The finished-game export (GCG + a new PNG of the final position) is one
signed, short-lived relative URL (game.export_url; HMAC-SHA256, 10-min
TTL, BACKEND_EXPORT_SIGN_KEY) resolved against the client's own origin
and delivered by the best affordance each platform has (five on-device
review rounds):
- TG Android/desktop: native showPopup chooser -> native downloadFile
dialog (bridge-only chain, activation-safe).
- TG iOS: app-modal chooser -> OS share sheet with the fetched file
(a popup callback cannot supply the activation the sheet needs).
- VK iOS: VKWebAppDownloadFile for both formats.
- VK Android: the PNG opens in VK's native image viewer, the GCG copies
to the clipboard (the VK Android downloader hangs on any download,
Content-Length/Range notwithstanding).
- VK desktop iframe / desktop browsers: plain anchor downloads.
- Mobile browsers: the OS share sheet (fetch-then-share).
- Legacy TG (< Bot API 8.0): app modal + GCG clipboard, no image option.
The PNG is rasterized on demand by the new internal `renderer` sidecar
(node:22-slim + skia-canvas + baked Liberation/Noto Color Emoji fonts)
executing the SAME ui/src/lib/gameimage.ts the ui project unit-tests;
the backend rebuilds the render payload from the journal +
engine.AlphabetTable, and the device date locale, IANA time zone and
localized non-play labels ride the signed URL. Nothing is stored — the
artifact re-derives from the immutable journal on each GET. The gateway
forwards /dl/* (caddy @gateway matcher extended) behind the per-IP
public rate limiter and serves bytes via http.ServeContent.
Deploy: renderer service in compose + prod overlay + rolling order +
prod push list; TEST_/PROD_EXPORT_SIGN_KEY secrets; the sidecar smoke
runs in the ui CI job. Docs: ARCHITECTURE, FUNCTIONAL(+_ru), UI_DESIGN,
TESTING, deploy/README, renderer/README.
Telegram's native showPopup delivers its callback with no user
activation, so navigator.share (TG iOS) and clipboard writes (TG
Android GCG copy) silently fail from it — the chooser is now always the
app's own modal, keeping the button click's gesture alive for the
delivery APIs.
The data:URL preview modal is dropped: the Android TG/VK long-press
menu mangles data: URLs (dead download, black-screen open, base64
clipboard garbage), so a binary PNG has no working client-side route in
those webviews at all. The image option is withheld there until the
server-rendered signed-URL delivery (Telegram downloadFile /
VKWebAppDownloadFile) lands; the plain web and mobile browsers keep it.
On-device findings by the owner on the test contour (TG iOS, TG
Android, VK Android).
The history header's export button now opens a chooser — Telegram's
native popup inside Telegram, the app's own modal elsewhere — offering
the GCG file and a new client-rendered PNG of the final position
(lib/gameimage, Canvas 2D, lazy dynamic import, zero dependencies):
light theme, classic A..O/1..15 axes, label-free premium fills, and a
fixed-typography per-seat scoresheet with GCG-style move coordinates,
multi-word sub-lines, endgame rack-settlement row, winner trophy and a
hostname + device-locale finish date footer; a long game stretches the
board, never the typography.
Delivery mirrors the GCG rules (Web Share with no blob fallback, else
download) except on Android Telegram/VK WebViews and the desktop VK
iframe, where a binary PNG has no clipboard-text fallback: those get a
preview modal with a long-press/right-click save hint and a copy-image
button where ClipboardItem exists.
developer
Ilia Denisov