FEATURE: Discord Bot integration (#831)

This adds support for the a Discord bot that can search in a Discourse instance when invoked via slash commands in Discord Guild channel.

Author: xfalcox

.gitignore

@@ -1,3 +1,4 @@
 node_modules
 /gems
 /auto_generated
+.env

app/controllers/discourse_ai/discord/bot_controller.rb

@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+module DiscourseAi
+  module Discord
+    class BotController < ::ApplicationController
+      requires_plugin ::DiscourseAi::PLUGIN_NAME
+
+      skip_before_action :verify_authenticity_token
+
+      def interactions
+        # Request signature verification
+        begin
+          verify_request!
+        rescue Ed25519::VerifyError
+          return head :unauthorized
+        end
+
+        body = request.body.read
+        interaction = JSON.parse(body, object_class: OpenStruct)
+
+        if interaction.type == 1
+          # Respond to Discord PING request
+          render json: { type: 1 }
+        else
+          if !SiteSetting.ai_discord_allowed_guilds_map.include?(interaction.guild_id)
+            return head :forbidden
+          end
+
+          response = { type: 5, data: { content: "Searching..." } }
+          hijack { render json: response }
+
+          # Respond to Discord command
+          Jobs.enqueue(:stream_discord_reply, interaction: body)
+        end
+      end
+
+      private
+
+      def verify_request!
+        signature = request.headers["X-Signature-Ed25519"]
+        timestamp = request.headers["X-Signature-Timestamp"]
+        verify_key.verify([signature].pack("H*"), "#{timestamp}#{request.raw_post}")
+      end
+
+      def verify_key
+        Ed25519::VerifyKey.new([SiteSetting.ai_discord_app_public_key].pack("H*")).freeze
+      end
+    end
+  end
+end

app/jobs/regular/stream_discord_reply.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module Jobs
+  class StreamDiscordReply < ::Jobs::Base
+    sidekiq_options retry: false
+
+    def execute(args)
+      interaction = args[:interaction]
+
+      if SiteSetting.ai_discord_search_mode == "persona"
+        DiscourseAi::Discord::Bot::PersonaReplier.new(interaction).handle_interaction!
+      else
+        DiscourseAi::Discord::Bot::Search.new(interaction).handle_interaction!
+      end
+    end
+  end
+end

config/routes.rb

@@ -15,6 +15,10 @@
     get "quick-search" => "embeddings#quick_search"
   end
 
+  scope module: :discord, path: "/discord", defaults: { format: :json } do
+    post "interactions" => "bot#interactions"
+  end
+
   scope module: :ai_bot, path: "/ai-bot", defaults: { format: :json } do
     get "bot-username" => "bot#show_bot_username"
     get "post/:post_id/show-debug-info" => "bot#show_debug_info"

config/settings.yml

@@ -431,3 +431,24 @@ discourse_ai:
     hidden: true
     type: list
     list_type: compact
+
+  ai_discord_app_id:
+    default: ""
+    client: false
+  ai_discord_app_public_key:
+    default: ""
+    client: false
+  ai_discord_search_mode:
+    default: "search"
+    type: enum
+    choices:
+      - search
+      - persona
+  ai_discord_search_persona:
+    default: ""
+    type: enum
+    enum: "DiscourseAi::Configuration::PersonaEnumerator"
+  ai_discord_allowed_guilds:
+    type: list
+    list_type: compact
+    default: ""

lib/configuration/persona_enumerator.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+require "enum_site_setting"
+
+module DiscourseAi
+  module Configuration
+    class PersonaEnumerator < ::EnumSiteSetting
+      def self.valid_value?(val)
+        true
+      end
+
+      def self.values
+        AiPersona.all_personas.map { |persona| { name: persona.name, value: persona.id } }
+      end
+    end
+  end
+end

