Split share.py into modules by responsibility

config.py  — share.config loading, constants, load_config(), client_cfg()
cert.py    — get_local_ip(), ensure_cert()
cleanup.py — cleanup_loop()
server.py  — ShareServer, Handler, file_type()
share.py   — main() entry point only

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

cert.py

@@ -0,0 +1,42 @@
+"""Self-signed certificate generation."""
+
+import socket
+import subprocess
+from pathlib import Path
+
+from config import CERT_DAYS, CERT_KEY_BITS
+
+
+def get_local_ip() -> str:
+    try:
+        with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as s:
+            s.connect(("8.8.8.8", 80))
+            return s.getsockname()[0]
+    except OSError:
+        return "127.0.0.1"
+
+
+def ensure_cert(cert_dir: Path, extra_ips: list[str] | None = None) -> tuple[Path, Path]:
+    """Generate self-signed cert if missing. Returns (certfile, keyfile)."""
+    cert_dir.mkdir(parents=True, exist_ok=True)
+    cert = cert_dir / "cert.pem"
+    key = cert_dir / "key.pem"
+    if cert.is_file() and key.is_file():
+        return cert, key
+    cert.unlink(missing_ok=True)
+    key.unlink(missing_ok=True)
+
+    ips = {"127.0.0.1", get_local_ip()}
+    if extra_ips:
+        ips.update(extra_ips)
+    san = ",".join([f"IP:{ip}" for ip in sorted(ips)] + ["DNS:localhost"])
+
+    subprocess.run([
+        "openssl", "req", "-x509", "-newkey", f"rsa:{CERT_KEY_BITS}",
+        "-keyout", str(key), "-out", str(cert),
+        "-days", str(CERT_DAYS), "-nodes",
+        "-subj", "/CN=Share",
+        "-addext", f"subjectAltName={san}",
+    ], check=True, capture_output=True)
+    print(f"  Generated self-signed cert in {cert_dir}")
+    return cert, key