Channel generator (#95)

* Generate channel and prepare JS file

* Inject stream identifier

* Generate stimulus controller from template

* Only generate stimulus controller if actually using stimulus

* Prepare a test helper

* Clarify usage

* Standardize

* Correct stream_for 🤦

* update cable_ready channel generator

The most important changes:

add class options

add tests

add default values for prompts

change generator name from `cable_ready_channel` to `cable_ready:channel`

* remove byebug require

* change channel generator to make more use of --stream-for and --stream-from

* add GitHub action to actually run the tests

Co-authored-by: Marco Roth <[email protected]>

.github/workflows/tests.yml

@@ -0,0 +1,36 @@
+name: Tests
+
+on:
+  pull_request:
+    branches:
+      - '*'
+  push:
+    branches:
+      - master
+
+jobs:
+  ruby_test:
+    name: Ruby Test Action
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        ruby-version: [2.6.6, 2.7.2, '3.0']
+    steps:
+    - uses: actions/checkout@master
+    - name: Set up Ruby ${{ matrix.ruby-version }}
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: ${{ matrix.ruby-version }}
+    - uses: actions/cache@v1
+      with:
+        path: vendor/bundle
+        key: ${{ runner.os }}-gems-${{ hashFiles('**/Gemfile.lock') }}
+        restore-keys: |
+          ${{ runner.os }}-gems-
+    - name: Bundle install
+      run: |
+        gem install bundler
+        bundle config path vendor/bundle
+        bundle install --jobs 4 --retry 3
+    - name: Run ruby tests
+      run: bundle exec rake test

.gitignore

@@ -8,3 +8,5 @@
 /spec/reports/
 /tmp/
 node_modules/
+*~
+.byebug_history

Gemfile.lock

@@ -105,11 +105,14 @@ GEM
     method_source (0.9.2)
     mimemagic (0.3.5)
     mini_mime (1.0.2)
+    mini_portile2 (2.5.0)
     minitest (5.14.3)
+    mocha (1.12.0)
     multi_json (1.15.0)
     multipart-post (2.1.1)
     nio4r (2.5.4)
-    nokogiri (1.11.1-x86_64-darwin)
+    nokogiri (1.11.1)
+      mini_portile2 (~> 2.5.0)
       racc (~> 1.4)
     octokit (4.20.0)
       faraday (>= 0.9)
@@ -206,6 +209,7 @@ DEPENDENCIES
   cable_ready!
   github_changelog_generator
   magic_frozen_string_literal
+  mocha
   pry
   pry-nav
   rake

Rakefile

@@ -2,11 +2,17 @@
 
 require "bundler/gem_tasks"
 require "github_changelog_generator/task"
+require "rake/testtask"
+require "pry"
 
 task default: [:test]
 
-task :test do
-  puts "Please write some tests..."
+Rake::TestTask.new(:test) do |t|
+  t.libs << "lib"
+  t.libs << "test"
+  t.pattern = "test/**/*_test.rb"
+  t.verbose = true
+  t.warning = false
 end
 
 GitHubChangelogGenerator::RakeTask.new :changelog do |config|

cable_ready.gemspec

@@ -23,4 +23,5 @@ Gem::Specification.new do |gem|
   gem.add_development_dependency "pry-nav"
   gem.add_development_dependency "rake"
   gem.add_development_dependency "standardrb"
+  gem.add_development_dependency "mocha"
 end

lib/generators/cable_ready/USAGE

@@ -0,0 +1,10 @@
+Description:
+  Create an ActionCable channel ready for usage with CableReady
+
+Example:
+  bin/rails generate cable_ready:channel Thing
+
+  This will create:
+    app/channels/thing_channel.rb
+    app/javascript/channels/thing_channel.js
+    app/javascript/controllers/thing_controller.js (Optional)

