From 173e606f0e096be2a285880144ddc7b2f5bad6c5 Mon Sep 17 00:00:00 2001
From: "Gregory N. Schmit" <schmitgreg@gmail.com>
Date: Wed, 7 Dec 2022 01:49:30 -0600
Subject: [PATCH 1/2] Initial work on building websockets API from rest
 controllers.

---
 .gitignore                                    |  1 +
 Gemfile                                       |  8 ++--
 Gemfile.lock                                  | 13 ++++++-
 lib/rest_framework/controller_mixins/base.rb  | 38 +++++++++----------
 .../controller_mixins/models.rb               | 13 ++++---
 lib/rest_framework/serializers.rb             |  2 +-
 test/Procfile                                 |  3 ++
 .../app/channels/application_cable/channel.rb |  4 ++
 .../channels/application_cable/connection.rb  |  9 +++++
 test/app/channels/test_channel.rb             |  9 +++++
 .../controllers/demo_api/things_controller.rb | 32 ++++++++++++++++
 test/config/application.rb                    |  3 ++
 test/config/cable.yml                         | 12 ++++++
 13 files changed, 115 insertions(+), 32 deletions(-)
 create mode 100644 test/Procfile
 create mode 100644 test/app/channels/application_cable/channel.rb
 create mode 100644 test/app/channels/application_cable/connection.rb
 create mode 100644 test/app/channels/test_channel.rb
 create mode 100644 test/config/cable.yml

diff --git a/.gitignore b/.gitignore
index 55c49e8..debb5e3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,6 @@
 VERSION
 coverage
+dump.rdb
 
 # Created by https://www.toptal.com/developers/gitignore/api/ruby,rails,macos,windows,linux,vim,emacs
 # Edit at https://www.toptal.com/developers/gitignore?templates=ruby,rails,macos,windows,linux,vim,emacs
diff --git a/Gemfile b/Gemfile
index ee51326..c53dfa4 100644
--- a/Gemfile
+++ b/Gemfile
@@ -10,11 +10,8 @@ RAILS_VERSION = Gem::Version.new(
 )
 gem "rails", "~> #{RAILS_VERSION}"
 gem "rake", ">= 12.0"
-
-# Ruby 3 removed webrick, so we need to install it manually.
-if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new("3")
-  gem "webrick"
-end
+gem "puma"
+gem "redis"
 
 # Include gem active_model_serializers so we can test against their interface (Rails >=6 only).
 if RAILS_VERSION > Gem::Version.new("6")
@@ -25,6 +22,7 @@ group :development do
   gem "better_errors"
   gem "binding_of_caller"
   gem "byebug"
+  gem "foreman"
   gem "pry-rails"
   gem "rubocop-shopify", require: false
   gem "web-console"
diff --git a/Gemfile.lock b/Gemfile.lock
index 84ae1ff..a5feef9 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -91,6 +91,7 @@ GEM
       activesupport
     coderay (1.1.3)
     concurrent-ruby (1.1.10)
+    connection_pool (2.3.0)
     coveralls (0.8.23)
       json (>= 1.8, < 3)
       simplecov (~> 0.16.1)
@@ -101,6 +102,7 @@ GEM
     debug_inspector (1.1.0)
     docile (1.4.0)
     erubi (1.11.0)
+    foreman (0.87.2)
     globalid (1.0.0)
       activesupport (>= 5.0)
     i18n (1.12.0)
@@ -138,6 +140,8 @@ GEM
       method_source (~> 1.0)
     pry-rails (0.3.9)
       pry (>= 0.10.4)
+    puma (6.0.0)
+      nio4r (~> 2.0)
     racc (1.6.0)
     rack (2.2.4)
     rack-test (2.0.2)
@@ -170,6 +174,10 @@ GEM
       zeitwerk (~> 2.5)
     rainbow (3.1.1)
     rake (13.0.6)
+    redis (5.0.5)
+      redis-client (>= 0.9.0)
+    redis-client (0.11.2)
+      connection_pool
     regexp_parser (2.6.0)
     rexml (3.2.5)
     rubocop (1.38.0)
@@ -208,7 +216,6 @@ GEM
       activemodel (>= 6.0.0)
       bindex (>= 0.4.0)
       railties (>= 6.0.0)
-    webrick (1.7.0)
     websocket-driver (0.7.5)
       websocket-extensions (>= 0.1.0)
     websocket-extensions (0.1.5)
@@ -223,16 +230,18 @@ DEPENDENCIES
   binding_of_caller
   byebug
   coveralls
+  foreman
   minitest (>= 5.0)
   pg
   pry-rails
+  puma
   rails (~> 7.0.4)
   rake (>= 12.0)
+  redis
   rest_framework!
   rubocop-shopify
   sqlite3 (~> 1.4.0)
   web-console
-  webrick
 
