feat: add backend beamer live updates

README.md

@@ -30,6 +30,7 @@ bundle exec rspec
 Leader/follower tournament sync docs:
 
 - [doc/leader_follower.md](doc/leader_follower.md)
+- [doc/beamer_live_updates.md](doc/beamer_live_updates.md)
 
 ## Docker
 [Registry](https://gitlab.com/turniere/turniere-backend/container_registry)

app/channels/tournament_beamers_channel.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+class TournamentBeamersChannel < ApplicationCable::Channel
+  class << self
+    def stream_name(tournament_id:, beamer_name:)
+      "tournament_#{tournament_id}:beamers:#{beamer_name}"
+    end
+  end
+
+  def subscribed
+    tournament = Tournament.find(params[:tournament_id])
+    beamer_name = params[:beamer_name].presence
+    beamer = tournament.beamers.find_by(name: beamer_name) || tournament.beamers.find_by(name: Beamer::DEFAULT_NAME)
+
+    return reject unless beamer
+
+    stream_from self.class.stream_name(tournament_id: tournament.id, beamer_name: beamer.name)
+    transmit BeamerBroadcastPayload.build(beamer:, event: 'snapshot')
+  end
+end

app/models/beamer.rb

@@ -13,4 +13,37 @@ class Beamer < ApplicationRecord
   validates :display_state, presence: true, inclusion: { in: DISPLAY_STATES }
 
   delegate :owner, to: :tournament
+
+  before_update :store_previous_name_for_broadcast, if: :will_save_change_to_name?
+  before_destroy :store_snapshot_for_broadcast
+  after_commit :broadcast_state_change, on: %i[create update destroy]
+
+  private
+
+  def store_previous_name_for_broadcast
+    @broadcast_previous_name = name_in_database
+  end
+
+  def store_snapshot_for_broadcast
+    @broadcast_snapshot = BeamerBroadcastPayload.snapshot(self)
+  end
+
+  def broadcast_state_change
+    snapshot = @broadcast_snapshot || BeamerBroadcastPayload.snapshot(self)
+
+    BeamerBroadcast.call(
+      tournament_id: snapshot.fetch(:tournament_id),
+      beamer_names: [@broadcast_previous_name, snapshot.fetch(:name)].compact.uniq,
+      payload: BeamerBroadcastPayload.build(snapshot: snapshot, event: broadcast_event)
+    )
+  ensure
+    @broadcast_previous_name = nil
+    @broadcast_snapshot = nil
+  end
+
+  def broadcast_event
+    return 'deleted' if destroyed?
+
+    previous_changes.key?('id') ? 'created' : 'updated'
+  end
 end

app/serializers/beamer_serializer.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 class BeamerSerializer < ApplicationSerializer
-  attributes :name, :display_state, :qr_code_url, :logo_url
+  attributes :id, :name, :display_state, :qr_code_url, :logo_url
 end

app/services/beamer_broadcast.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+class BeamerBroadcast
+  class << self
+    def call(tournament_id:, beamer_names:, payload:)
+      Array(beamer_names).compact.uniq.each do |beamer_name|
+        ActionCable.server.broadcast(
+          TournamentBeamersChannel.stream_name(tournament_id:, beamer_name:),
+          payload
+        )
+      end
+    end
+  end
+end

app/services/beamer_broadcast_payload.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+class BeamerBroadcastPayload
+  class << self
+    def build(beamer: nil, snapshot: nil, event:)
+      data = snapshot || self.snapshot(beamer)
+
+      {
+        type: "beamer.#{event}",
+        event: event,
+        tournament_id: data.fetch(:tournament_id),
+        beamer: serialized_beamer(data)
+      }
+    end
+
+    def snapshot(beamer)
+      {
+        id: beamer.id,
+        tournament_id: beamer.tournament_id,
+        name: beamer.name,
+        display_state: beamer.display_state,
+        qr_code_url: beamer.qr_code_url,
+        logo_url: beamer.logo_url
+      }
+    end
+
+    private
+
+    def serialized_beamer(snapshot)
+      {
+        id: snapshot.fetch(:id),
+        name: snapshot.fetch(:name),
+        display_state: snapshot.fetch(:display_state),
+        qr_code_url: snapshot[:qr_code_url],
+        logo_url: snapshot[:logo_url]
+      }
+    end
+  end
+end

