Conditional requests for static files (ETag / Last-Modified / 304)#298
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balat wants to merge 4 commits into
Open
Conditional requests for static files (ETag / Last-Modified / 304)#298balat wants to merge 4 commits into
balat wants to merge 4 commits into
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Response.respond_file now always adds a weak ETag (derived from the file's modification time and size) and a Last-Modified header, and takes optional If-None-Match / If-Modified-Since values; when they match, it answers 304 Not Modified with an empty body, keeping the validators (RFC 7232).
Pass the request's If-None-Match and If-Modified-Since headers to Response.respond_file so that unchanged static files return 304 Not Modified.
Checks that static files carry ETag and Last-Modified, that re-requesting with either validator returns 304 with an empty body, and that a non-matching ETag still serves the file.
This was referenced Jun 26, 2026
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What
Static files are now served with validators and honour conditional requests, so
browsers and caches can revalidate cheaply (RFC 7232) — even
python -m http.serverdid this and we did not.
modification time and size) and a Last-Modified header.
that matches gets 304 Not Modified with an empty body, keeping the
validators.
Where
Response.respond_filegained the ETag/Last-Modified generation and optional?if_none_match/?if_modified_sinceparameters; Staticmod passes therequest's headers. If-None-Match takes precedence over If-Modified-Since per
RFC 7232; the latter only returns 304 on an exact match of our Last-Modified
value, so it never answers 304 wrongly.
Tests
test/conditional-requests.tchecks the validators are present, thatre-requesting with either validator returns 304 with an empty body, and that a
non-matching ETag still serves the file.
Note
Independent of #297 (reverse proxy); both branch from master.