Initialize Clash Web source and deployment documentation

scripts/fetch-rules.py

@@ -0,0 +1,34 @@
+#!/usr/bin/env python3
+"""Cache mainland domain/IP rule sets locally. Does not restart any service."""
+import argparse
+import os
+import tempfile
+import urllib.request
+from pathlib import Path
+
+parser = argparse.ArgumentParser()
+parser.add_argument('--output', default='data/mihomo/rules')
+args = parser.parse_args()
+directory = Path(args.output)
+directory.mkdir(parents=True, exist_ok=True)
+files = {'cn-domain.mrs': 'geosite/cn.mrs', 'cn-ip.mrs': 'geoip/cn.mrs'}
+downloads = {}
+for name, remote in files.items():
+    request = urllib.request.Request('https://raw.githubusercontent.com/MetaCubeX/meta-rules-dat/meta/geo/' + remote, headers={'User-Agent': 'ClashWeb-build'})
+    with urllib.request.urlopen(request, timeout=60) as response:
+        data = response.read(32 * 1024 * 1024 + 1)
+    # MRS resources use a Zstandard frame; core validation checks the decoded payload.
+    if len(data) > 32 * 1024 * 1024 or data[:4] != b'\x28\xb5\x2f\xfd':
+        raise SystemExit(f'{name}: invalid MRS resource or size exceeds limit')
+    downloads[name] = data
+for name, data in downloads.items():
+    fd, temporary = tempfile.mkstemp(dir=directory, prefix='.rules-')
+    try:
+        with os.fdopen(fd, 'wb') as stream:
+            stream.write(data)
+        os.chmod(temporary, 0o640)
+        os.replace(temporary, directory / name)
+    finally:
+        if os.path.exists(temporary):
+            os.unlink(temporary)
+    print(f'Cached {name}: {len(data)} bytes')