fix(commands): make /debug preview the caption a link would actually send

`/debug` reported `Fetched::caption`, the site's built-in caption, so a
chat's `/set_format` override never showed up in the preview — the command
looked like a no-op, and the `/set_format` success reply now tells users to
preview with `/debug`, which made that advice wrong.

`preview_caption` mirrors the send paths instead: the per-site format
override (`caption_from_fields`, empty → built-in) plus the long-post
quoting. Reported from a live run against the test bot.
This commit is contained in:
2026-09-20 17:30:55 +08:00
parent d4c36feb9a
commit 5b77d14497
2 changed files with 113 additions and 3 deletions
+1 -1
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@@ -20,7 +20,7 @@ Telegram update → Dispatcher (polling or axum webhook) → dptree branches
Message flow: `message_handler` extracts URLs (from `url`/`text_link` entities, text + caption, deduped) → `x_media::site::fetch(url)``Fetched` → builds a `Task``send::send_media_sequence` (media groups ≤ 10, caption on first item) or `send::send_animation`. On Telegram URL-fetch failure or size error (`send_batch_via_upload`): download via `x_media::site::download_media` to a temp file (≤ 10 MiB), sniff magic bytes (`sniff_ext`), upload via multipart; oversized items fall back to `fallback_url`. On failure: `enqueue_retry` persists resume-state `Task` into the SQLite queue → workers lease (120 s lock TTL) → retry with exponential backoff (≤ 30 s, `MAX_RETRIES = 2`) → dead-letter → `notify_failure`. Success → `post_send_actions`: edit-before-forward prompt with inline buttons, or `copy_messages` to the bound forward channel.
Debug command: `/debug <url>` runs the same `x_media::site::fetch` and replies with `debug_report` (`handlers/commands.rs`) — site id, normalized cache key, source URL, title/author/tags, sensitive flag, caption and the media list — nothing is sent, cached or forwarded; the report is capped at 4000 chars and sent with HTML parse mode: raw fields are escaped, and the caption is wrapped in a `<blockquote>` so it renders exactly like the sent media caption (escaped text and links included).
Debug command: `/debug <url>` runs the same `x_media::site::fetch` and replies with `debug_report` (`handlers/commands.rs`) — site id, normalized cache key, source URL, title/author/tags, sensitive flag, caption and the media list — nothing is sent, cached or forwarded; the report is capped at 4000 chars and sent with HTML parse mode: raw fields are escaped, and the caption is wrapped in a `<blockquote>` so it renders exactly like the sent media caption (escaped text and links included). The caption it shows is `preview_caption`'s: the chat's per-site format override plus the long-post quoting, i.e. exactly what the send paths produce — showing the raw built-in caption made `/set_format` look like a no-op, and the `/set_format` success reply points users at `/debug` to preview.
User-facing failure text is a function of the error class, never one generic sentence: `urls::fetch_error_message` maps `FetchError::NotFound` (post gone), `Sensitive` (withheld, needs `TWITTER_AUTH_TOKEN`), `Blocked` (source risk control), `Disabled { site }` (a registered site switched off — pixiv without a token, the one case `fetch` answers `Err` instead of `Ok(None)`) and `Transient`/`Http` (source down) apart. The same distinction drives the group hint: a supported link posted in a group (not a channel) gets one `GROUP_LINK_HINT` reply, because the link pipeline is private-chat only.