doc/beamer_live_updates.md

@@ -0,0 +1,64 @@
+# Beamer Live Updates
+
+Beamer/projector live updates are backend-owned and use Rails ActionCable at `/cable`.
+
+## Goal
+
+Frontend fullscreen pages talk only to `turniere-backend`.
+No `TURNIERE_MATCH_URL`.
+No Socket.IO dependency on `turniere-match`.
+
+## Transport
+
+- websocket endpoint: `GET /cable`
+- ActionCable channel: `TournamentBeamersChannel`
+- subscription params:
+  - `tournament_id`
+  - `beamer_name`
+
+If requested beamer does not exist, channel falls back to tournament default beamer when present.
+
+## Payload contract
+
+Initial subscribe snapshot:
+
+```json
+{
+  "type": "beamer.snapshot",
+  "event": "snapshot",
+  "tournament_id": 12,
+  "beamer": {
+    "id": 34,
+    "name": "default",
+    "display_state": "matches_all",
+    "qr_code_url": null,
+    "logo_url": null
+  }
+}
+```
+
+Mutation events use same `beamer` shape with `type` / `event` values:
+
+- `beamer.created`
+- `beamer.updated`
+- `beamer.deleted`
+
+## Broadcast source
+
+Broadcasts come from `Beamer` model commit callbacks.
+That means normal HTTP writes and follower-sync imports use same broadcast path.
+
+Covered mutations:
+
+- create
+- update
+- delete
+
+## Frontend expectation
+
+Frontend should:
+
+- fetch beamer config from backend REST API
+- subscribe to `TournamentBeamersChannel`
+- update fullscreen state from explicit `beamer` payload
+- reconnect if beamer name changes or current beamer gets deleted

e2e/lib/action_cable_client.rb

@@ -17,25 +17,26 @@ module TurniereE2E
     end
 
     def subscribe_team_action_lists!(tournament_id:)
-      connect!
       identifier = {
         channel: 'TournamentTeamActionListsChannel',
         tournament_id: tournament_id
       }.to_json
 
-      driver.text(
-        JSON.dump(
-          command: 'subscribe',
-          identifier: identifier
-        )
-      )
-
-      handshake_message = wait_for! do |message|
-        message['type'] == 'confirm_subscription' ||
-          (message['identifier'] == identifier && message['message'].is_a?(Hash))
+      subscribe!(identifier:) do |message|
+        team_action_lists_payload_message?(message)
       end
+    end
 
-      @messages << handshake_message if team_action_lists_payload_message?(handshake_message)
+    def subscribe_beamer!(tournament_id:, beamer_name:)
+      identifier = {
+        channel: 'TournamentBeamersChannel',
+        tournament_id: tournament_id,
+        beamer_name: beamer_name
+      }.to_json
+
+      subscribe!(identifier:) do |message|
+        beamer_payload_message?(message)
+      end
     end
 
     def wait_for_payload!(timeout: 20)
@@ -45,6 +46,12 @@ module TurniereE2E
       end.fetch('message')
     end
 
+    def wait_for_beamer_payload!(timeout: 20)
+      wait_for!(timeout: timeout) do |message|
+        beamer_payload_message?(message)
+      end.fetch('message')
+    end
+
     def close
       return if @closed
 
@@ -67,6 +74,24 @@ module TurniereE2E
 
     attr_reader :base_url, :socket, :driver
 
+    def subscribe!(identifier:)
+      connect!
+
+      driver.text(
+        JSON.dump(
+          command: 'subscribe',
+          identifier: identifier
+        )
+      )
+
+      handshake_message = wait_for! do |message|
+        message['type'] == 'confirm_subscription' ||
+          (message['identifier'] == identifier && yield(message))
+      end
+
+      @messages << handshake_message if yield(handshake_message)
+    end
+
     def connect!
       return unless @driver.nil?
 