 BUNDLED WITH
    2.2.33
diff --git a/lib/rest_framework/controller_mixins/base.rb b/lib/rest_framework/controller_mixins/base.rb
index 1477f07..d3c23d6 100644
--- a/lib/rest_framework/controller_mixins/base.rb
+++ b/lib/rest_framework/controller_mixins/base.rb
@@ -26,6 +26,24 @@ def get_skip_actions(skip_undefined: true)
 
       return skip
     end
+
+    # Get the configured serializer class.
+    def get_serializer_class
+      return nil unless serializer_class = self.serializer_class
+
+      # Support dynamically resolving serializer given a symbol or string.
+      serializer_class = serializer_class.to_s if serializer_class.is_a?(Symbol)
+      if serializer_class.is_a?(String)
+        serializer_class = self.const_get(serializer_class)
+      end
+
+      # Wrap it with an adapter if it's an active_model_serializer.
+      if defined?(ActiveModel::Serializer) && (serializer_class < ActiveModel::Serializer)
+        serializer_class = RESTFramework::ActiveModelSerializerAdapterFactory.for(serializer_class)
+      end
+
+      return serializer_class
+    end
   end
 
   def self.included(base)
@@ -92,27 +110,9 @@ def self.included(base)
     end
   end
 
-  # Helper to get the configured serializer class.
-  def get_serializer_class
-    return nil unless serializer_class = self.class.serializer_class
-
-    # Support dynamically resolving serializer given a symbol or string.
-    serializer_class = serializer_class.to_s if serializer_class.is_a?(Symbol)
-    if serializer_class.is_a?(String)
-      serializer_class = self.class.const_get(serializer_class)
-    end
-
-    # Wrap it with an adapter if it's an active_model_serializer.
-    if defined?(ActiveModel::Serializer) && (serializer_class < ActiveModel::Serializer)
-      serializer_class = RESTFramework::ActiveModelSerializerAdapterFactory.for(serializer_class)
-    end
-
-    return serializer_class
-  end
-
   # Helper to serialize data using the `serializer_class`.
   def serialize(data, **kwargs)
-    return self.get_serializer_class.new(data, controller: self, **kwargs).serialize
+    return self.class.get_serializer_class.new(data, controller: self, **kwargs).serialize
   end
 
   # Helper to get filtering backends, defaulting to no backends.
diff --git a/lib/rest_framework/controller_mixins/models.rb b/lib/rest_framework/controller_mixins/models.rb
index 5ecb4cd..fe55f7a 100644
--- a/lib/rest_framework/controller_mixins/models.rb
+++ b/lib/rest_framework/controller_mixins/models.rb
@@ -5,9 +5,17 @@
 module RESTFramework::BaseModelControllerMixin
   include RESTFramework::BaseControllerMixin
 
+  module ClassMethods
+    # Get the configured serializer class, or `NativeSerializer` as a default.
+    def get_serializer_class
+      return super || RESTFramework::NativeSerializer
+    end
+  end
+
   def self.included(base)
     if base.is_a?(Class)
       RESTFramework::BaseControllerMixin.included(base)
+      base.extend(ClassMethods)
 
