fix: publish the directory page readable by the web server

mews/pages.py

@@ -210,6 +210,10 @@ def write_directory(target: str, rows: list[sqlite3.Row]) -> list[str]:
             )
         temporary = destination.with_name("." + destination.name + ".tmp")
         temporary.write_bytes(text)
+        # The web server reads this file straight off disk as another user, so
+        # it is made readable on purpose. The service runs with a private umask
+        # to keep the database to itself, and that would otherwise apply here.
+        temporary.chmod(0o644)
         os.replace(temporary, destination)
 
     warnings = [str(f) for f in result.warnings]

tests/test_service.py

@@ -344,6 +344,20 @@ def test_a_hostile_title_is_escaped_and_stripped(connection, tmp_path):
     assert validate_bytes(target.read_bytes()).conforms
 
 
+def test_the_directory_page_is_readable_by_the_web_server(connection, tmp_path):
+    """It is served off disk by another user, whatever umask the service has."""
+    import os
+    import stat
+
+    target = tmp_path / "directory.html"
+    old_umask = os.umask(0o077)
+    try:
+        pages.write_directory(str(target), db.listed(connection))
+    finally:
+        os.umask(old_umask)
+    assert stat.S_IMODE(target.stat().st_mode) == 0o644
+
+
 def test_an_empty_directory_still_conforms(connection, tmp_path):
     from mews.lint import validate_bytes