@@ -143,5 +168,10 @@ module TurniereE2E
       payload = message['message']
       payload.is_a?(Hash) && payload['type'] == 'team_action_lists.updated'
     end
+
+    def beamer_payload_message?(message)
+      payload = message['message']
+      payload.is_a?(Hash) && payload['type'].to_s.start_with?('beamer.')
+    end
   end
 end

spec/e2e/http/tournament_beamers_websocket_spec.rb

@@ -0,0 +1,98 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require 'securerandom'
+require_relative '../../../e2e/lib/api_client'
+require_relative '../../../e2e/lib/action_cable_client'
+
+RSpec.describe 'Tournament beamer websocket HTTP E2E' do
+  required_env_vars = %w[
+    TURNIERE_E2E_BASE_URL
+    TURNIERE_E2E_EMAIL
+    TURNIERE_E2E_PASSWORD
+  ].freeze
+
+  before do
+    missing_vars = required_env_vars.reject { |name| ENV.key?(name) }
+    skip("HTTP E2E requires #{missing_vars.join(', ')}") unless missing_vars.empty?
+  end
+
+  let(:base_url) { ENV.fetch('TURNIERE_E2E_BASE_URL') }
+  let(:owner_email) { ENV.fetch('TURNIERE_E2E_EMAIL') }
+  let(:owner_password) { ENV.fetch('TURNIERE_E2E_PASSWORD') }
+  let(:client) { login_client }
+
+  it 'broadcasts beamer snapshots and updates over websocket' do
+    tournament = create_tournament(name_prefix: 'Ws Beamer')
+    create_beamer = client.post("/tournaments/#{tournament.fetch(:id)}/beamers", body: {
+                                  name: 'projector-a',
+                                  display_state: 'matches_all'
+                                })
+    expect(create_beamer[:status]).to eq(201)
+    beamer = create_beamer.fetch(:json)
+
+    cable_client = TurniereE2E::ActionCableClient.new(base_url:)
+    cable_client.subscribe_beamer!(tournament_id: tournament.fetch(:id), beamer_name: beamer.fetch(:name))
+
+    initial_payload = cable_client.wait_for_beamer_payload!
+    expect(initial_payload.fetch('type')).to eq('beamer.snapshot')
+    expect(initial_payload.dig('beamer', 'id')).to eq(beamer.fetch(:id))
+    expect(initial_payload.dig('beamer', 'display_state')).to eq('matches_all')
+
+    update = client.patch("/tournaments/#{tournament.fetch(:id)}/beamers/#{beamer.fetch(:id)}", body: {
+                            display_state: 'during_game',
+                            qr_code_url: 'https://example.com/qr',
+                            logo_url: '/static/logo.png'
+                          })
+    expect(update[:status]).to eq(200)
+
+    updated_payload = wait_for_beamer_payload!(
+      cable_client,
+      event_type: 'beamer.updated',
+      display_state: 'during_game'
+    )
+    expect(updated_payload.dig('beamer', 'qr_code_url')).to eq('https://example.com/qr')
+    expect(updated_payload.dig('beamer', 'logo_url')).to eq('/static/logo.png')
+
+    delete = client.delete("/tournaments/#{tournament.fetch(:id)}/beamers/#{beamer.fetch(:id)}")
+    expect(delete[:status]).to eq(204)
+
+    deleted_payload = wait_for_beamer_payload!(
+      cable_client,
+      event_type: 'beamer.deleted',
+      display_state: 'during_game'
+    )
+    expect(deleted_payload.dig('beamer', 'name')).to eq('projector-a')
+  ensure
+    cable_client&.close
+  end
+
+  def login_client
+    api_client = TurniereE2E::ApiClient.new(base_url:)
+    response = api_client.login!(email: owner_email, password: owner_password)
+
+    expect(response[:status]).to eq(200)
+    api_client
+  end
+
+  def create_tournament(name_prefix:)
+    response = client.post('/tournaments', body: {
+                             name: "#{name_prefix} #{SecureRandom.hex(3)}",
+                             description: 'Websocket beamer tournament',
+                             public: true
+                           })
+    expect(response[:status]).to eq(201)
+    response.fetch(:json)
+  end
+
+  def wait_for_beamer_payload!(cable_client, event_type:, display_state:, timeout: 20)
+    deadline = Time.now + timeout
+    loop do
+      payload = cable_client.wait_for_beamer_payload!(timeout: [deadline - Time.now, 0.1].max)
+      return payload if payload.fetch('type') == event_type &&
+                        payload.dig('beamer', 'display_state') == display_state
+
+      raise "beamer websocket payload not received within #{timeout}s" if Time.now >= deadline
+    end
+  end
+end

