chronicle_bot: An ambitious chat bot for Matrix

lib/chronicle_bot.rb

@@ -0,0 +1,130 @@
+# frozen_string_literal: true
+
+require 'faraday'
+require 'json'
+require 'matrix_sdk'
+
+# Chronicle Bot
+module Chronicle
+  # Require any addons
+  Dir[File.join(__dir__, 'addons', '*.rb')].each do |file|
+    require file
+  end
+
+  # A filter to simplify syncs
+  BOT_FILTER = {
+    presence: { types: [] },
+    account_data: { types: [] },
+    room: {
+      ephemeral: { types: [] },
+      state: {
+        types: ['m.room.*'],
+        lazy_load_members: true
+      },
+      timeline: {
+        types: ['m.room.message']
+      },
+      account_data: { types: [] }
+    }
+  }.freeze
+
+  # Chronicle Bot for Matrix
+  module Matrix
+    @@default_allowed_commands = %w[ping]
+    @@room_allowed_commands = {}
+
+    # Update allowed commands
+    def add_allowed_commands(cmds, msgid='')
+      if msgid
+        @@room_allowed_commands[msgid].concat(cmds)
+      else
+        @@room_allowed_commands.each { |_,v| v.concat(cmds) }
+      end
+    end
+
+    # Establish or return allowed commands for a room
+    def allowed_commands(msgid)
+      @@room_allowed_commands[msgid] ||= @@default_allowed_commands
+    end
+
+    # Begin the beast
+    def self.start(args)
+      unless args.length >= 2
+        raise "Usage: #{$PROGRAM_NAME} [-d] homeserver_url access_token"
+      end
+
+      if args.first == '-d'
+        Thread.abort_on_exception = true
+        MatrixSdk.debug!
+        args.shift
+      end
+
+      bot = ChronicleBot.new args[0], args[1]
+      bot.run
+    end
+
+    # The bot
+    class ChronicleBot
+      include Matrix
+
+      def initialize(hs_url, access_token)
+        @hs_url = hs_url
+        @token = access_token
+      end
+
+      # Run Chronicle
+      def run
+        # Join all invited rooms
+        client.on_invite_event.add_handler { |ev| client.join_room(ev[:room_id]) }
+
+        # Run an empty sync to get to a `since` token without old data.
+        # Storing the `since` token is also valid for bot use-cases, but in the
+        # case of ping responses there's never any need to reply to old data.
+        empty_sync = deep_copy(BOT_FILTER)
+        empty_sync[:room].map { |_k, v| v[:types] = [] }
+        client.sync filter: empty_sync
+
+        # Read all message events
+        client.on_event.add_handler('m.room.message') { |ev| on_message(ev) }
+
+        loop do
+          begin
+            client.sync filter: BOT_FILTER
+          rescue MatrixSdk::MatrixError => e
+            puts e
+          end
+        end
+      end
+
+      def on_message(message)
+        return unless message.content[:msgtype] == 'm.text'
+
+        msgstr = message.content[:body]
+        msgid = message.room_id
+        cmds = allowed_commands(msgid).join('|')
+
+        return unless msgstr =~ /^!#{cmds}\s*/
+
+        msgstr.match(/^!(#{cmds})\s*/) do |m| 
+          send(
+            "handle_#{m.to_s[1..-1].strip}",
+            client,
+            message
+          )
+        end
+      end
+
+      def client
+        @client ||= MatrixSdk::Client.new(
+          @hs_url,
+          access_token: @token,
+          client_cache: :none
+        )
+      end
+
+      def deep_copy(hash)
+        Marshal.load(Marshal.dump(hash))
+      end
+    end
+  end
+end