rigor-actioncable

Validates ActionCable broadcast call sites against a statically discovered channel index: <X>Channel.broadcast_to(record, data) checks that the channel class exists, and ActionCable.server.broadcast("stream_name", data) checks that the literal stream name was registered with stream_from in some channel. It reads source only — no actioncable runtime dependency.

It ships bundled in rigortype. Activate it under plugins::

plugins:
  - rigor-actioncable

What it checks

app/channels/chat_channel.rb

class ChatChannel < ApplicationCable::Channel
  def subscribed
    stream_from "chat_room_5"
  end
end

ChatChannel.broadcast_to(room, message: "hi")               # info:  channel exists
ActionCable.server.broadcast("chat_room_5", body: "hi")     # info:  registered stream
ChartChannel.broadcast_to(room, message: "hi")              # error: no channel (did you mean ChatChannel?)
ActionCable.server.broadcast("chat_room_42", body: "hi")    # warning: no such stream registration

Rule	Severity	Fires when
plugin.actioncable.broadcast-target	info	<X>Channel.broadcast_to(...) matched a discovered channel
plugin.actioncable.broadcast-stream	info	ActionCable.server.broadcast("...", ...) matched a registered stream_from literal
plugin.actioncable.unknown-channel	error	the receiver ends in Channel but is not in the index (with a did-you-mean)
plugin.actioncable.unknown-stream	warning	the literal stream name matched no stream_from registration (with a did-you-mean)
plugin.actioncable.load-error	warning	channel discovery failed (parse/read error) — once per file

The unknown-stream check is suppressed when any discovered channel registers a dynamic stream (stream_from interpolated_string or stream_for record) — the absence of a literal match doesn’t prove the stream is invalid. Non-Channel receivers and non-literal stream arguments pass through silently.

Configuration

plugins:
  - gem: rigor-actioncable
    config:
      channel_search_paths: ["app/channels"]                                            # default
      channel_base_classes: ["ApplicationCable::Channel", "ActionCable::Channel::Base"] # default

Limitations

• Direct-superclass match only. An indirect chain (AdminChannel < BaseChannel < ApplicationCable::Channel) needs BaseChannel listed in channel_base_classes.
• Action methods are indexed, not validated. Channel actions are invoked client-side via subscription.perform("action", data); Rigor does not analyse JavaScript, so the action index is informational.
• broadcast_to arity is not checked — it accepts any record + any data hash.
• Indirect stream_from (registered inside a helper method rather than directly in the channel body) is out of scope.
• Bare broadcast(...) without an explicit ActionCable.server receiver is skipped to avoid false positives on unrelated methods.

Plugin internals

The channel discoverer / index and the contract surfaces this plugin exercises are in the plugin’s README. To write a plugin, see examples/ and the rigor-plugin-author skill.