spec/e2e/http/tournament_follow_sync_beamers_websocket_spec.rb

@@ -0,0 +1,126 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require 'securerandom'
+require_relative '../../../e2e/lib/api_client'
+require_relative '../../../e2e/lib/action_cable_client'
+
+RSpec.describe 'Tournament follower sync beamer websocket HTTP E2E' do
+  required_env_vars = %w[
+    TURNIERE_E2E_EMAIL
+    TURNIERE_E2E_PASSWORD
+    TURNIERE_SOURCE_E2E_BASE_URL
+    TURNIERE_FOLLOWER_E2E_BASE_URL
+  ].freeze
+
+  before do
+    missing_vars = required_env_vars.reject { |name| ENV.key?(name) }
+    skip("HTTP E2E requires #{missing_vars.join(', ')}") unless missing_vars.empty?
+  end
+
+  let(:source_base_url) { ENV.fetch('TURNIERE_SOURCE_E2E_BASE_URL') }
+  let(:follower_base_url) { ENV.fetch('TURNIERE_FOLLOWER_E2E_BASE_URL') }
+  let(:owner_email) { ENV.fetch('TURNIERE_E2E_EMAIL') }
+  let(:owner_password) { ENV.fetch('TURNIERE_E2E_PASSWORD') }
+  let(:sync_token) { "sync-#{SecureRandom.hex(8)}" }
+  let(:source_client) { login_client(base_url: source_base_url) }
+
+  it 'broadcasts follower beamer websocket updates after source sync import' do
+    source = create_tournament(client: source_client, base_url: source_base_url, name_prefix: 'Ws Beamer Source')
+    follower = create_follower_tournament(name_prefix: 'Ws Beamer Follower')
+
+    configure_sync = source_client.patch("/tournaments/#{source.fetch(:id)}", body: {
+                                           sync_target_url: "#{follower_base_url}/tournaments/#{follower.fetch(:id)}/sync_state",
+                                           sync_auth_token: sync_token
+                                         })
+    expect(configure_sync[:status]).to eq(200)
+
+    follower_default_beamer = wait_for_default_beamer!(tournament_id: follower.fetch(:id))
+
+    cable_client = TurniereE2E::ActionCableClient.new(base_url: follower_base_url)
+    cable_client.subscribe_beamer!(tournament_id: follower.fetch(:id), beamer_name: follower_default_beamer.fetch(:name))
+    cable_client.wait_for_beamer_payload!
+
+    source_default_beamer = fetch_beamer(base_url: source_base_url, tournament_id: source.fetch(:id), beamer_name: Beamer::DEFAULT_NAME)
+    update = source_client.patch("/tournaments/#{source.fetch(:id)}/beamers/#{source_default_beamer.fetch(:id)}", body: {
+                                   display_state: 'groups'
+                                 })
+    expect(update[:status]).to eq(200)
+
+    follower_payload = wait_for_beamer_payload!(
+      cable_client,
+      event_type: 'beamer.updated',
+      display_state: 'groups'
+    )
+    expect(follower_payload.dig('beamer', 'name')).to eq(Beamer::DEFAULT_NAME)
+  ensure
+    cable_client&.close
+  end
+
+  def login_client(base_url:)
+    client = TurniereE2E::ApiClient.new(base_url:)
+    response = client.login!(email: owner_email, password: owner_password)
+    expect(response[:status]).to eq(200)
+    client
+  end
+
+  def create_tournament(client:, base_url:, name_prefix:)
+    response = client.post('/tournaments', body: {
+                             name: "#{name_prefix} #{SecureRandom.hex(3)}",
+                             description: 'Follower beamer websocket source tournament',
+                             public: true
+                           })
+    expect(response[:status]).to eq(201)
+    fetch_tournament(base_url:, tournament_id: response.dig(:json, :id))
+  end
+
+  def create_follower_tournament(name_prefix:)
+    client = login_client(base_url: follower_base_url)
+    response = client.post('/tournaments', body: {
+                             name: "#{name_prefix} #{SecureRandom.hex(3)}",
+                             description: 'Follower beamer websocket target tournament',
+                             public: true,
+                             read_only_mode: true,
+                             sync_auth_token: sync_token
+                           })
+    expect(response[:status]).to eq(201)
+    fetch_tournament(base_url: follower_base_url, tournament_id: response.dig(:json, :id))
+  end
+
+  def fetch_tournament(base_url:, tournament_id:)
+    client = TurniereE2E::ApiClient.new(base_url:)
+    response = client.get("/tournaments/#{tournament_id}")
+    expect(response[:status]).to eq(200)
+    response.fetch(:json)
+  end
+
+  def fetch_beamer(base_url:, tournament_id:, beamer_name:)
+    client = TurniereE2E::ApiClient.new(base_url:)
+    response = client.get("/tournaments/#{tournament_id}/beamers/by_name", params: { name: beamer_name })
+    expect(response[:status]).to eq(200)
+    response.fetch(:json)
+  end
+
+  def wait_for_default_beamer!(tournament_id:, timeout: 20)
+    deadline = Time.now + timeout
+    loop do
+      beamer = fetch_beamer(base_url: follower_base_url, tournament_id:, beamer_name: Beamer::DEFAULT_NAME)
+      return beamer if beamer.fetch(:name) == Beamer::DEFAULT_NAME
+
+      raise "follower default beamer not present within #{timeout}s" if Time.now >= deadline
+
+      sleep 0.5
+    end
+  end
+
+  def wait_for_beamer_payload!(cable_client, event_type:, display_state:, timeout: 20)
+    deadline = Time.now + timeout
+    loop do
+      payload = cable_client.wait_for_beamer_payload!(timeout: [deadline - Time.now, 0.1].max)
+      return payload if payload.fetch('type') == event_type &&
+                        payload.dig('beamer', 'display_state') == display_state
+
+      raise "follower beamer websocket payload not received within #{timeout}s" if Time.now >= deadline
+    end
+  end
+end

