Fix:enhance delimiters in markdown parser (#10896)

### What problem does this PR solve?
issue:
[#10890](https://github.com/infiniflow/ragflow/issues/10890)
change：
enhance delimiters in markdown parser
### Type of change

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

deepdoc/parser/markdown_parser.py

@@ -117,11 +117,24 @@ class MarkdownElementExtractor:
         self.markdown_content = markdown_content
         self.lines = markdown_content.split("\n")
 
-    def extract_elements(self):
+    def get_delimiters(self,delimiters):
+        toks = re.findall(r"`([^`]+)`", delimiters)
+        toks = sorted(set(toks), key=lambda x: -len(x))
+        return "|".join(re.escape(t) for t in toks if t)
+    
+    def extract_elements(self,delimiter=None):
         """Extract individual elements (headers, code blocks, lists, etc.)"""
         sections = []
 
         i = 0
+        dels=""
+        if delimiter:
+            dels = self.get_delimiters(delimiter)
+        if len(dels) > 0:
+            text = "\n".join(self.lines)
+            parts = re.split(dels, text)
+            sections = [p.strip() for p in parts if p and p.strip()]
+            return sections
         while i < len(self.lines):
             line = self.lines[i]
 

rag/app/naive.py

@@ -397,7 +397,7 @@ class Markdown(MarkdownParser):
 
         return images if images else None
 
-    def __call__(self, filename, binary=None, separate_tables=True):
+    def __call__(self, filename, binary=None, separate_tables=True,delimiter=None):
         if binary:
             encoding = find_codec(binary)
             txt = binary.decode(encoding, errors="ignore")
@@ -408,7 +408,7 @@ class Markdown(MarkdownParser):
         remainder, tables = self.extract_tables_and_remainder(f'{txt}\n', separate_tables=separate_tables)
 
         extractor = MarkdownElementExtractor(txt)
-        element_sections = extractor.extract_elements()
+        element_sections = extractor.extract_elements(delimiter)
         sections = [(element, "") for element in element_sections]
 
         tbls = []
@@ -600,7 +600,7 @@ def chunk(filename, binary=None, from_page=0, to_page=100000,
     elif re.search(r"\.(md|markdown)$", filename, re.IGNORECASE):
         callback(0.1, "Start to parse.")
         markdown_parser = Markdown(int(parser_config.get("chunk_token_num", 128)))
-        sections, tables = markdown_parser(filename, binary, separate_tables=False)
+        sections, tables = markdown_parser(filename, binary, separate_tables=False,delimiter=parser_config.get("delimiter", "\n!?;。；！？"))
 
         try:
             vision_model = LLMBundle(kwargs["tenant_id"], LLMType.IMAGE2TEXT)