Hash channel to have a more compact index

.rubocop.yml

@@ -11,6 +11,7 @@ AllCops:
     - test/dummy/**/*
     - bench/**/*
     - test/lib/action_cable/subscription_adapter/solid_cable_test.rb
+    - lib/generators/**/*_schema.rb
   TargetRubyVersion: 3.3
 
 # Department Bundler

README.md

@@ -45,6 +45,9 @@ production:
 
 Then run `db:prepare` in production to ensure the database is created and the schema is loaded.
 
+If you have already installed Solid Cable, run `solid_cable:update` to get the
+latest changes to migrations.
+
 ## Configuration
 
 All configuration is managed via the `config/cable.yml` file. By default, it'll be configured like this:

app/models/solid_cable/message.rb

@@ -6,7 +6,29 @@ class Message < SolidCable::Record
       where(created_at: ..::SolidCable.message_retention.ago)
     }
     scope :broadcastable, lambda { |channels, last_id|
-      where(channel: channels).where(id: (last_id + 1)..).order(:id)
+      where(channel_hash: channel_hashes_for(channels)).
+        where(id: (last_id + 1)..).order(:id)
     }
+
+    class << self
+      def broadcast(channel, payload)
+        attrs =
+          new(channel:, payload:, channel_hash: channel_hash_for(channel)).
+          attributes.
+          with_indifferent_access.except(:id, :created_at, :updated_at)
+
+        insert(attrs)
+      end
+
+      def channel_hashes_for(channels)
+        channels.map { |channel| channel_hash_for(channel) }
+      end
+
+      # Need to unpack this as a signed integer since Postgresql and SQLite
+      # don't support unsigned integers
+      def channel_hash_for(channel)
+        Digest::SHA256.digest(channel.to_s).unpack1("q>")
+      end
+    end
   end
 end

lib/action_cable/subscription_adapter/solid_cable.rb

@@ -15,7 +15,7 @@ def initialize(*)
       end
 
       def broadcast(channel, payload)
-        ::SolidCable::Message.insert({ channel:, payload: })
+        ::SolidCable::Message.broadcast(channel, payload)
       end
 
       def subscribe(channel, callback, success_callback = nil)

lib/generators/solid_cable/install/templates/db/cable_schema.rb

@@ -2,12 +2,13 @@
 
 ActiveRecord::Schema[7.1].define(version: 1) do
   create_table "solid_cable_messages", force: :cascade do |t|
-    t.text "channel"
-    t.text "payload"
+    t.binary "channel", limit: 1024, null: false
+    t.binary "payload", limit: 536870912, null: false
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
-    t.index ["channel"], name: "index_solid_cable_messages_on_channel",
-                         length: 500
+    t.integer "channel_hash", limit: 8, null: false
+    t.index ["channel"], name: "index_solid_cable_messages_on_channel"
+    t.index ["channel_hash"], name: "index_solid_cable_messages_on_channel_hash"
     t.index ["created_at"], name: "index_solid_cable_messages_on_created_at"
   end
 end

lib/generators/solid_cable/update/USAGE

@@ -0,0 +1,8 @@
+Description:
+    Updates Solid Cable migrations
+
+Example:
+    bin/rails generate solid_cable:update
+
+    This will perform the following:
+        Installs new Solid Cable migrations

lib/generators/solid_cable/update/templates/db/migrate/create_compact_channel.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class CreateCompactChannel < ActiveRecord::Migration[7.2]
+  def change
+    change_column :solid_cable_messages, :channel,
+                  :binary, limit: 1024, null: false
+    add_column :solid_cable_messages, :channel_hash,
+               :integer, limit: 8, null: false
+    add_index :solid_cable_messages, :channel_hash
+    change_column :solid_cable_messages, :payload,
+                  :binary, limit: 536_870_912, null: false
+  end
+end

lib/generators/solid_cable/update/update_generator.rb

@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+class SolidCable::UpdateGenerator < Rails::Generators::Base
+  source_root File.expand_path("templates", __dir__)
+
+  def copy_files
+    migration_template "db/migrate/create_compact_channel",
+                       "db/cable_migrate/create_compact_channel"
+  end
+end

lib/tasks/solid_cable_tasks.rake

@@ -5,4 +5,8 @@ namespace :solid_cable do
   task :install do
     Rails::Command.invoke :generate, ["solid_cable:install"]
   end
+
+  task :update do
+    Rails::Command.invoke :generate, ["solid_cable:update"]
+  end
 end

test/dummy/db/schema.rb

@@ -10,13 +10,15 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.2].define(version: 2024_08_23_212658) do
+ActiveRecord::Schema[7.2].define(version: 2024_09_12_130854) do
   create_table "solid_cable_messages", force: :cascade do |t|
-    t.text "channel"
-    t.text "payload"
+    t.binary "channel", limit: 1024, null: false
+    t.binary "payload", limit: 536870912, null: false
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.integer "channel_hash", limit: 8, null: false
     t.index ["channel"], name: "index_solid_cable_messages_on_channel"
+    t.index ["channel_hash"], name: "index_solid_cable_messages_on_channel_hash"
     t.index ["created_at"], name: "index_solid_cable_messages_on_created_at"
   end
 end