From 238179db5d58c8ccc15757a5590a68c8119c38ee Mon Sep 17 00:00:00 2001
From: Khoa Nguyen <khoa@nguyen.com>
Date: Thu, 3 Aug 2023 17:36:31 +1000
Subject: [PATCH] add callback method in controller when auto include filter
 decides not to insert javascript

---
 README.md                                 |  8 ++++++++
 lib/intercom-rails/auto_include_filter.rb | 18 ++++++++++++++++--
 lib/intercom-rails/config.rb              |  1 +
 spec/auto_include_filter_spec.rb          |  7 +++++++
 spec/config_spec.rb                       |  5 +++++
 5 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 2e3d8a7..5508e4c 100644
--- a/README.md
+++ b/README.md
@@ -277,6 +277,14 @@ By default Intercom will be automatically inserted in development and production
   config.enabled_environments = ["production"]
 ```
 
+### Controller callback
+
+When using automatic insertion of Intercom Javascript, you can have a callback method in your controller should the criteria to automatically insert javascript is unmet. The callback is `intercom_javascript_excluded` by default, but you can configure to a more appropriate name for all controllers in your application.
+
+```ruby
+  config.exclude_javascript_callback = :intercom_javascript_excluded
+```
+
 ### Manually Inserting the Intercom Javascript
 
 Some situations may require manually inserting the Intercom script tag. If you simply wish to place the Intercom javascript in a different place within the page or, on a page without a closing `</body>` tag:
diff --git a/lib/intercom-rails/auto_include_filter.rb b/lib/intercom-rails/auto_include_filter.rb
index fdb30ed..65a9060 100644
--- a/lib/intercom-rails/auto_include_filter.rb
+++ b/lib/intercom-rails/auto_include_filter.rb
@@ -15,10 +15,14 @@ class Filter
 
       def self.filter(controller)
         return if BLOCKED_CONTROLLER_NAMES.include?(controller.class.name)
+
         auto_include_filter = new(controller)
-        return unless auto_include_filter.include_javascript?
 
-        auto_include_filter.include_javascript!
+        if auto_include_filter.include_javascript?
+          auto_include_filter.include_javascript!
+        else
+          auto_include_filter.exclude_javascript
+        end
 
         # User defined method to whitelist the script sha-256 when using CSP
         if defined?(CoreExtensions::IntercomRails::AutoInclude.csp_sha256_hook) == 'method'
@@ -44,6 +48,11 @@ def include_javascript?
         intercom_script_tag.valid?
       end
 
+      def exclude_javascript
+        callback = exclude_javascript_callback
+        controller.send(callback) if controller.respond_to?(callback)
+      end
+
       def csp_sha256
         intercom_script_tag.csp_sha256
       end
@@ -89,6 +98,11 @@ def show_everywhere?
         IntercomRails.config.include_for_logged_out_users
       end
 
+      def exclude_javascript_callback
+        IntercomRails.config.exclude_javascript_callback ||
+          :intercom_javascript_excluded
+      end
+
       def enabled_for_environment?
         enabled_environments = IntercomRails.config.enabled_environments
         return true if enabled_environments.nil?
diff --git a/lib/intercom-rails/config.rb b/lib/intercom-rails/config.rb
index 1093b2d..4340e82 100644
--- a/lib/intercom-rails/config.rb
+++ b/lib/intercom-rails/config.rb
@@ -110,6 +110,7 @@ def self.reset!
     config_accessor :hide_default_launcher
     config_accessor :api_base
     config_accessor :encrypted_mode
+    config_accessor :exclude_javascript_callback
 
     def self.api_key=(*)
       warn "Setting an Intercom API key is no longer supported; remove the `config.api_key = ...` line from config/initializers/intercom.rb"
diff --git a/spec/auto_include_filter_spec.rb b/spec/auto_include_filter_spec.rb
index aec9a0e..c7b177a 100644
--- a/spec/auto_include_filter_spec.rb
+++ b/spec/auto_include_filter_spec.rb
@@ -255,4 +255,11 @@ def current_user
       expect(response.body).to include('nonce="aaaa"')
     end
   end
+
+  context 'when intercom script is not injected' do
+    it 'invokes callback on controller' do
+      expect(controller).to receive(:intercom_javascript_excluded)
+      get :without_user
+    end
+  end
 end
diff --git a/spec/config_spec.rb b/spec/config_spec.rb
index c84fd26..d573088 100644
--- a/spec/config_spec.rb
+++ b/spec/config_spec.rb
@@ -66,6 +66,11 @@
     expect(IntercomRails.config.encrypted_mode).to eq(true)
   end
 
+  it 'gets/sets controller callback' do
+    IntercomRails.config.exclude_javascript_callback = :callback
+    expect(IntercomRails.config.exclude_javascript_callback).to eq(:callback)
+  end
+
   it 'raises error if current user not a proc' do
     expect { IntercomRails.config.user.current = 1 }.to raise_error(ArgumentError)
   end