allow multiple clients for the same id

app/controllers/api/v1/activity_log_controller.rb

@@ -33,7 +33,7 @@ class Api::V1::ActivityLogController < Api::BaseController
         sleep 10
       end
     ensure
-      ActivityLogger.unregister(id)
+      ActivityLogger.unregister(id, sse)
       sse.close
     end
   end

app/lib/activity_logger.rb

@@ -2,19 +2,21 @@
 
 class ActivityLogger
 
-  @@loggers = Hash.new
+  @@loggers = Hash.new { |hash, key| hash[key] = [] }
 
   def self.register(id, sse)
-    @@loggers[id] = sse
+    @@loggers[id] << sse
   end
 
-  def self.unregister(id)
-    @@loggers.delete(id)
+  def self.unregister(id, sse)
+    @@loggers[id].delete(sse)
   end
 
   def self.log(id, event)
-    if @@loggers[id]
-      @@loggers[id].write event
-    end
+    @@loggers[id].each { |logger| logger.write event }
+  end
+
+  def self.reset
+    @@loggers.clear
   end
 end

spec/lib/activity_logger_spec.rb

@@ -0,0 +1,58 @@
+require 'json'
+require 'rails_helper'
+
+def activity_log_event_fixture(name)
+  json_string = File.read(Rails.root.join('spec', 'fixtures', 'activity_log_events', name))
+
+  ActivityLogEvent.from_json_string(json_string)
+end
+
+RSpec.describe ActivityLogger do
+
+  after(:each) do
+    ActivityLogger.reset
+  end
+
+  describe 'log' do
+
+    it 'sends events to all listeners of the same id' do
+      sse1 = spy('sse1')
+      sse2 = spy('sse2')
+      event = double('event')
+
+      ActivityLogger.register('test_id', sse1)
+      ActivityLogger.register('test_id', sse2)
+
+      ActivityLogger.log('test_id', event)
+
+      expect(sse1).to have_received(:write).with(event)
+      expect(sse2).to have_received(:write).with(event)
+    end
+
+    it 'does not send events to listeners of a different id' do
+      sse = spy('sse')
+      event = double('event')
+
+      ActivityLogger.register('test_id', sse)
+
+      ActivityLogger.log('other_id', event)
+
+      expect(sse).to_not have_received(:write).with(event)
+    end
+
+    it 'does not send events to listeners after unregistering' do
+      sse1 = spy('sse1')
+      sse2 = spy('sse2')
+      event = double('event')
+
+      ActivityLogger.register('test_id', sse1)
+      ActivityLogger.register('test_id', sse2)
+      ActivityLogger.unregister('test_id', sse1)
+
+      ActivityLogger.log('test_id', event)
+
+      expect(sse1).to_not have_received(:write).with(event)
+      expect(sse2).to have_received(:write).with(event)
+    end
+  end
+end