Cable: Generate .js or .coffee files while generating channel as per the javascript engine of the application

- Now we will detect what javascript engine user is using and based on
  that we will generate either `.js` or `.coffee` version of the channel
  file.
- This also needs a change in coffee-rails to override the `js_template`
  method. Related PR https://github.com/rails/coffee-rails/pull/72.
- Currently coffee-rails gem sets
  `config.app_generators.javascript_engine` to `:coffee` and using this
  information we override the `js_template` to set the extension as
  `.coffee` in coffee-rails gem.
- Using this approach, we can keep the `channel.js` and `channel.coffee`
  files in the Rails repository itself.
- Additionally the `js_template` method can act as public interface for
  coffee-rails gem to hook into and change the extension to `.coffee`
  without maintaining the actual asset files.

[Prathamesh Sonpatki, Matthew Draper]

2 files changed, 20 insertions, 1 deletions

diff --git a/actioncable/lib/rails/generators/channel/channel_generator.rb b/actioncable/lib/rails/generators/channel/channel_generator.rb
index 05fd21a954..47232252e3 100644
--- a/actioncable/lib/rails/generators/channel/channel_generator.rb
+++ b/actioncable/lib/rails/generators/channel/channel_generator.rb
@@ -16,7 +16,8 @@ module Rails
           if self.behavior == :invoke
             template "assets/cable.js", "app/assets/javascripts/cable.js"
           end
-          template "assets/channel.coffee", File.join('app/assets/javascripts/channels', class_path, "#{file_name}.coffee")
+
+          js_template "assets/channel", File.join('app/assets/javascripts/channels', class_path, "#{file_name}")
         end
 
         generate_application_cable_files
diff --git a/actioncable/lib/rails/generators/channel/templates/assets/channel.js b/actioncable/lib/rails/generators/channel/templates/assets/channel.js
new file mode 100644
index 0000000000..ab0e68b11a
--- /dev/null
+++ b/actioncable/lib/rails/generators/channel/templates/assets/channel.js
@@ -0,0 +1,18 @@
+App.<%= class_name.underscore %> = App.cable.subscriptions.create("<%= class_name %>Channel", {
+  connected: function() {
+    // Called when the subscription is ready for use on the server
+  },
+
+  disconnected: function() {
+    // Called when the subscription has been terminated by the server
+  },
+
+  received: function(data) {
+    // Called when there's incoming data on the websocket for this channel
+  }<%= actions.any? ? ",\n" : '' %>
+<% actions.each do |action| -%>
+  <%=action %>: function() {
+    return this.perform('<%= action %>');
+  }<%= action == actions[-1] ? '' : ",\n" %>
+<% end -%>
+});