add field

CONTRIBUTORS

@@ -211,3 +211,4 @@ zakthomas [@zakthomas](https://github.com/zakthomas)
 Zach [@snowzach](https://github.com/snowzach)
 zhangxin [@visaxin](https://github.com/visaxin)
 @林 [@zplzpl](https://github.com/zplzpl)
+@wth [@wth12138](https://github.com/wth12138)

search.go

@@ -363,6 +363,21 @@ func (s *SearchService) StoredFields(fields ...string) *SearchService {
 	return s
 }
 
+// Field adds a single field to load and return as
+// part of the post search request. If none are specified, the source of the
+// document will be returned.
+func (s *SearchService) Field(fieldName string) *SearchService {
+	s.searchSource = s.searchSource.Field(fieldName)
+	return s
+}
+
+// Fields	sets the fields to load and return as part of the search post request.
+// If none are specified, the source of the document will be returned.
+func (s *SearchService) Fields(fields ...string) *SearchService {
+	s.searchSource = s.searchSource.Fields(fields...)
+	return s
+}
+
 // TrackScores is applied when sorting and controls if scores will be
 // tracked as well. Defaults to false.
 func (s *SearchService) TrackScores(trackScores bool) *SearchService {

search_source.go

@@ -28,6 +28,7 @@ type SearchSource struct {
 	timeout                  string                 // timeout
 	terminateAfter           *int                   // terminate_after
 	storedFieldNames         []string               // stored_fields
+	fields                   []string               // fields
 	docvalueFields           DocvalueFields         // docvalue_fields
 	scriptFields             []*ScriptField         // script_fields
 	fetchSourceContext       *FetchSourceContext    // _source
@@ -297,6 +298,21 @@ func (s *SearchSource) StoredFields(storedFieldNames ...string) *SearchSource {
 	return s
 }
 
+// Field adds a single field to load and return as
+// part of the post search request. If none are specified, the source of the
+// document will be returned (need _source set false) .
+func (s *SearchSource) Field(FieldName string) *SearchSource {
+	s.storedFieldNames = append(s.fields, FieldName)
+	return s
+}
+
+// Fields	sets the fields to load and return as part of the search post request.
+// If none are specified, the source of the document will be returned (need _source set false).
+func (s *SearchSource) Fields(FieldNames ...string) *SearchSource {
+	s.fields = append(s.fields, FieldNames...)
+	return s
+}
+
 // DocvalueField adds a single field to load from the field data cache
 // and return as part of the search request.
 func (s *SearchSource) DocvalueField(fieldDataField string) *SearchSource {
@@ -440,6 +456,14 @@ func (s *SearchSource) Source() (interface{}, error) {
 			source["stored_fields"] = s.storedFieldNames
 		}
 	}
+	if s.fields != nil {
+		switch len(s.fields) {
+		case 1:
+			source["fields"] = s.fields[0]
+		default:
+			source["fields"] = s.fields
+		}
+	}
 	if len(s.docvalueFields) > 0 {
 		src, err := s.docvalueFields.Source()
 		if err != nil {

search_source_test.go

@@ -76,6 +76,24 @@ func TestSearchSourceStoredFields(t *testing.T) {
 	}
 }
 
+func TestSearchSourceFields(t *testing.T) {
+	matchAllQ := NewMatchAllQuery()
+	builder := NewSearchSource().Query(matchAllQ).Fields("message", "tags")
+	src, err := builder.Source()
+	if err != nil {
+		t.Fatal(err)
+	}
+	data, err := json.Marshal(src)
+	if err != nil {
+		t.Fatalf("marshaling to JSON failed: %v", err)
+	}
+	got := string(data)
+	expected := `{"fields":["message","tags"],"query":{"match_all":{}}}`
+	if got != expected {
+		t.Errorf("expected\n%s\n,got:\n%s", expected, got)
+	}
+}
+
 func TestSearchSourceFetchSourceDisabled(t *testing.T) {
 	matchAllQ := NewMatchAllQuery()
 	builder := NewSearchSource().Query(matchAllQ).FetchSource(false)