Allow to subscribe to specific resource. #16

lib/rest_redis_pub_sub.rb

@@ -2,6 +2,7 @@
 require "rest_redis_pub_sub/client"
 require "rest_redis_pub_sub/event_handler"
 require "rest_redis_pub_sub/helper"
+require "rest_redis_pub_sub/resource_subscriber"
 require "rest_redis_pub_sub/version"
 
 module RestRedisPubSub

lib/rest_redis_pub_sub/resource_subscriber.rb

@@ -0,0 +1,22 @@
+module RestRedisPubSub
+  class ResourceSubscriber
+    SUBSCRIPTION_KEY = 'subscriptions'
+
+    def initialize(attrs)
+       @app = attrs.fetch(:app)
+       @resource = attrs.fetch(:resource)
+       @id = attrs.fetch(:id)
+    end
+
+    attr_reader :app, :resource, :id
+
+    def subscribe
+      RestRedisPubSub.redis_instance.sadd(resource_key, RestRedisPubSub.publisher)
+    end
+
+    def resource_key
+      [SUBSCRIPTION_KEY, app, resource, id].join(':')
+    end
+
+  end
+end

spec/rest_redis_pub_sub/resource_subscriber_spec.rb

@@ -0,0 +1,40 @@
+require 'spec_helper'
+
+describe RestRedisPubSub::ResourceSubscriber do
+
+  describe "#initialize" do
+    it "should succeed if all required attrs are present" do
+      expect{
+        described_class.new(app: 'crushpath', resource: 'spot', id: 1234)
+      }.not_to raise_error
+    end
+
+    it "should fail if required attrs are missing" do
+      expect{
+        described_class.new(resource: 'spot', id: 1234)
+      }.to raise_error(KeyError)
+
+      expect{
+        described_class.new(app: 'crushpath', id: 1234)
+      }.to raise_error(KeyError)
+
+      expect{
+        described_class.new(app: 'crushpath', resource: 'spot')
+      }.to raise_error(KeyError)
+    end
+  end
+
+  describe "#resource_key" do
+    it "should return the correct key" do
+      subscriber = described_class.new(app: 'crushpath', resource: 'spot', id: 1234)
+      expect(subscriber.resource_key).to eq("subscriptions:crushpath:spot:1234")
+    end
+  end
+
+  describe "#subscribe" do
+    it "should add current app to the resource subscribers list" do
+
+    end
+  end
+
+end