spec/models/beamer_spec.rb

@@ -42,4 +42,54 @@ RSpec.describe Beamer, type: :model do
       expect(beamer.owner).to eq(beamer.tournament.owner)
     end
   end
+
+  describe 'live broadcasts' do
+    it 'broadcasts create payload to current beamer stream' do
+      tournament = create(:tournament)
+      payload = nil
+
+      expect(BeamerBroadcast).to receive(:call) do |args|
+        payload = args.fetch(:payload)
+        expect(args.fetch(:tournament_id)).to eq(tournament.id)
+        expect(args.fetch(:beamer_names)).to eq(['projector'])
+      end
+
+      tournament.beamers.create!(name: 'projector', display_state: 'groups')
+
+      expect(payload[:type]).to eq('beamer.created')
+      expect(payload.dig(:beamer, :display_state)).to eq('groups')
+    end
+
+    it 'broadcasts update payload to previous and current beamer names when renamed' do
+      beamer = create(:beamer, name: 'old-name')
+      payload = nil
+
+      expect(BeamerBroadcast).to receive(:call) do |args|
+        payload = args.fetch(:payload)
+        expect(args.fetch(:beamer_names)).to contain_exactly('old-name', 'new-name')
+      end
+
+      beamer.update!(name: 'new-name', display_state: 'during_game')
+
+      expect(payload[:type]).to eq('beamer.updated')
+      expect(payload.dig(:beamer, :name)).to eq('new-name')
+      expect(payload.dig(:beamer, :display_state)).to eq('during_game')
+    end
+
+    it 'broadcasts delete payload with last persisted snapshot' do
+      beamer = create(:beamer, name: 'projector', display_state: 'between_games')
+      payload = nil
+
+      expect(BeamerBroadcast).to receive(:call) do |args|
+        payload = args.fetch(:payload)
+        expect(args.fetch(:beamer_names)).to eq(['projector'])
+      end
+
+      beamer.destroy!
+
+      expect(payload[:type]).to eq('beamer.deleted')
+      expect(payload.dig(:beamer, :name)).to eq('projector')
+      expect(payload.dig(:beamer, :display_state)).to eq('between_games')
+    end
+  end
 end