lib/generators/cable_ready/channel_generator.rb

@@ -0,0 +1,71 @@
+# frozen_string_literal: true
+
+class CableReady::ChannelGenerator < Rails::Generators::NamedBase
+  source_root File.expand_path("templates", __dir__)
+
+  class_option :stream_from, type: :string
+  class_option :stream_for, type: :string
+  class_option :stimulus, type: :boolean
+
+  def check_options
+    raise "Can't specify --stream-from and --stream-for at the same time" if options.key?(:stream_from) && options.key?(:stream_for)
+  end
+
+  def create_channel
+    generate "channel", file_name
+  end
+
+  def enhance_channels
+    if using_broadcast_to?
+      gsub_file "app/channels/#{file_name}_channel.rb", /# stream_from.*\n/, "stream_for #{resource}.find(params[:id])\n"
+      template "app/javascript/controllers/%file_name%_controller.js" if using_stimulus?
+    else
+      prepend_to_file "app/javascript/channels/#{file_name}_channel.js", "import CableReady from 'cable_ready'\n"
+      inject_into_file "app/javascript/channels/#{file_name}_channel.js", after: "// Called when there's incoming data on the websocket for this channel\n" do
+        <<-JS
+    if (data.cableReady) CableReady.perform(data.operations)
+        JS
+      end
+
+      gsub_file "app/channels/#{file_name}_channel.rb", /# stream_from.*\n/, "stream_from \"#{identifier}\"\n"
+    end
+  end
+
+  private
+
+  def option_given?
+    options.key?(:stream_from) || options.key?(:stream_for)
+  end
+
+  def using_broadcast_to?
+    @using_broadcast_to ||= option_given? ? options.key?(:stream_for) : yes?("Are you streaming to a resource using broadcast_to? (y/N)")
+  end
+
+  def using_stimulus?
+    @using_stimulus ||= options.fetch(:stimulus) {
+      yes?("Are you going to use a Stimulus controller to subscribe to this channel? (y/N)")
+    }
+  end
+
+  def resource
+    return @resource if @resource
+
+    stream_for = options.fetch(:stream_for) {
+      ask("Which resource are you streaming for?", default: class_name)
+    }
+
+    stream_for = file_name if stream_for == "stream_for"
+    @resource = stream_for.camelize
+  end
+
+  def identifier
+    return @identifier if @identifier
+
+    stream_from = options.fetch(:stream_from) {
+      ask("What is the stream identifier that goes into stream_from?", default: file_name)
+    }
+
+    stream_from = file_name if stream_from == "stream_from"
+    @identifier = stream_from.underscore
+  end
+end

lib/generators/cable_ready/templates/app/javascript/controllers/%file_name%_controller.js.tt

@@ -0,0 +1,21 @@
+import { Controller } from 'stimulus'
+import CableReady from 'cable_ready'
+
+export default class extends Controller {
+  static values = { id: Number }
+
+  connect() {
+    this.channel = this.application.consumer.subscriptions.create({
+      channel: '<%= class_name %>Channel',
+      id: this.idValue
+    }, {
+      received (data) {
+        if (data.cableReady) CableReady.perform(data.operations)
+      }
+    })
+  }
+
+  disconnect() {
+    this.channel.unsubscribe()
+  }
+}

