FIX: properly cache user locale (#593)

This blob is localized according to user locale, so we can end up
bleeding incorrect data in the cache

app/models/ai_persona.rb

@@ -31,38 +31,8 @@ class AiPersona < ActiveRecord::Base
 
   before_update :regenerate_rag_fragments
 
-  class MultisiteHash
-    def initialize(id)
-      @hash = Hash.new { |h, k| h[k] = {} }
-      @id = id
-
-      MessageBus.subscribe(channel_name) { |message| @hash[message.data] = {} }
-    end
-
-    def channel_name
-      "/multisite-hash-#{@id}"
-    end
-
-    def current_db
-      RailsMultisite::ConnectionManagement.current_db
-    end
-
-    def [](key)
-      @hash.dig(current_db, key)
-    end
-
-    def []=(key, val)
-      @hash[current_db][key] = val
-    end
-
-    def flush!
-      @hash[current_db] = {}
-      MessageBus.publish(channel_name, current_db)
-    end
-  end
-
   def self.persona_cache
-    @persona_cache ||= MultisiteHash.new("persona_cache")
+    @persona_cache ||= ::DiscourseAi::MultisiteHash.new("persona_cache")
   end
 
   scope :ordered, -> { order("priority DESC, lower(name) ASC") }

lib/ai_helper/assistant.rb

@@ -3,16 +3,20 @@
 module DiscourseAi
   module AiHelper
     class Assistant
-      AI_HELPER_PROMPTS_CACHE_KEY = "ai_helper_prompts"
+      def self.prompt_cache
+        @prompt_cache ||= ::DiscourseAi::MultisiteHash.new("prompt_cache")
+      end
 
       def self.clear_prompt_cache!
-        Discourse.cache.delete(AI_HELPER_PROMPTS_CACHE_KEY)
+        prompt_cache.flush!
       end
 
       def available_prompts
-        Discourse
+        key = "prompt_cache_#{I18n.locale}"
-          .cache
+        self
-          .fetch(AI_HELPER_PROMPTS_CACHE_KEY, expires_in: 30.minutes) do
+          .class
+          .prompt_cache
+          .fetch(key) do
             prompts = CompletionPrompt.where(enabled: true)
 
             # Hide illustrate_post if disabled

lib/multisite_hash.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+module DiscourseAi
+  class MultisiteHash
+    def initialize(id)
+      @hash = Hash.new { |h, k| h[k] = {} }
+      @id = id
+
+      MessageBus.subscribe(channel_name) { |message| @hash[message.data] = {} }
+    end
+
+    def channel_name
+      "/multisite-hash-#{@id}"
+    end
+
+    def current_db
+      RailsMultisite::ConnectionManagement.current_db
+    end
+
+    def fetch(key)
+      @hash[current_db][key] ||= yield
+    end
+
+    def [](key)
+      @hash.dig(current_db, key)
+    end
+
+    def []=(key, val)
+      @hash[current_db][key] = val
+    end
+
+    def flush!
+      @hash[current_db] = {}
+      MessageBus.publish(channel_name, current_db)
+    end
+
+    # TODO implement a GC so we don't retain too much memory
+  end
+end

spec/lib/modules/ai_helper/entry_point_spec.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+describe DiscourseAi::AiHelper::EntryPoint do
+  fab!(:english_user) { Fabricate(:user) }
+  fab!(:french_user) { Fabricate(:user, locale: "fr") }
+
+  it "will correctly localize available prompts" do
+    SiteSetting.ai_helper_model = "fake:fake"
+    SiteSetting.default_locale = "en"
+    SiteSetting.allow_user_locale = true
+    SiteSetting.composer_ai_helper_enabled = true
+    SiteSetting.ai_helper_allowed_groups = "10" # tl0
+    DiscourseAi::AiHelper::Assistant.clear_prompt_cache!
+
+    Group.refresh_automatic_groups!
+
+    serializer = CurrentUserSerializer.new(english_user, scope: Guardian.new(english_user))
+    parsed = JSON.parse(serializer.to_json)
+
+    translate_prompt =
+      parsed["current_user"]["ai_helper_prompts"].find { |prompt| prompt["name"] == "translate" }
+
+    expect(translate_prompt["translated_name"]).to eq(
+      I18n.t("discourse_ai.ai_helper.prompts.translate"),
+    )
+
+    I18n.with_locale("fr") do
+      serializer = CurrentUserSerializer.new(french_user, scope: Guardian.new(french_user))
+      parsed = JSON.parse(serializer.to_json)
+
+      translate_prompt =
+        parsed["current_user"]["ai_helper_prompts"].find { |prompt| prompt["name"] == "translate" }
+
+      expect(translate_prompt["translated_name"]).to eq(
+        I18n.t("discourse_ai.ai_helper.prompts.translate", locale: "fr"),
+      )
+    end
+  end
+end