WIP

server.py

@@ -0,0 +1,95 @@
+#!/usr/bin/env python3
+"""Static file server for the rendered Bible site.
+
+Stdlib only, so the container needs nothing but a Python base image. Its one
+job beyond serving files is getting cache headers right: the service worker
+owns the offline copy, and if the worker or the pages that register it are
+served stale, a new build can never reach a device that already installed the
+old one.
+
+Expects to sit behind something that terminates TLS. That is not optional for
+the offline app: browsers only register a service worker in a secure context,
+so a device loading this over plain http:// from a LAN address installs the
+page but never gets an offline copy.
+"""
+
+from __future__ import annotations
+
+import argparse
+import os
+import signal
+import sys
+from functools import partial
+from http.server import SimpleHTTPRequestHandler, ThreadingHTTPServer
+
+# Revalidate every time: these are what carry an update to an installed app.
+NO_CACHE_NAMES = {"sw.js"}
+NO_CACHE_EXTS = {".html", ".webmanifest"}
+
+
+class Handler(SimpleHTTPRequestHandler):
+    extensions_map = {
+        **SimpleHTTPRequestHandler.extensions_map,
+        ".html": "text/html; charset=utf-8",
+        ".css": "text/css; charset=utf-8",
+        ".js": "text/javascript; charset=utf-8",
+        ".json": "application/json; charset=utf-8",
+        ".webmanifest": "application/manifest+json; charset=utf-8",
+        ".png": "image/png",
+        ".svg": "image/svg+xml",
+    }
+    server_version = "bible-static"
+    sys_version = ""
+
+    def end_headers(self):
+        path = self.path.split("?", 1)[0]
+        name = os.path.basename(path)
+        ext = os.path.splitext(name)[1].lower()
+        if name in NO_CACHE_NAMES or ext in NO_CACHE_EXTS or path.endswith("/"):
+            self.send_header("Cache-Control", "no-cache")
+        else:
+            self.send_header("Cache-Control", "public, max-age=604800")
+        # Lets the worker claim the whole origin even if it moves off root.
+        self.send_header("Service-Worker-Allowed", "/")
+        self.send_header("X-Content-Type-Options", "nosniff")
+        super().end_headers()
+
+    def log_message(self, fmt, *args):
+        sys.stdout.write("%s %s\n" % (self.address_string(), fmt % args))
+        sys.stdout.flush()
+
+
+def main(argv=None):
+    ap = argparse.ArgumentParser(description=__doc__,
+                                 formatter_class=argparse.RawDescriptionHelpFormatter)
+    ap.add_argument("--root", default=os.environ.get("SITE_ROOT", "books"),
+                    help="directory to serve (default: books)")
+    ap.add_argument("--host", default=os.environ.get("HOST", "0.0.0.0"))
+    ap.add_argument("--port", type=int, default=int(os.environ.get("PORT", "8080")))
+    args = ap.parse_args(argv)
+
+    root = os.path.abspath(args.root)
+    if not os.path.isdir(root):
+        sys.exit("site root not found: %s" % root)
+
+    httpd = ThreadingHTTPServer((args.host, args.port),
+                                partial(Handler, directory=root))
+    httpd.daemon_threads = True
+
+    def stop(_signum, _frame):
+        httpd.shutdown()
+
+    signal.signal(signal.SIGTERM, stop)
+    signal.signal(signal.SIGINT, stop)
+
+    print("serving %s at http://%s:%d" % (root, args.host, args.port))
+    sys.stdout.flush()
+    try:
+        httpd.serve_forever()
+    finally:
+        httpd.server_close()
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())