[#193] getsvc: Refactor get params creation

Resolve funlen linter for toPrm function.

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

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

@@ -32,7 +32,6 @@ import (
 
 var errWrongMessageSeq = errors.New("incorrect message sequence")
 
-// nolint: funlen, gocognit
 func (s *Service) toPrm(req *objectV2.GetRequest, stream objectSvc.GetObjectStream) (*getsvc.Prm, error) {
 	body := req.GetBody()
 
@@ -48,8 +47,6 @@ func (s *Service) toPrm(req *objectV2.GetRequest, stream objectSvc.GetObjectStre
 		return nil, fmt.Errorf("invalid object address: %w", err)
 	}
 
-	meta := req.GetMetaHeader()
-
 	commonPrm, err := util.CommonPrmFromV2(req)
 	if err != nil {
 		return nil, err
@@ -65,134 +62,17 @@ func (s *Service) toPrm(req *objectV2.GetRequest, stream objectSvc.GetObjectStre
 	p.SetObjectWriter(streamWrapper)
 
 	if !commonPrm.LocalOnly() {
-		var onceResign sync.Once
-
-		var onceHeaderSending sync.Once
-		var globalProgress int
+		forwarder := &getRequestForwarder{
+			OnceResign:        &sync.Once{},
+			OnceHeaderSending: &sync.Once{},
+			GlobalProgress:    0,
+			KeyStorage:        s.keyStorage,
+			Request:           req,
+			Stream:            streamWrapper,
+		}
 
 		p.SetRequestForwarder(groupAddressRequestForwarder(func(addr network.Address, c client.MultiAddressClient, pubkey []byte) (*object.Object, error) {
-			var err error
-
-			key, err := s.keyStorage.GetKey(nil)
-			if err != nil {
-				return nil, err
-			}
-
-			// 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: #1165 think how to set the other fields
-				metaHdr.SetOrigin(meta)
-				writeCurrentVersion(metaHdr)
-
-				req.SetMetaHeader(metaHdr)
-
-				err = signature.SignServiceMessage(key, req)
-			})
-
-			if err != nil {
-				return nil, err
-			}
-
-			// code below is copy-pasted from c.GetObject implementation,
-			// perhaps it is worth highlighting the utility function in frostfs-api-go
-
-			// open stream
-			var getStream *rpc.GetResponseReader
-			err = c.RawForAddress(addr, func(cli *rpcclient.Client) error {
-				getStream, err = rpc.GetObject(cli, req, rpcclient.WithContext(stream.Context()))
-				return err
-			})
-			if err != nil {
-				return nil, fmt.Errorf("stream opening failed: %w", err)
-			}
-
-			var (
-				headWas       bool
-				resp          = new(objectV2.GetResponse)
-				localProgress int
-			)
-
-			for {
-				// receive message from server stream
-				err := getStream.Read(resp)
-				if err != nil {
-					if errors.Is(err, io.EOF) {
-						if !headWas {
-							return nil, io.ErrUnexpectedEOF
-						}
-
-						break
-					}
-
-					internalclient.ReportError(c, err)
-					return nil, fmt.Errorf("reading the response failed: %w", err)
-				}
-
-				// verify response key
-				if err = internal.VerifyResponseKeyV2(pubkey, resp); err != nil {
-					return nil, err
-				}
-
-				// verify response structure
-				if err := signature.VerifyServiceMessage(resp); err != nil {
-					return nil, fmt.Errorf("response verification failed: %w", err)
-				}
-
-				if err = checkStatus(resp.GetMetaHeader().GetStatus()); err != nil {
-					return nil, err
-				}
-
-				switch v := resp.GetBody().GetObjectPart().(type) {
-				default:
-					return nil, fmt.Errorf("unexpected object part %T", v)
-				case *objectV2.GetObjectPartInit:
-					if headWas {
-						return nil, errWrongMessageSeq
-					}
-
-					headWas = true
-
-					obj := new(objectV2.Object)
-
-					obj.SetObjectID(v.GetObjectID())
-					obj.SetSignature(v.GetSignature())
-					obj.SetHeader(v.GetHeader())
-
-					onceHeaderSending.Do(func() {
-						err = streamWrapper.WriteHeader(stream.Context(), object.NewFromV2(obj))
-					})
-					if err != nil {
-						return nil, fmt.Errorf("could not write object header in Get forwarder: %w", err)
-					}
-				case *objectV2.GetObjectPartChunk:
-					if !headWas {
-						return nil, errWrongMessageSeq
-					}
-
-					origChunk := v.GetChunk()
-
-					chunk := chunkToSend(globalProgress, localProgress, origChunk)
-					if len(chunk) == 0 {
-						localProgress += len(origChunk)
-						continue
-					}
-
-					if err = streamWrapper.WriteChunk(stream.Context(), chunk); err != nil {
-						return nil, fmt.Errorf("could not write object chunk in Get forwarder: %w", err)
-					}
-
-					localProgress += len(origChunk)
-					globalProgress += len(chunk)
-				case *objectV2.SplitInfo:
-					si := object.NewSplitInfoFromV2(v)
-					return nil, object.NewSplitInfoError(si)
-				}
-			}
-
-			return nil, nil
+			return forwarder.forward(stream.Context(), addr, c, pubkey)
 		}))
 	}