lib/discord/bot/base.rb

@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+module DiscourseAi
+  module Discord::Bot
+    class Base
+      def initialize(body)
+        @interaction = JSON.parse(body, object_class: OpenStruct)
+        @query = @interaction.data.options.first.value
+        @token = @interaction.token
+      end
+
+      def handle_interaction!
+        raise NotImplementedError
+      end
+
+      def create_reply(reply)
+        api_endpoint = "https://discord.com/api/webhooks/#{SiteSetting.ai_discord_app_id}/#{@token}"
+        conn = Faraday.new { |f| f.adapter FinalDestination::FaradayAdapter }
+        response =
+          conn.post(
+            api_endpoint,
+            { content: reply }.to_json,
+            { "Content-Type" => "application/json" },
+          )
+        @reply_response = JSON.parse(response.body, symbolize_names: true)
+      end
+
+      def update_reply(reply)
+        api_endpoint =
+          "https://discord.com/api/webhooks/#{SiteSetting.ai_discord_app_id}/#{@token}/messages/@original"
+        conn = Faraday.new { |f| f.adapter FinalDestination::FaradayAdapter }
+        response =
+          conn.patch(
+            api_endpoint,
+            { content: reply }.to_json,
+            { "Content-Type" => "application/json" },
+          )
+        @last_update_response = JSON.parse(response.body, symbolize_names: true)
+      end
+    end
+  end
+end

lib/discord/bot/persona_replier.rb

@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+module DiscourseAi
+  module Discord::Bot
+    class PersonaReplier < Base
+      def initialize(body)
+        @persona =
+          AiPersona
+            .all_personas
+            .find { |persona| persona.id == SiteSetting.ai_discord_search_persona.to_i }
+            .new
+        @bot = DiscourseAi::AiBot::Bot.as(Discourse.system_user, persona: @persona, model: nil)
+        super(body)
+      end
+
+      def handle_interaction!
+        last_update_sent_at = Time.now - 1
+        reply = +""
+        full_reply =
+          @bot.reply(
+            { conversation_context: [{ type: :user, content: @query }], skip_tool_details: true },
+          ) do |partial, _cancel, _something|
+            reply << partial
+            next if reply.blank?
+
+            if @reply_response.nil?
+              create_reply(wrap_links(reply.dup))
+            elsif @last_update_response.nil?
+              update_reply(wrap_links(reply.dup))
+            elsif Time.now - last_update_sent_at > 1
+              update_reply(wrap_links(reply.dup))
+              last_update_sent_at = Time.now
+            end
+          end
+
+        discord_reply = wrap_links(full_reply.last.first)
+
+        if @reply_response.nil?
+          create_reply(discord_reply)
+        else
+          update_reply(discord_reply)
+        end
+      end
+
+      def wrap_links(text)
+        text.gsub(%r{(?<url>https?://[^\s]+)}, "<\\k<url>>")
+      end
+    end
+  end
+end

lib/discord/bot/search.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+module DiscourseAi
+  module Discord::Bot
+    class Search < Base
+      def initialize(body)
+        @search = DiscourseAi::AiBot::Tools::Search
+        super(body)
+      end
+
+      def handle_interaction!
+        results =
+          @search.new(
+            { search_query: @query },
+            persona_options: {
+              "max_results" => 10,
+            },
+            bot_user: nil,
+            llm: nil,
+          ).invoke(&Proc.new {})
+
+        formatted_results = results[:rows].map.with_index { |result, index| <<~RESULT }.join("\n")
+          #{index + 1}. [#{result[0]}](<#{Discourse.base_url}#{result[1]}>)
+          RESULT
+
+        reply = <<~REPLY
+          Here are the top search results for your query:
+
+          #{formatted_results}
+        REPLY
+
+        create_reply(reply)
+      end
+    end
+  end
+end

plugin.rb

@@ -10,6 +10,7 @@
 
 gem "tokenizers", "0.4.4"
 gem "tiktoken_ruby", "0.0.9"
+gem "ed25519", "1.2.4" #TODO remove this as existing ssl gem should handle this
 
 enabled_site_setting :discourse_ai_enabled