discourse-ai/lib/modules/embeddings/semantic_search.rb

100 lines
3.1 KiB
Ruby

# frozen_string_literal: true
module DiscourseAi
module Embeddings
class SemanticSearch
def self.clear_cache_for(query)
digest = OpenSSL::Digest::SHA1.hexdigest(query)
hyde_key =
"semantic-search-#{digest}-#{SiteSetting.ai_embeddings_semantic_search_hyde_model}"
Discourse.cache.delete(hyde_key)
Discourse.cache.delete("#{hyde_key}-#{SiteSetting.ai_embeddings_model}")
end
def initialize(guardian)
@guardian = guardian
end
def cached_query?(query)
digest = OpenSSL::Digest::SHA1.hexdigest(query)
embedding_key =
build_embedding_key(
digest,
SiteSetting.ai_embeddings_semantic_search_hyde_model,
SiteSetting.ai_embeddings_model,
)
Discourse.cache.read(embedding_key).present?
end
def search_for_topics(query, page = 1)
max_results_per_page = 100
limit = [Search.per_filter, max_results_per_page].min + 1
offset = (page - 1) * limit
search = Search.new(query, { guardian: guardian })
search_term = search.term
strategy = DiscourseAi::Embeddings::Strategies::Truncation.new
vector_rep =
DiscourseAi::Embeddings::VectorRepresentations::Base.current_representation(strategy)
digest = OpenSSL::Digest::SHA1.hexdigest(search_term)
hyde_key = build_hyde_key(digest, SiteSetting.ai_embeddings_semantic_search_hyde_model)
embedding_key =
build_embedding_key(
digest,
SiteSetting.ai_embeddings_semantic_search_hyde_model,
SiteSetting.ai_embeddings_model,
)
hypothetical_post =
Discourse
.cache
.fetch(hyde_key, expires_in: 1.week) do
hyde_generator = DiscourseAi::Embeddings::HydeGenerators::Base.current_hyde_model.new
hyde_generator.hypothetical_post_from(search_term)
end
hypothetical_post_embedding =
Discourse
.cache
.fetch(embedding_key, expires_in: 1.week) { vector_rep.vector_from(hypothetical_post) }
candidate_topic_ids =
vector_rep.asymmetric_topics_similarity_search(
hypothetical_post_embedding,
limit: limit,
offset: offset,
)
semantic_results =
::Post
.where(post_type: ::Topic.visible_post_types(guardian.user))
.public_posts
.where("topics.visible")
.where(topic_id: candidate_topic_ids, post_number: 1)
.order("array_position(ARRAY#{candidate_topic_ids}, topic_id)")
query_filter_results = search.apply_filters(semantic_results)
guardian.filter_allowed_categories(query_filter_results)
end
private
attr_reader :guardian
def build_hyde_key(digest, hyde_model)
"semantic-search-#{digest}-#{hyde_model}"
end
def build_embedding_key(digest, hyde_model, embedding_model)
"#{build_hyde_key(digest, hyde_model)}-#{embedding_model}"
end
end
end
end