stickerfetch: exporting sticker, emoji and reaction seeds

cmd/stickerfetch downloads sticker sets, custom emoji, reactions and message effects from official Telegram and writes them in the layout SeedMedia imports at startup from TELESRV_STICKER_SEED_DIR (data/sticker-seed by default). It is a fetcher only: it never talks to telesrv.

Session and API credentials

It needs an authorized user session. The SESSION file path defaults to /tmp/appearance.session; the QR login of cmd/giftfetch produces a compatible session without a phone number (see giftfetch.md):

SESSION=$HOME/.tg-seed.session go run ./cmd/giftfetch -login-qr

The built-in TDesktop API id is shared by everyone and Telegram may answer it with API_ID_PUBLISHED_FLOOD. Set your own credentials from https://my.telegram.org to avoid that (giftfetch reads the same variables):

export TG_API_ID=123456 TG_API_HASH=0123456789abcdef0123456789abcdef

Running

SESSION=$HOME/.tg-seed.session go run ./cmd/stickerfetch [-timeout 12m] <out_dir> <spec> [spec...]

-timeout bounds the whole run (default 12 minutes). featured_emoji and featured_stickers download a hundred sets or more; give them hours, e.g. -timeout 3h. Re-running is cheap: files that already exist with the expected size are not downloaded again.

Spec	Source
`short:<name>`	a set by short name (regular, mask or custom emoji)
`id:<id>:<access_hash>`	a set by id
`emoji_default_statuses`, `emoji_channel_default_statuses`, `emoji_default_topic_icons`	default emoji status / topic icon sets
`premium_gifts`, `ton_gifts`	gift sticker sets
`animated_emoji`, `animated_emoji_animations`, `emoji_generic_animations`	big animated emoji and their interaction animations
`dice:<emoji>`	dice animations (`🎲 🎯 🏀 ⚽ 🎳 🎰`)
`effects`	`messages.getAvailableEffects`
`reactions`	`messages.getAvailableReactions`
`featured_emoji`	every set in `messages.getFeaturedEmojiStickers`
`featured_stickers`	every set in `messages.getFeaturedStickers`

A set spec writes <out_dir>/<ShortName>_<id>/set_info.json plus stickers/<doc_id>.<tgs|webm|webp>. reactions and effects write telegram_reactions_export/ and telegram_effects_export/ directly under <out_dir>.

Building a seed directory

SeedMedia looks for these subdirectories of the seed root:

Directory	Contents	Command
`telegram_default_stickers_export/`	system sets; the kind comes from `input_set_type` in `set_info.json`	`stickerfetch <root>/telegram_default_stickers_export animated_emoji emoji_default_statuses ...`
`telegram_emoji_export/`	custom emoji sets (not limited by `TELESRV_STICKER_SEED_MAX_SETS`)	`stickerfetch <root>/telegram_emoji_export featured_emoji`
`telegram_stickers_export/`	regular sticker sets	`stickerfetch <root>/telegram_stickers_export featured_stickers`
`telegram_reactions_export/`	reactions	`stickerfetch <root> reactions`
`telegram_effects_export/`	message effects	`stickerfetch <root> effects`

In Docker the seed directory is mounted read-only from TELESRV_STICKER_SEED_HOST_DIR (see deploy/docker/.env.example). Files must be readable by the server user; stickerfetch writes them with mode 0644.

Thumbs

Every document is exported with its thumbs: inline PhotoPathSize / PhotoStrippedSize / PhotoCachedSize bytes go into the JSON as hex, and downloadable PhotoSize renditions are stored next to the document as <doc_id>_thumb<N>_PhotoSize_type<t>.jpg (the content may be WebP; the server sniffs it). They are not optional: Android shows a .tgs sticker without thumbs as a file attachment, the emoji picker shows empty cells for custom emoji without them, and the server draws the still image of emoji avatars from them.

Importing

New and changed sets are picked up on the next server start. Reactions are imported only while the reaction table is empty or incomplete, so replacing an existing reaction export needs a cleared available_reactions table.