diff --git a/backend/app/text_extract.py b/backend/app/text_extract.py
new file mode 100644
index 0000000..7664ca8
--- /dev/null
+++ b/backend/app/text_extract.py
@@ -0,0 +1,38 @@
+import re
+from html.parser import HTMLParser
+
+
+class _HTMLTextExtractor(HTMLParser):
+ def __init__(self):
+ super().__init__()
+ self._chunks = []
+
+ def handle_data(self, data):
+ self._chunks.append(data)
+
+ def get_text(self):
+ return "".join(self._chunks)
+
+
+def html_to_text(text: str) -> str:
+ parser = _HTMLTextExtractor()
+ parser.feed(text)
+ parser.close()
+ raw = parser.get_text()
+ return re.sub(r"\s+", " ", raw).strip()
+
+
+def markdown_to_text(text: str) -> str:
+ result = text
+ result = re.sub(r"```.*?```", " ", result, flags=re.DOTALL)
+ result = re.sub(r"`([^`]*)`", r"\1", result)
+ result = re.sub(r"!\[([^\]]*)\]\([^)]*\)", r"\1", result)
+ result = re.sub(r"\[([^\]]*)\]\([^)]*\)", r"\1", result)
+ result = re.sub(r"^\s{0,3}#{1,6}\s*", "", result, flags=re.MULTILINE)
+ result = re.sub(r"(\*\*\*|___)(.+?)\1", r"\2", result)
+ result = re.sub(r"(\*\*|__)(.+?)\1", r"\2", result)
+ result = re.sub(r"(\*|_)(.+?)\1", r"\2", result)
+ result = re.sub(r"^\s*([-*+]|\d+\.)\s+", "", result, flags=re.MULTILINE)
+ result = re.sub(r"^\s*>\s*", "", result, flags=re.MULTILINE)
+ result = re.sub(r"\s+", " ", result).strip()
+ return result
diff --git a/backend/tests/test_text_extract.py b/backend/tests/test_text_extract.py
new file mode 100644
index 0000000..6c7cce6
--- /dev/null
+++ b/backend/tests/test_text_extract.py
@@ -0,0 +1,77 @@
+from app.text_extract import html_to_text, markdown_to_text
+
+
+def test_html_to_text_strips_tags():
+ html = """
+
+
+ 架构设计
+ DocHub 是一个基于 MinIO 的文档管理系统。
+
+
+
+ """
+ result = html_to_text(html)
+ assert "架构设计" in result
+ assert "DocHub 是一个基于 MinIO 的文档管理系统。" in result
+ assert "浏览文档" in result
+ assert "" not in result
+ assert "" not in result
+
+
+def test_html_to_text_collapses_whitespace():
+ html = "第一段
\n\n\n第二段
"
+ result = html_to_text(html)
+ assert result == "第一段 第二段"
+
+
+def test_markdown_to_text_strips_headers_and_emphasis():
+ markdown = """# 架构设计
+
+## 背景
+
+DocHub 是一个 **基于 MinIO** 的 _文档管理系统_，支持全文检索。
+"""
+ result = markdown_to_text(markdown)
+ assert "#" not in result
+ assert "**" not in result
+ assert "_" not in result
+ assert "架构设计" in result
+ assert "背景" in result
+ assert "基于 MinIO" in result
+ assert "文档管理系统" in result
+
+
+def test_markdown_to_text_strips_links_and_list_markers():
+ markdown = """## 功能列表
+
+- 浏览 [MinIO](https://min.io) 中存储的文档
+- 支持 [Meilisearch](https://www.meilisearch.com) 全文检索
+1. 在线编辑并保存
+"""
+ result = markdown_to_text(markdown)
+ assert "[" not in result
+ assert "](" not in result
+ assert "浏览 MinIO 中存储的文档" in result
+ assert "支持 Meilisearch 全文检索" in result
+ assert "在线编辑并保存" in result
+
+
+def test_markdown_to_text_strips_code_fences_and_inline_code():
+ markdown = """使用 `pip install -r requirements.txt` 安装依赖。
+
+```python
+def hello():
+ return "world"
+```
+
+安装完成后启动服务。
+"""
+ result = markdown_to_text(markdown)
+ assert "```" not in result
+ assert "def hello" not in result
+ assert "使用 pip install -r requirements.txt 安装依赖。" in result
+ assert "安装完成后启动服务。" in result