用 marknb 替换 Python markdown，并添加一键安装与升级脚本。

部署时通过 install.sh 自动编译 marknb；日常更新用 upgrade.sh 拉代码并重编译。

Co-authored-by: Cursor <cursoragent@cursor.com>

blog.py

@@ -2,8 +2,8 @@
 单文件博客：FastAPI + SQLite + Jinja2，Markdown 预渲染为 HTML。
 
 安装依赖:
-  pip install -r requirements.txt
-  # 或: pip install fastapi "uvicorn[standard]" jinja2 python-multipart markdown
+  bash scripts/install.sh
+  # 或手动: 编译 vendor/marknb/libmarknb.so 后 pip install -r requirements.txt
 
 运行:
   python blog.py
@@ -26,18 +26,18 @@
 from __future__ import annotations
 
 import asyncio
+import ctypes
 import hashlib
 import os
 import re
 import secrets
 import sqlite3
+import sys
 from contextlib import contextmanager
 from datetime import datetime, timezone
 from pathlib import Path
 from typing import Any, Optional
 from urllib.parse import quote
-
-import markdown
 from fastapi import FastAPI, File, Form, HTTPException, Request, UploadFile
 from fastapi.responses import HTMLResponse, RedirectResponse
 from jinja2 import BaseLoader, Environment, TemplateNotFound
@@ -193,19 +193,56 @@ def bootstrap_secrets() -> str:
 
 
 # -----------------------------------------------------------------------------
-# Markdown → HTML
+# Markdown → HTML (marknb: https://cnb.cool/whcself/marknb)
 # -----------------------------------------------------------------------------
 
-_MD_EXTENSIONS = [
-    "markdown.extensions.fenced_code",
-    "markdown.extensions.tables",
-    "markdown.extensions.nl2br",
-    "markdown.extensions.sane_lists",
-]
+_MARKNB_DEFAULT = 65536
+
+
+def _load_marknb() -> ctypes.CDLL:
+    lib_path = os.environ.get("MARKNB_LIB")
+    if not lib_path:
+        here = Path(__file__).resolve().parent
+        for candidate in (
+            here / "vendor" / "marknb" / "libmarknb.so",
+            Path("/usr/local/lib/libmarknb.so"),
+        ):
+            if candidate.is_file():
+                lib_path = str(candidate)
+                break
+    if not lib_path:
+        print(
+            "找不到 marknb 动态库。请先运行: bash scripts/install.sh（升级: bash scripts/upgrade.sh）",
+            file=sys.stderr,
+        )
+        sys.exit(1)
+
+    lib = ctypes.CDLL(lib_path)
+    lib.marknb_parse.argtypes = [
+        ctypes.c_char_p,
+        ctypes.c_size_t,
+        ctypes.c_char_p,
+        ctypes.c_size_t,
+        ctypes.POINTER(ctypes.c_size_t),
+    ]
+    lib.marknb_parse.restype = ctypes.c_int
+    return lib
+
+
+_MARKNB = _load_marknb()
 
 
 def render_markdown(md_text: str) -> str:
-    return markdown.markdown(md_text, extensions=_MD_EXTENSIONS)
+    md = md_text.encode("utf-8")
+    cap = max(len(md) * 4 + 256, _MARKNB_DEFAULT)
+    limit = len(md) * 64 + 4096
+    while cap <= limit:
+        buf = ctypes.create_string_buffer(cap)
+        out_len = ctypes.c_size_t(0)
+        if _MARKNB.marknb_parse(md, len(md), buf, cap, ctypes.byref(out_len)) == 0:
+            return buf.raw[: out_len.value].decode("utf-8")
+        cap *= 2
+    raise RuntimeError("marknb: output buffer exhausted")
 
 
 # -----------------------------------------------------------------------------