Add destroy_from_vectorsearch hook (#82)

* Add destroy_from_vectorsearch hook

* Tiny spec

* Fixes

* Update README.md

Author: andreibondarev

lib/langchainrb_overrides/vectorsearch/pgvector.rb

@@ -55,6 +55,16 @@ def update_texts(texts:, ids:)
       add_texts(texts: texts, ids: ids)
     end
 
+    # Remove vectors from the index
+    #
+    # @param ids [Array<String>] The ids of the vectors to remove
+    # @return [Boolean] true
+    def remove_texts(ids:)
+      # Since the record is being destroyed and the `embedding` is a column on the record,
+      # we don't need to do anything here.
+      true
+    end
+
     # Invoke a rake task that will create an initializer (`config/initializers/langchain.rb`) file
     # and db/migrations/* files
     def create_default_schema

lib/langchainrb_rails/active_record/hooks.rb

@@ -6,12 +6,14 @@ module ActiveRecord
     # * `vectorsearch` class method to set the vector search provider
     # * `similarity_search` class method to search for similar texts
     # * `upsert_to_vectorsearch` instance method to upsert the record to the vector search provider
+    # * `destroy_from_vectorsearch` instance method to remove the record from the vector search provider
     #
     # Usage:
     #     class Recipe < ActiveRecord::Base
     #       vectorsearch
     #
     #       after_save :upsert_to_vectorsearch
+    #       after_destroy :destroy_from_vectorsearch
     #
     #       # Overwriting how the model is serialized before it's indexed
     #       def as_vector
@@ -56,6 +58,17 @@ def upsert_to_vectorsearch
         end
       end
 
+      # Remove the record from the vector search provider
+      # This method should be called in an ActiveRecord `after_destroy` callback
+      #
+      # @return [Boolean] true
+      # @raise [Error] Removing from vector search DB failed
+      def destroy_from_vectorsearch
+        self.class.class_variable_get(:@@provider).remove_texts(
+          ids: [id]
+        )
+      end
+
       # Used to serialize the DB record to an indexable vector text
       # Overwrite this method in your model to customize
       #

spec/langchainrb_rails/active_record/hooks_spec.rb

@@ -7,6 +7,7 @@ class Dummy
 RSpec.describe LangchainrbRails::ActiveRecord::Hooks do
   it "responds to instance methods" do
     expect(::Dummy.new).to respond_to(:upsert_to_vectorsearch)
+    expect(::Dummy.new).to respond_to(:destroy_from_vectorsearch)
     expect(::Dummy.new).to respond_to(:as_vector)
   end