test/lib/generators/cable_ready/channel_generator_test.rb

@@ -0,0 +1,157 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "generators/cable_ready/channel_generator"
+
+class CableReady::ChannelGeneratorTest < Rails::Generators::TestCase
+  include ::GeneratorTestHelpers
+
+  tests CableReady::ChannelGenerator
+  destination File.expand_path("../../../../tmp/dummy", __dir__)
+
+  prepare_destination
+  create_sample_app
+
+  MiniTest.after_run do
+    remove_sample_app
+  end
+
+  test "should generate channel with the same resource name and stimulus controller" do
+    run_generator ["user", "--stream-for=user", "--stimulus"]
+
+    assert_file "app/channels/user_channel.rb" do |content|
+      assert_match(/class\ UserChannel\ </, content)
+      assert_match(/stream_for\ User\.find\(params\[:id\]\)/, content)
+    end
+
+    assert_file "app/javascript/channels/user_channel.js", /"UserChannel"/
+    assert_file "app/javascript/controllers/user_controller.js", /'UserChannel'/
+  end
+
+  test "should generate channel with different resource name" do
+    run_generator ["my_name", "--stream-for=under_scored_resource_name", "--no-stimulus"]
+
+    assert_file "app/channels/my_name_channel.rb" do |content|
+      assert_match(/class\ MyNameChannel\ </, content)
+      assert_match(/stream_for\ UnderScoredResourceName\.find\(params\[:id\]\)/, content)
+    end
+
+    assert_file "app/javascript/channels/my_name_channel.js", /"MyNameChannel"/
+    assert_no_file "app/javascript/controllers/my_name_controller.js"
+  end
+
+  test "should not generate stimulus controller if not requested" do
+    run_generator ["comment", "--stream-for=comment", "--no-stimulus"]
+
+    assert_file "app/channels/comment_channel.rb"
+    assert_file "app/javascript/channels/comment_channel.js"
+    assert_no_file "app/javascript/controllers/comment_controller.js"
+  end
+
+  test "should run the generator when streaming from identifier" do
+    run_generator ["page", "--stream-from=page"]
+
+    assert_file "app/channels/page_channel.rb" do |content|
+      assert_match(/PageChannel/, content)
+      assert_match(/stream_from\ "page"/, content)
+    end
+
+    assert_file "app/javascript/channels/page_channel.js" do |content|
+      assert_match(/"PageChannel"/, content)
+      assert_match(/import\ CableReady/, content)
+      assert_match(/if\ \(data\.cableReady\)\ CableReady\.perform\(data\.operations\)/, content)
+    end
+  end
+
+  test "should run the generator when streaming without resource and different identifier" do
+    run_generator ["my_page", "--stream-from=ThisIsMyPage"]
+
+    assert_file "app/channels/my_page_channel.rb" do |content|
+      assert_match(/MyPageChannel/, content)
+      assert_match(/stream_from\ "this_is_my_page"/, content)
+    end
+
+    assert_file "app/javascript/channels/my_page_channel.js" do |content|
+      assert_match(/"MyPageChannel"/, content)
+      assert_match(/import\ CableReady/, content)
+      assert_match(/if\ \(data\.cableReady\)\ CableReady\.perform\(data\.operations\)/, content)
+    end
+  end
+
+  test "should run the generator and use the NAME for --stream-from if nothing passed" do
+    run_generator ["house", "--stream-from"]
+
+    assert_file "app/channels/house_channel.rb" do |content|
+      assert_match(/HouseChannel/, content)
+      assert_match(/stream_from\ "house"/, content)
+    end
+
+    assert_file "app/javascript/channels/house_channel.js" do |content|
+      assert_match(/"HouseChannel"/, content)
+      assert_match(/import\ CableReady/, content)
+      assert_match(/if\ \(data\.cableReady\)\ CableReady\.perform\(data\.operations\)/, content)
+    end
+  end
+
+  test "should run the generator and use the NAME for --stream-for if nothing passed" do
+    run_generator ["option", "--stream-for", "--stimulus"]
+
+    assert_file "app/channels/option_channel.rb" do |content|
+      assert_match(/class\ OptionChannel\ </, content)
+      assert_match(/stream_for\ Option\.find\(params\[:id\]\)/, content)
+    end
+
+    assert_file "app/javascript/channels/option_channel.js", /"OptionChannel"/
+    assert_file "app/javascript/controllers/option_controller.js", /'OptionChannel'/
+  end
+
+  test "should run not generate anything if passed stream_from and stream_for" do
+    assert_raises "Can't specify --stream-from and --stream-for at the same time" do
+      run_generator ["error", "--stream-from=1", "--stream-for=2"]
+    end
+  end
+
+  # some tests without generator options to simulate the inputs passed via cli
+
+  test "should generate channel with the same resource name and stimulus controller (without options)" do
+    CableReady::ChannelGenerator.any_instance.stubs(:using_broadcast_to?).returns(true)
+    CableReady::ChannelGenerator.any_instance.stubs(:resource).returns("Post")
+    CableReady::ChannelGenerator.any_instance.stubs(:using_stimulus?).returns(true)
+
+    run_generator ["post"]
+
+    assert_file "app/channels/post_channel.rb" do |content|
+      assert_match(/class\ PostChannel\ </, content)
+      assert_match(/stream_for\ Post\.find\(params\[:id\]\)/, content)
+    end
+
+    assert_file "app/javascript/channels/post_channel.js", /PostChannel/
+    assert_file "app/javascript/controllers/post_controller.js", /'PostChannel'/
+  end
+
+  test "should not generate stimulus controller if not requested (without options)" do
+    CableReady::ChannelGenerator.any_instance.stubs(:using_broadcast_to?).returns(true)
+    CableReady::ChannelGenerator.any_instance.stubs(:resource).returns("Admin")
+    CableReady::ChannelGenerator.any_instance.stubs(:using_stimulus?).returns(false)
+
+    run_generator ["admin"]
+
+    assert_file "app/channels/admin_channel.rb"
+    assert_file "app/javascript/channels/admin_channel.js"
+    assert_no_file "app/javascript/controllers/admin_controller.js"
+  end
+
+  test "should run the generator when streaming from identifier (without options)" do
+    CableReady::ChannelGenerator.any_instance.stubs(:using_broadcast_to?).returns(false)
+    CableReady::ChannelGenerator.any_instance.stubs(:identifier).returns("index_identifier")
+
+    run_generator ["index"]
+
+    assert_file "app/channels/index_channel.rb" do |content|
+      assert_match(/IndexChannel/, content)
+      assert_match(/stream_from\ "index_identifier"/, content)
+    end
+
+    assert_file "app/javascript/channels/index_channel.js", /"IndexChannel"/
+  end
+end

test/support/generator_test_helpers.rb

@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+module GeneratorTestHelpers
+  def self.included(base)
+    base.extend ClassMethods
+  end
+
+  module ClassMethods
+    def sample_app_path
+      File.expand_path("../../tmp/dummy", __dir__)
+    end
+
+    def prepare_destination
+      FileUtils.rm_rf(sample_app_path) if Dir.exist?(sample_app_path)
+      FileUtils.mkdir_p(sample_app_path)
+    end
+
+    def create_sample_app
+      FileUtils.cd(sample_app_path) do
+        system "rails new . --minimal --skip-active-record --skip-test-unit --skip-spring --skip-bundle --quiet --force"
+      end
+    end
+
+    def remove_sample_app
+      FileUtils.rm_rf(destination_root)
+    end
+  end
+end