       # Add class attributes (with defaults) unless they already exist.
       {
@@ -109,11 +117,6 @@ def get_allowed_parameters
     ) || self.fields
   end
 
-  # Helper to get the configured serializer class, or `NativeSerializer` as a default.
-  def get_serializer_class
-    return super || RESTFramework::NativeSerializer
-  end
-
   # Helper to get filtering backends, defaulting to using `ModelFilter` and `ModelOrderingFilter`.
   def get_filter_backends
     return self.class.filter_backends || [
diff --git a/lib/rest_framework/serializers.rb b/lib/rest_framework/serializers.rb
index 4e63c28..a8ec477 100644
--- a/lib/rest_framework/serializers.rb
+++ b/lib/rest_framework/serializers.rb
@@ -248,7 +248,7 @@ def _serialize(record, config, serializer_methods)
     )
   end
 
-  def serialize(*args)
+  def serialize(*_args)
     config = self.get_serializer_config
     serializer_methods = config.delete(:serializer_methods)
 
diff --git a/test/Procfile b/test/Procfile
new file mode 100644
index 0000000..f230ec2
--- /dev/null
+++ b/test/Procfile
@@ -0,0 +1,3 @@
+# This Procfile is for running the test app on development systems.
+rails: bin/rails server
+redis: redis-server
diff --git a/test/app/channels/application_cable/channel.rb b/test/app/channels/application_cable/channel.rb
new file mode 100644
index 0000000..d672697
--- /dev/null
+++ b/test/app/channels/application_cable/channel.rb
@@ -0,0 +1,4 @@
+module ApplicationCable
+  class Channel < ActionCable::Channel::Base
+  end
+end
diff --git a/test/app/channels/application_cable/connection.rb b/test/app/channels/application_cable/connection.rb
new file mode 100644
index 0000000..288f223
--- /dev/null
+++ b/test/app/channels/application_cable/connection.rb
@@ -0,0 +1,9 @@
+module ApplicationCable
+  class Connection < ActionCable::Connection::Base
+    identified_by :random_token
+
+    def connect
+      self.random_token = SecureRandom.hex(4)
+    end
+  end
+end
diff --git a/test/app/channels/test_channel.rb b/test/app/channels/test_channel.rb
new file mode 100644
index 0000000..9a91d82
--- /dev/null
+++ b/test/app/channels/test_channel.rb
@@ -0,0 +1,9 @@
+class TestChannel < ApplicationCable::Channel
+  def subscribed
+    # stream_from "some_channel"
+  end
+
+  def unsubscribed
+    # Any cleanup needed when channel is unsubscribed
+  end
+end
diff --git a/test/app/controllers/demo_api/things_controller.rb b/test/app/controllers/demo_api/things_controller.rb
index 555e403..8b3d746 100644
--- a/test/app/controllers/demo_api/things_controller.rb
+++ b/test/app/controllers/demo_api/things_controller.rb
@@ -13,4 +13,36 @@ def toggle_is_discounted
     thing.update!(is_discounted: !thing.is_discounted)
     return api_response({message: "Is discounted toggled to #{thing.is_discounted}."})
   end
+
+  class Channel < ApplicationCable::Channel
+    # Subscribe with:
+    # {"command": "subscribe","identifier": "{\"channel\": \"DemoApi::ThingsController::Channel\"}"}
+    def subscribed
+      logger.info("GNS: subscribed")
+      stream_from("demo_api/things")
+    end
+
+    def index(_data)
+      controller = self._controller.new
+      controller.request = ActionDispatch::Request.new({})
+      controller.request.format
+      controller.index
+      ActionCable.server.broadcast(
+        "demo_api/things",
+        self._controller.get_serializer_class.new(self._controller.get_recordset).serialize,
+      )
+    end
+
+    def _controller
+      return self.class.to_s.deconstantize.constantize
+    end
+  end
+
+  this_controller = self
+  Thing.after_commit do
+    ActionCable.server.broadcast(
+      "demo_api/things",
+      this_controller.get_serializer_class.new(self).serialize,
+    )
+  end
 end
diff --git a/test/config/application.rb b/test/config/application.rb
index a5b0ed1..53dbc67 100644
--- a/test/config/application.rb
+++ b/test/config/application.rb
@@ -8,6 +8,7 @@
   "action_controller/railtie",
   "action_view/railtie",
   "active_job/railtie",
+  "action_cable/engine",
   "rails/test_unit/railtie",
 ].each do |railtie|
   require railtie
@@ -34,6 +35,8 @@ class Application < Rails::Application
   config.cache_classes = false
   config.action_controller.perform_caching = false
 
