jisx0213',
-    'utf_32', 'utf_32_be', 'utf_32_le''utf_16_be', 'utf_16_le', 'utf_7'
+    'utf_32', 'utf_32_be', 'utf_32_le', 'utf_16_be', 'utf_16_le', 'utf_7', 'windows-1250', 'windows-1251',
+    'windows-1252', 'windows-1253', 'windows-1254', 'windows-1255', 'windows-1256',
+    'windows-1257', 'windows-1258', 'latin-2'
 ]
 
 
 def find_codec(blob):
-    global all_codecs
+    detected = chardet.detect(blob[:1024])
+    if detected['confidence'] > 0.5:
+        return detected['encoding']
+
     for c in all_codecs:
         try:
             blob[:1024].decode(c)