Fix

server.py

@@ -220,12 +220,19 @@ class Handler(SimpleHTTPRequestHandler):
         path = self.path.split("?", 1)[0]
         name = posixpath.basename(path)
         ext = posixpath.splitext(name)[1].lower()
-        if name in NO_CACHE_NAMES or ext in NO_CACHE_EXTS or path.endswith("/"):
+        # A dot in the last segment means a file; anything else is a page. The
+        # same test the worker's isFile() makes, and it has to stay the same
+        # one. Matching on the extension alone was right while pages were
+        # /GEN.html; the moment the URL space went extensionless it silently
+        # handed every book a week of browser caching that no rebuild could
+        # get past -- the worker's own fetch reads the browser cache too, so
+        # even a fresh library cache was being filled from a stale one.
+        if name in NO_CACHE_NAMES or ext in NO_CACHE_EXTS or "." not in name:
             self.send_header("Cache-Control", "no-cache")
         else:
             self.send_header("Cache-Control", "public, max-age=604800")
-        # One URL, two bodies: a navigation to /GEN.html gets the boot page and
-        # a fetch of it gets the fragment. Without this the browser cache keeps
+        # One URL, two bodies: a navigation to /GEN gets the boot page and a
+        # fetch of it gets the fragment. Without this the browser cache keeps
         # one entry for both, and boot.html asking for its own fragment is
         # handed back a copy of itself -- a document nested inside a document.
         self.send_header("Vary", "Sec-Fetch-Mode")