update referrers api (#20068)

Update the referrers API according to the changeset in distribution spec 1.1, available at https://github.com/opencontainers/distribution-spec/pull/491/files.

Signed-off-by: wang yan <wangyan@vmware.com>

src/server/registry/referrers.go

@@ -63,20 +63,8 @@ func (r *referrersHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 		return
 	}
 
-	// Get the artifact by reference
-	art, err := r.artifactManager.GetByDigest(ctx, repository, reference)
-	if err != nil {
-		if errors.IsNotFoundErr(err) {
-			// If artifact not found, return empty json
-			newListReferrersOK().WithPayload(nil).WriteResponse(w)
-			return
-		}
-		lib_http.SendError(w, err)
-		return
-	}
-
 	// Query accessories with matching subject artifact digest
-	query := q.New(q.KeyWords{"SubjectArtifactDigest": art.Digest, "SubjectArtifactRepo": art.RepositoryName})
+	query := q.New(q.KeyWords{"SubjectArtifactDigest": reference, "SubjectArtifactRepo": repository})
 	total, err := r.accessoryManager.Count(ctx, query)
 	if err != nil {
 		lib_http.SendError(w, err)

src/server/registry/referrers_test.go

@@ -3,15 +3,13 @@ package registry
 import (
 	"context"
 	"encoding/json"
-	"fmt"
 	"net/http"
 	"net/http/httptest"
 	"testing"
 
 	beegocontext "github.com/beego/beego/v2/server/web/context"
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 
-	"github.com/goharbor/harbor/src/lib/errors"
 	accessorymodel "github.com/goharbor/harbor/src/pkg/accessory/model"
 	basemodel "github.com/goharbor/harbor/src/pkg/accessory/model/base"
 	"github.com/goharbor/harbor/src/pkg/artifact"
@@ -93,8 +91,10 @@ func TestReferrersHandlerEmpty(t *testing.T) {
 	artifactMock := &arttesting.Manager{}
 	accessoryMock := &accessorytesting.Manager{}
 
-	artifactMock.On("GetByDigest", mock.Anything, mock.Anything, mock.Anything).
-		Return(nil, errors.NotFoundError(nil))
+	accessoryMock.On("Count", mock.Anything, mock.Anything).
+		Return(int64(0), nil)
+	accessoryMock.On("List", mock.Anything, mock.Anything).
+		Return([]accessorymodel.Accessory{}, nil)
 
 	handler := &referrersHandler{
 		artifactManager:  artifactMock,
@@ -109,7 +109,6 @@ func TestReferrersHandlerEmpty(t *testing.T) {
 	}
 	index := &ocispec.Index{}
 	json.Unmarshal([]byte(rec.Body.String()), index)
-	fmt.Println(index)
 	if index.SchemaVersion != 0 && len(index.Manifests) != -0 {
 		t.Errorf("Expected empty response body, but got %s", rec.Body.String())
 	}