[#431] object/search: Re-sign original requests during forwarding

In previous implementation node's Object Search V2 service handler created a
new request for each RPC. Now original requests are re-signed according to
API specification. Logical handler abstracts from this version-dependent
logic through `RequestForwarder` callback.

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

pkg/services/object/search/prm.go

@@ -13,6 +13,8 @@ type Prm struct {
 	common *util.CommonPrm
 
 	client.SearchObjectParams
+
+	forwarder RequestForwarder
 }
 
 // IDListWriter is an interface of target component
@@ -21,6 +23,10 @@ type IDListWriter interface {
 	WriteIDs([]*objectSDK.ID) error
 }
 
+// RequestForwarder is a callback for forwarding of the
+// original Search requests.
+type RequestForwarder func(client.Client) ([]*objectSDK.ID, error)
+
 // SetCommonParameters sets common parameters of the operation.
 func (p *Prm) SetCommonParameters(common *util.CommonPrm) {
 	p.common = common
@@ -30,3 +36,9 @@ func (p *Prm) SetCommonParameters(common *util.CommonPrm) {
 func (p *Prm) SetWriter(w IDListWriter) {
 	p.writer = w
 }
+
+// SetRequestForwarder sets callback for forwarding
+// of the original request.
+func (p *Prm) SetRequestForwarder(f RequestForwarder) {
+	p.forwarder = f
+}

pkg/services/object/search/util.go

@@ -76,9 +76,7 @@ func (c *clientConstructorWrapper) get(addr string) (searchClient, error) {
 }
 
 func (c *clientWrapper) searchObjects(exec *execCtx) ([]*objectSDK.ID, error) {
-	return c.client.SearchObject(exec.context(),
-		exec.remotePrm(),
-		exec.callOptions()...)
+	return exec.prm.forwarder(c.client)
 }
 
 func (e *storageEngineWrapper) search(exec *execCtx) ([]*objectSDK.ID, error) {

pkg/services/object/search/v2/util.go

@@ -1,13 +1,22 @@
 package searchsvc
 
 import (
+	"io"
+	"sync"
+
+	"github.com/nspcc-dev/neofs-api-go/pkg/client"
 	"github.com/nspcc-dev/neofs-api-go/pkg/container"
 	objectSDK "github.com/nspcc-dev/neofs-api-go/pkg/object"
 	"github.com/nspcc-dev/neofs-api-go/pkg/token"
+	rpcclient "github.com/nspcc-dev/neofs-api-go/rpc/client"
 	objectV2 "github.com/nspcc-dev/neofs-api-go/v2/object"
+	"github.com/nspcc-dev/neofs-api-go/v2/rpc"
+	"github.com/nspcc-dev/neofs-api-go/v2/session"
+	"github.com/nspcc-dev/neofs-api-go/v2/signature"
 	objectSvc "github.com/nspcc-dev/neofs-node/pkg/services/object"
 	searchsvc "github.com/nspcc-dev/neofs-node/pkg/services/object/search"
 	"github.com/nspcc-dev/neofs-node/pkg/services/object/util"
+	"github.com/pkg/errors"
 )
 
 func (s *Service) toPrm(req *objectV2.SearchRequest, stream objectSvc.SearchStream) (*searchsvc.Prm, error) {
@@ -32,6 +41,67 @@ func (s *Service) toPrm(req *objectV2.SearchRequest, stream objectSvc.SearchStre
 		stream: stream,
 	})
 
+	if !commonPrm.LocalOnly() {
+		var onceResign sync.Once
+
+		p.SetRequestForwarder(func(c client.Client) ([]*objectSDK.ID, error) {
+			var err error
+
+			// once compose and resign forwarding request
+			onceResign.Do(func() {
+				// compose meta header of the local server
+				metaHdr := new(session.RequestMetaHeader)
+				metaHdr.SetTTL(meta.GetTTL() - 1)
+				// TODO: think how to set the other fields
+				metaHdr.SetOrigin(meta)
+
+				req.SetMetaHeader(metaHdr)
+
+				err = signature.SignServiceMessage(key, req)
+			})
+
+			if err != nil {
+				return nil, err
+			}
+
+			stream, err := rpc.SearchObjects(c.Raw(), req, rpcclient.WithContext(stream.Context()))
+			if err != nil {
+				return nil, err
+			}
+
+			// code below is copy-pasted from c.SearchObjects implementation,
+			// perhaps it is worth highlighting the utility function in neofs-api-go
+			var (
+				searchResult []*objectSDK.ID
+				resp         = new(objectV2.SearchResponse)
+			)
+
+			for {
+				// receive message from server stream
+				err := stream.Read(resp)
+				if err != nil {
+					if errors.Is(errors.Cause(err), io.EOF) {
+						break
+					}
+
+					return nil, errors.Wrap(err, "reading the response failed")
+				}
+
+				// verify response structure
+				if err := signature.VerifyServiceMessage(resp); err != nil {
+					return nil, errors.Wrapf(err, "could not verify %T", resp)
+				}
+
+				chunk := resp.GetBody().GetIDList()
+				for i := range chunk {
+					searchResult = append(searchResult, objectSDK.NewIDFromV2(chunk[i]))
+				}
+			}
+
+			return searchResult, nil
+		})
+	}
+
 	body := req.GetBody()
 	p.WithContainerID(container.NewIDFromV2(body.GetContainerID()))
 	p.WithSearchFilters(objectSDK.NewSearchFiltersFromV2(body.GetFilters()))