Search Index Build

providers/search/searchprovider.go

@@ -0,0 +1,129 @@
+package searchprovider
+
+import (
+	"errors"
+	"path/filepath"
+	"sync"
+
+	"github.com/Theodor-Springmann-Stiftung/kgpz_web/xmlmodels"
+	"github.com/blevesearch/bleve/v2"
+	"github.com/blevesearch/bleve/v2/analysis/analyzer/custom"
+	"github.com/blevesearch/bleve/v2/analysis/char/html"
+	"github.com/blevesearch/bleve/v2/analysis/char/regexp"
+	"github.com/blevesearch/bleve/v2/analysis/token/lowercase"
+	"github.com/blevesearch/bleve/v2/analysis/token/ngram"
+	"github.com/blevesearch/bleve/v2/analysis/token/unicodenorm"
+	"github.com/blevesearch/bleve/v2/analysis/tokenizer/unicode"
+	"github.com/blevesearch/bleve/v2/mapping"
+)
+
+var NoKeyError = errors.New("Missing ID key.")
+var NoLibError = errors.New("Missing library.")
+
+type ISearchable interface {
+	Keys() []string
+	Readable(lib *xmlmodels.Library) map[string]interface{}
+	Type() string
+}
+
+type SearchProvider struct {
+	indeces  sync.Map
+	basepath string
+}
+
+func NewSearchProvider(basepath string) (*SearchProvider, error) {
+	sp := &SearchProvider{basepath: basepath}
+	return sp, nil
+}
+
+func (sp *SearchProvider) Index(item ISearchable, lib *xmlmodels.Library) error {
+	keys := item.Keys()
+	if len(keys) == 0 {
+		return NoKeyError
+	}
+	if lib == nil {
+		return NoLibError
+	}
+
+	i, err := sp.FindCreateIndex(item.Type())
+	if err != nil {
+		return err
+	}
+
+	return i.Index(keys[0], item.Readable(lib))
+}
+
+func (sp *SearchProvider) FindCreateIndex(typ string) (bleve.Index, error) {
+	index, ok := sp.indeces.Load(typ)
+	if ok {
+		i := index.(bleve.Index)
+		return i, nil
+	}
+
+	fp := filepath.Join(sp.basepath, typ+".bleve")
+	ind, err := bleve.Open(fp)
+	if err == bleve.ErrorIndexPathDoesNotExist {
+		mapping, err := default_mapping()
+		if err != nil {
+			return nil, err
+		}
+		ind, err = bleve.New(filepath.Join(fp), mapping)
+		if err != nil {
+			return nil, err
+		}
+	}
+	sp.indeces.Store(typ, ind)
+
+	return ind, nil
+}
+
+func default_mapping() (*mapping.IndexMappingImpl, error) {
+	indexMapping := bleve.NewIndexMapping()
+
+	customunicodeFilter := map[string]interface{}{
+		"type": unicodenorm.Name,
+		"form": unicodenorm.NFKD,
+	}
+
+	customCharFilterConfig := map[string]interface{}{
+		"type":    regexp.Name,
+		"regexp":  `[[:punct:]]+`, // Removes all punctuation characters
+		"replace": "",
+	}
+
+	customNgramFilterConfig := map[string]interface{}{
+		"type": ngram.Name,
+		"min":  1,  // minimum n-gram size
+		"max":  20, // maximum n-gram size
+	}
+
+	customNgramAnalyzer := map[string]interface{}{
+		"type":          custom.Name,
+		"tokenizer":     unicode.Name,
+		"char_filters":  []string{"removePunctuation", html.Name},
+		"token_filters": []string{lowercase.Name, "customNgramFilter", "customUnicodeCharFilter"},
+	}
+
+	err := indexMapping.AddCustomTokenFilter("customNgramFilter", customNgramFilterConfig)
+	if err != nil {
+		return nil, err
+	}
+
+	err = indexMapping.AddCustomCharFilter("removePunctuation", customCharFilterConfig)
+	if err != nil {
+		return nil, err
+	}
+
+	err = indexMapping.AddCustomTokenFilter("customUnicodeCharFilter", customunicodeFilter)
+	if err != nil {
+		return nil, err
+	}
+
+	err = indexMapping.AddCustomAnalyzer("customNgramAnalyzer", customNgramAnalyzer)
+	if err != nil {
+		return nil, err
+	}
+
+	indexMapping.DefaultAnalyzer = "customNgramAnalyzer"
+	return indexMapping, nil
+}