+  config.action_cable.disable_request_forgery_protection = true
+
   if Rails::VERSION::MAJOR >= 7
     config.active_support.remove_deprecated_time_with_zone_name = true
   end
diff --git a/test/config/cable.yml b/test/config/cable.yml
new file mode 100644
index 0000000..262ee3c
--- /dev/null
+++ b/test/config/cable.yml
@@ -0,0 +1,12 @@
+development:
+  adapter: redis
+  url: redis://localhost:6379
+  channel_prefix: rails_rest_framework_development
+
+test:
+  adapter: test
+
+production:
+  adapter: redis
+  url: redis://localhost:6379
+  channel_prefix: rails_rest_framework_production

From 38a91a399341ed927e62b9edc892a087f542643b Mon Sep 17 00:00:00 2001
From: "Gregory N. Schmit" <schmitgreg@gmail.com>
Date: Mon, 19 Dec 2022 11:16:57 -0600
Subject: [PATCH 2/2] more websockets demo/testing

---
 .../controller_mixins/channels.rb             | 18 ++++++++++++++++
 .../controllers/demo_api/things_controller.rb | 21 +++++++++++++------
 2 files changed, 33 insertions(+), 6 deletions(-)
 create mode 100644 lib/rest_framework/controller_mixins/channels.rb

diff --git a/lib/rest_framework/controller_mixins/channels.rb b/lib/rest_framework/controller_mixins/channels.rb
new file mode 100644
index 0000000..6c80da2
--- /dev/null
+++ b/lib/rest_framework/controller_mixins/channels.rb
@@ -0,0 +1,18 @@
+require_relative "models"
+
+# This module extends the base REST controller to support Action Cable Channels. If the controller
+# is associated to a specific model, then we can even support broadcasting table/record updates.
+#
+# The general idea is to dynamically construct a namespaced `::Channel` class to implement the
+# channel functionality.
+#
+# For controllers associated to models, we will support 2 types of updates:
+#  - Table Updates: Table updates will notify the subscriber when ANY record of a table is modified,
+#    whether it's a create, update, or delete. The notification will not include details on the
+#    specific record or records affected.
+#  - Record Updates: Record updates will notify the subscriber when a record is created, updated, or
+#    deleted, and will include the entire record and the action that was performed.
+#    TODO: this must be constrained to the records in `get_recordset`.
+#
+module RESTFramework::ChannelControllerMixin
+end
diff --git a/test/app/controllers/demo_api/things_controller.rb b/test/app/controllers/demo_api/things_controller.rb
index 8b3d746..2bcb7c9 100644
--- a/test/app/controllers/demo_api/things_controller.rb
+++ b/test/app/controllers/demo_api/things_controller.rb
@@ -39,10 +39,19 @@ def _controller
   end
 
   this_controller = self
-  Thing.after_commit do
-    ActionCable.server.broadcast(
-      "demo_api/things",
-      this_controller.get_serializer_class.new(self).serialize,
-    )
-  end
+  Thing.define_method(:bcast) {
+    if self.in?(controller.get_recordset)
+      ActionCable.server.broadcast(
+        "demo_api/things",
+        this_controller.get_serializer_class.new(self).serialize,
+      )
+    end
+  }
+  Thing.after_commit(:bcast)
+  # Thing.after_commit do
+  #   ActionCable.server.broadcast(
+  #     "demo_api/things",
+  #     this_controller.get_serializer_class.new(self).serialize,
+  #   )
+  # end
 end