Changelog

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All notable changes to this project are documented here. The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

0.2.2 - 2026-07-09

Robustness release: no user action, handler return value, or malformed Slack frame can take a transport down.

Fixed

  • A view_submission handler can no longer take down the transport. When a handler returned an {:ack, map} whose payload wasn't JSON-encodable (e.g. it held a tuple), encoding the ACK frame raised inside the transport process — on Socket Mode this crashed the connection and the supervisor's restart re-read the same envelope, producing a crash-reconnect loop. The payload is now checked for encodability in Slink.Dispatcher.ack_result/3; a non-encodable one is logged and degrades to %{} (closing the modal), like a handler crash already does.
  • A malformed Slack frame can no longer crash the Socket Mode connection. Slink.Event parsing and accessors used get_in/2, which raises when a value Slack normally nests as a map (a channel, view, item, or the envelope payload itself) arrives as a string, list, or null. Since event_id/1 and event construction run in the socket process, that raise dropped the connection. All parsing and accessors are now total — a wrong-shaped payload yields nil/empty defaults instead of raising — and the socket wraps per-message handling as a final backstop.
  • A bad reply body no longer crashes a channel's rate-limit worker. If a handler's reply carried a body the Web API client couldn't encode, the raise killed the per-channel Slink.Rate.Channel worker and dropped everything else queued for that channel. The send is now wrapped so a raising call is logged and draining continues, and Slink.Rate tolerates a worker that fails to start rather than crashing the caller.
  • The Events API plug no longer 500s on a form body with invalid percent-encoding — URI.decode_query/1 raising now degrades to an empty payload.

0.2.1 - 2026-07-09

Fixed

  • reply/3 to a reaction event no longer crashes. reaction_added / reaction_removed nest their target under payload["item"], so Event.channel/1, ts/1 now read it there — previously a reply to a reaction raised ArgumentError (no channel) and working/3 was a no-op.

Changed

  • Event.command/1 unwraps Slack link markup to plain text. A linkified address (<mailto:a@b.com|a@b.com>) now comes through as the bare a@b.com, and <@U1|alice> / <#C1|general> / <https://x|label> reduce to their name/url — so the addressed text reads as a human typed it. A bare <@U1> (e.g. the bot's own mention) still drops out.

0.2.0 - 2026-07-09

Added

  • Slash commands, end to end. Both transports now decode slash-command payloads (application/x-www-form-urlencoded over HTTP). reply/3 routes by event kind — a channel post for messages and interactions, or the response_url for a slash command (to: :ephemeral default, or :channel) — and raises clearly when an event has no channel to reply to (e.g. a view_submission). New Slink.Event accessors: command_name/1, response_url/1, trigger_id/1.
  • Interactivity & modals. Interactions are routed on their inner type (:block_actions, :view_submission, :shortcut, …). A view_submission handler may return {:ack, map} to control the modal (validation errors, update, push) — it runs synchronously so Slack gets the response in time. New helper open_modal/2 (imported by use Slink) and Slink.API.open_view/3, update_view/3, push_view/3, publish_view/3 (App Home). New Slink.Event accessors: actions/1, action_id/1, action_value/1, callback_id/1, view/1, view_values/1.
  • Event deduplication (Slink.Dedup). Slack's retried deliveries (same event_id) dispatch only once. On by default; config :slink, :dedup, false to disable, :dedup_ttl_ms to tune. New Slink.Event.event_id/1, retry?/1, retry_attempt/1.
  • Wider Web API surface (Slink.API): update_message/5, delete_message/3, post_ephemeral/5, get_permalink/3, user_info/2, and respond/2 (post to a response_url). call/3 now retries HTTP 429s, honouring Retry-After.

0.1.0 - 2026-07-08

Initial release.

Added

  • One event-handling contract, two transports. Write a bot once against the Slink behaviour and run it over either transport unchanged.
    • Slink.SocketMode — dials out to Slack over a WebSocket (Mint.WebSocket), no public endpoint required. Opens the connection via apps.connections.open, auto-reconnects, and optionally auto-joins channels on boot (:join).
    • Slink.EventsApi.Plug — a Plug for Slack's HTTP event callbacks. Mount it in a Plug/Phoenix router or run it standalone with Bandit.
  • Request hardening (Events API): HMAC-SHA256 signature verification against the raw body, constant-time comparison, timestamp-freshness (replay) window, request-body size cap, and automatic url_verification handshake.
  • Normalised events. Slink.Event collapses Socket Mode envelopes and HTTP payloads into one shape; both transports acknowledge to Slack before your handler runs and dispatch off-process, so a slow handler never blows Slack's ~3s ACK window.
  • Handler helpers (imported by use Slink): send_message/3,4, reply/2,3, working/2,3, and in_thread?/1.
  • Per-channel outbound rate limiting (Slink.Rate) to stay within Slack's ~1 message/sec/channel limit. Tunable via config :slink, :rate_interval_ms.
  • Web API client (Slink.API) built on Req.
  • Slink.enabled?/1 to conditionally start a bot from config.
  • A shippable app manifest (manifest.json) and a runnable Slink.ExampleBot.