Add Meilisearch indexer (#444)

internal/index/meilisearch.go

@@ -0,0 +1,146 @@
+package index
+
+import (
+	"errors"
+	"fmt"
+	"github.com/meilisearch/meilisearch-go"
+	"github.com/rs/zerolog/log"
+	"strconv"
+	"strings"
+)
+
+type MeiliIndexer struct {
+	client    meilisearch.ServiceManager
+	index     meilisearch.IndexManager
+	indexName string
+	host      string
+	apikey    string
+}
+
+func NewMeiliIndexer(host, apikey, indexName string) *MeiliIndexer {
+	return &MeiliIndexer{
+		host:      host,
+		apikey:    apikey,
+		indexName: indexName,
+	}
+}
+
+func (i *MeiliIndexer) Init() {
+	go func() {
+		meiliIndex, err := i.open()
+		if err != nil {
+			log.Error().Err(err).Msg("Failed to open Meilisearch index")
+			i.Close()
+		}
+		i.index = meiliIndex
+		log.Info().Msg("Meilisearch indexer initialized")
+	}()
+}
+
+func (i *MeiliIndexer) open() (meilisearch.IndexManager, error) {
+	client := meilisearch.New(i.host, meilisearch.WithAPIKey(i.apikey))
+	indexResult, err := client.GetIndex(i.indexName)
+	if err != nil {
+		return nil, err
+	}
+
+	if indexResult != nil {
+		return indexResult.IndexManager, nil
+	}
+	_, err = client.CreateIndex(&meilisearch.IndexConfig{
+		Uid:        i.indexName,
+		PrimaryKey: "GistID",
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	_, _ = client.Index(i.indexName).UpdateSettings(&meilisearch.Settings{
+		FilterableAttributes: []string{"GistID", "UserID", "Visibility", "Username", "Title", "Filenames", "Extensions", "Languages", "Topics"},
+		DisplayedAttributes:  []string{"GistID"},
+		SearchableAttributes: []string{"Content", "Username", "Title", "Filenames", "Extensions", "Languages", "Topics"},
+		RankingRules:         []string{"words"},
+	})
+
+	return client.Index(i.indexName), nil
+}
+
+func (i *MeiliIndexer) Close() {
+	if i.client != nil {
+		i.client.Close()
+		log.Info().Msg("Meilisearch indexer closed")
+	}
+	i.client = nil
+}
+
+func (i *MeiliIndexer) Add(gist *Gist) error {
+	if gist == nil {
+		return errors.New("failed to add nil gist to index")
+	}
+	_, err := (*atomicIndexer.Load()).(*MeiliIndexer).index.AddDocuments(gist, "GistID")
+	return err
+}
+
+func (i *MeiliIndexer) Remove(gistID uint) error {
+	_, err := (*atomicIndexer.Load()).(*MeiliIndexer).index.DeleteDocument(strconv.Itoa(int(gistID)))
+	return err
+}
+
+func (i *MeiliIndexer) Search(queryStr string, queryMetadata SearchGistMetadata, userId uint, page int) ([]uint, uint64, map[string]int, error) {
+	searchRequest := &meilisearch.SearchRequest{
+		Offset:               int64((page - 1) * 10),
+		Limit:                11,
+		AttributesToRetrieve: []string{"GistID", "Languages"},
+		Facets:               []string{"Languages"},
+		AttributesToSearchOn: []string{"Content"},
+	}
+
+	var filters []string
+	filters = append(filters, fmt.Sprintf("(Visibility = 0 OR UserID = %d)", userId))
+
+	addFilter := func(field, value string) {
+		if value != "" && value != "." {
+			filters = append(filters, fmt.Sprintf("%s = \"%s\"", field, escapeFilterValue(value)))
+		}
+	}
+	addFilter("Username", queryMetadata.Username)
+	addFilter("Title", queryMetadata.Title)
+	addFilter("Filenames", queryMetadata.Filename)
+	addFilter("Extensions", queryMetadata.Extension)
+	addFilter("Languages", queryMetadata.Language)
+	addFilter("Topics", queryMetadata.Topic)
+
+	if len(filters) > 0 {
+		searchRequest.Filter = strings.Join(filters, " AND ")
+	}
+
+	response, err := (*atomicIndexer.Load()).(*MeiliIndexer).index.Search(queryStr, searchRequest)
+	if err != nil {
+		log.Error().Err(err).Msg("Failed to search Meilisearch index")
+		return nil, 0, nil, err
+	}
+
+	gistIds := make([]uint, 0, len(response.Hits))
+	for _, hit := range response.Hits {
+		if gistID, ok := hit.(map[string]interface{})["GistID"].(float64); ok {
+			gistIds = append(gistIds, uint(gistID))
+		}
+	}
+
+	languageCounts := make(map[string]int)
+	if facets, ok := response.FacetDistribution.(map[string]interface{})["Languages"]; ok {
+		for language, count := range facets.(map[string]interface{}) {
+			if countValue, ok := count.(float64); ok {
+				languageCounts[language] = int(countValue)
+			}
+		}
+	}
+
+	return gistIds, uint64(response.EstimatedTotalHits), languageCounts, nil
+}
+
+func escapeFilterValue(value string) string {
+	escaped := strings.ReplaceAll(value, "\\", "\\\\")
+	escaped = strings.ReplaceAll(escaped, "\"", "\\\"")
+	return escaped
+}