Inner hits support

CHANGELOG.md

@@ -5,6 +5,8 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 ## [Unreleased]
 ### Dependencies
 ### Added
+- Adds `InnerHits` field to `SearchResp` ([#672](https://github.com/opensearch-project/opensearch-go/pull/672))
+
 ### Changed
 ### Deprecated
 ### Removed

opensearchapi/api_search.go

@@ -63,17 +63,10 @@ func (r SearchReq) GetRequest() (*http.Request, error) {
 
 // SearchResp represents the returned struct of the /_search response
 type SearchResp struct {
-	Took    int            `json:"took"`
-	Timeout bool           `json:"timed_out"`
-	Shards  ResponseShards `json:"_shards"`
-	Hits    struct {
-		Total struct {
-			Value    int    `json:"value"`
-			Relation string `json:"relation"`
-		} `json:"total"`
-		MaxScore float32     `json:"max_score"`
-		Hits     []SearchHit `json:"hits"`
-	} `json:"hits"`
+	Took         int                  `json:"took"`
+	Timeout      bool                 `json:"timed_out"`
+	Shards       ResponseShards       `json:"_shards"`
+	Hits         SearchHits           `json:"hits"`
 	Errors       bool                 `json:"errors"`
 	Aggregations json.RawMessage      `json:"aggregations"`
 	ScrollID     *string              `json:"_scroll_id,omitempty"`
@@ -86,14 +79,27 @@ func (r SearchResp) Inspect() Inspect {
 	return Inspect{Response: r.response}
 }
 
+// SearchHits is a list of SearchHit with Total and MaxScore fields
+type SearchHits struct {
+	Total struct {
+		Value    int    `json:"value"`
+		Relation string `json:"relation"`
+	} `json:"total"`
+	MaxScore float32     `json:"max_score"`
+	Hits     []SearchHit `json:"hits"`
+}
+
 // SearchHit is a sub type of SearchResp containing information of the search hit with an unparsed Source field
 type SearchHit struct {
-	Index          string                  `json:"_index"`
-	ID             string                  `json:"_id"`
-	Routing        string                  `json:"_routing"`
-	Score          float32                 `json:"_score"`
-	Source         json.RawMessage         `json:"_source"`
-	Fields         json.RawMessage         `json:"fields"`
+	Index     string          `json:"_index"`
+	ID        string          `json:"_id"`
+	Routing   string          `json:"_routing"`
+	Score     float32         `json:"_score"`
+	Source    json.RawMessage `json:"_source"`
+	Fields    json.RawMessage `json:"fields"`
+	InnerHits map[string]struct {
+		Hits SearchHits `json:"hits"`
+	} `json:"inner_hits"`
 	Type           string                  `json:"_type"` // Deprecated field
 	Sort           []any                   `json:"sort"`
 	Explanation    *DocumentExplainDetails `json:"_explanation"`

opensearchapi/api_search_test.go

@@ -27,12 +27,28 @@ func TestSearch(t *testing.T) {
 
 	index := "test-index-search"
 
+	_, err = client.Indices.Create(
+		nil,
+		opensearchapi.IndicesCreateReq{
+			Index: index,
+			Body: strings.NewReader(`{
+				"mappings": {
+					"properties": {
+						"baz": {
+							"type": "nested"
+						}
+					}
+				}
+			}`),
+		},
+	)
+	require.Nil(t, err)
 	_, err = client.Index(
 		nil,
 		opensearchapi.IndexReq{
 			DocumentID: "foo",
 			Index:      index,
-			Body:       strings.NewReader(`{"foo": "bar"}`),
+			Body:       strings.NewReader(`{"foo": "bar", "baz": [{"foo": "test"}]}`),
 			Params:     opensearchapi.IndexParams{Refresh: "true", Routing: "foo"},
 		},
 	)
@@ -227,4 +243,31 @@ func TestSearch(t *testing.T) {
 		assert.NotEmpty(t, resp.Hits.Hits)
 		assert.Equal(t, []string{"test"}, resp.Hits.Hits[0].MatchedQueries)
 	})
+
+	t.Run("request with inner hits", func(t *testing.T) {
+		resp, err := client.Search(
+			nil,
+			&opensearchapi.SearchReq{
+				Indices: []string{index},
+				Body: strings.NewReader(`{
+					"query": {
+						"nested": {
+							"path": "baz",
+							"query": {
+								"match": {
+									"baz.foo": "test"
+								}
+							},
+							"inner_hits": {}
+						}
+					}
+				}`),
+			},
+		)
+		require.Nil(t, err)
+		assert.NotEmpty(t, resp.Hits.Hits)
+		assert.NotEmpty(t, resp.Hits.Hits[0].InnerHits)
+		assert.NotNil(t, resp.Hits.Hits[0].InnerHits["baz"])
+		assert.NotEmpty(t, resp.Hits.Hits[0].InnerHits["baz"].Hits.Hits)
+	})
 }