The apps subsystem previously sent Cache-Control: public, max-age=300|3600,
must-revalidate but no ETag. With must-revalidate and no validator, the
browser cannot return 304 — it has to refetch the full body once max-age
expires. For mdedit that's 920 KB on every reload after an hour.
Add a content-addressed ETag (sha256 hex prefix, 32 chars) to:
- apps/handler.go's serveBody + serveEmbedded (both paths now emit ETag
+ handle If-None-Match short-circuit to 304)
- handler/directory.go's embedded:browse fallback (mirror behavior so
the bare-directory landing serves the same way)
Drop max-age to 0 with must-revalidate: every page load revalidates,
but a matching ETag returns 304 with empty body. Steady-state cost of
a reload drops from N KB to a few hundred bytes. When the binary is
redeployed, the ETag changes (content hash) and the next request
returns 200 with the new bytes.
Tests in apps/handler_test.go cover both paths:
- TestServer_Embedded_ConditionalGET: full GET, matching INM, stale INM
- TestEmbeddedETag_Stable: same bytes → same ETag, different → different
Live smoke (curl against zddc-server -root /tmp/empty):
GET / → 200, ETag set, body = 80919 bytes (landing.html)
GET / + INM:tag → 304 Not Modified, empty body
Adds internal/apps/ package serving the five tool HTMLs at virtual paths
based on the surrounding folder name convention:
archive every directory (multi-project, project, archive, vendor)
classifier any Incoming/Working/Staging directory and subtree
mdedit any Working directory and subtree
transmittal any Staging directory and subtree
landing only at deployment root
The current-stable build of every tool is //go:embed'd into the binary
at compile time — that's the default with zero config. Operators
override per-directory via .zddc apps: entries; closer-to-leaf wins.
Spec syntax (in any apps: value):
stable / beta / alpha / :stable channel
v0.0.4 / v0.0 / v0 / :v0.0.4 version
https://my-mirror/releases URL prefix only
https://my-mirror/releases:beta URL prefix + channel
https://my-fork/archive.html terminal full URL
./local.html / /abs/path.html terminal local path
The special apps.default key provides a baseline URL prefix and channel
inherited by any app not overridden per-name. Per-axis cascade: a deeper
.zddc can override the URL, the channel, or both.
Cascade walks root→leaf; default applies first at each level, then the
per-app entry. Terminal sources (paths and full .html URLs) short-circuit
composition; deeper non-terminal entries override parent terminals.
URL sources fetch once on first request and cache forever in
<ZDDC_ROOT>/_app/<host>/<path> — different upstreams with the same
filename stay distinct. No background refresh, no SHA-256 verification:
operators delete the cache file to force a refetch. Concurrent misses
for the same source dedupe via a 30-line hand-rolled singleflight.
Per-request override: any user can append ?v=<spec> to a tool URL
(e.g. ?v=beta, ?v=v0.0.4, ?v=:alpha, ?v=https://mirror/releases:beta)
to ask for a different build for one request. Security: ?v= serves
ONLY versions already in the cache (cache miss returns 404; path
sources are rejected outright with 400). Users cannot trigger
arbitrary upstream fetches via crafted URLs.
Failed URL fetches (network down, 5xx) fall back to embedded with a
one-time WARN log. The X-ZDDC-Source response header reports what
served: fetch:URL / cache:URL / path:/abs / embedded:<app>@<build>.
Wire-in (cmd/zddc-server/main.go): dispatch routes <dir>/<app>.html
through apps.MatchAppHTML + AppAvailableAt + apps.Server.Serve when
no real file exists. Direct URL access to /_app/... is blocked at
the dispatch layer — cached files must go through the apps resolver
so they get correct Content-Type and ACL gating.
Schema (internal/zddc/file.go): ZddcFile gains Apps map[string]string
for cascade overrides. Validator (internal/zddc/validate.go) accepts
the special "default" key alongside the five canonical app names and
all spec forms.
Removes ZDDC_APPS_* env vars (no admin UI, no refresh interval, no
upstream allow-list — the simpler model has fewer knobs).
40+ unit tests across the new package: parser shapes, cascade
resolution with default+per-app interactions, terminal short-circuit
semantics, ?v= cache-only enforcement, embedded fallback, atomic
cache writes, singleflight dedup. Plus end-to-end dispatch tests in
cmd/zddc-server/main_test.go.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
