[#432] Add get-object-attributes

Signed-off-by: Angira Kekteeva <kira@nspcc.ru>

api/handler/attributes.go

@@ -0,0 +1,233 @@
+package handler
+
+import (
+	"net/http"
+	"strconv"
+	"strings"
+
+	"github.com/nspcc-dev/neofs-s3-gw/api"
+	"github.com/nspcc-dev/neofs-s3-gw/api/data"
+	"github.com/nspcc-dev/neofs-s3-gw/api/errors"
+	"github.com/nspcc-dev/neofs-s3-gw/api/layer"
+)
+
+type (
+	GetObjectAttributesResponse struct {
+		ETag         string       `xml:"ETag,omitempty"`
+		ObjectSize   int64        `xml:"ObjectSize,omitempty"`
+		StorageClass string       `xml:"StorageClass,omitempty"`
+		ObjectParts  *ObjectParts `xml:"ObjectParts,omitempty"`
+	}
+
+	ObjectParts struct {
+		IsTruncated          bool   `xml:"IsTruncated,omitempty"`
+		MaxParts             int    `xml:"MaxParts,omitempty"`
+		NextPartNumberMarker int    `xml:"NextPartNumberMarker,omitempty"`
+		PartNumberMarker     int    `xml:"PartNumberMarker,omitempty"`
+		Parts                []Part `xml:"Part,omitempty"`
+		PartsCount           int    `xml:"PartsCount,omitempty"`
+	}
+
+	Part struct {
+		PartNumber int `xml:"PartNumber,omitempty"`
+		Size       int `xml:"Size,omitempty"`
+	}
+
+	GetObjectAttributesArgs struct {
+		MaxParts         int
+		PartNumberMarker int
+		Attributes       []string
+		VersionID        string
+	}
+)
+
+const (
+	partNumberMarkerDefault = -1
+
+	eTag         = "ETag"
+	checksum     = "Checksum"
+	objectParts  = "ObjectParts"
+	storageClass = "StorageClass"
+	objectSize   = "ObjectSize"
+)
+
+var validAttributes = map[string]struct{}{
+	eTag:         {},
+	checksum:     {},
+	objectParts:  {},
+	storageClass: {},
+	objectSize:   {},
+}
+
+func (h *handler) GetObjectAttributesHandler(w http.ResponseWriter, r *http.Request) {
+	var (
+		err  error
+		info *data.ObjectInfo
+
+		reqInfo = api.GetReqInfo(r.Context())
+	)
+
+	params, err := parseGetObjectAttributeArgs(r)
+	if err != nil {
+		h.logAndSendError(w, "invalid request", reqInfo, err)
+		return
+	}
+
+	bktInfo, err := h.getBucketAndCheckOwner(r, reqInfo.BucketName)
+	if err != nil {
+		h.logAndSendError(w, "could not get bucket info", reqInfo, err)
+		return
+	}
+
+	p := &layer.HeadObjectParams{
+		BktInfo:   bktInfo,
+		Object:    reqInfo.ObjectName,
+		VersionID: params.VersionID,
+	}
+
+	if info, err = h.obj.GetObjectInfo(r.Context(), p); err != nil {
+		h.logAndSendError(w, "could not fetch object info", reqInfo, err)
+		return
+	}
+
+	response, err := encodeToObjectAttributesResponse(info, params)
+	if err != nil {
+		h.logAndSendError(w, "couldn't encode object info to response", reqInfo, err)
+		return
+	}
+
+	writeAttributesHeaders(w.Header(), info, params)
+	if err = api.EncodeToResponse(w, response); err != nil {
+		h.logAndSendError(w, "something went wrong", reqInfo, err)
+	}
+}
+
+func writeAttributesHeaders(h http.Header, info *data.ObjectInfo, params *GetObjectAttributesArgs) {
+	h.Set(api.LastModified, info.Created.UTC().Format(http.TimeFormat))
+	if len(params.VersionID) != 0 {
+		h.Set(api.AmzVersionID, info.Version())
+	}
+
+	if _, ok := info.Headers[layer.VersionsDeleteMarkAttr]; ok {
+		h.Set(api.AmzDeleteMarker, strconv.FormatBool(true))
+	}
+
+	// x-amz-request-charged
+}
+
+func parseGetObjectAttributeArgs(r *http.Request) (*GetObjectAttributesArgs, error) {
+	var (
+		err error
+
+		res           = &GetObjectAttributesArgs{}
+		attributesVal = r.Header.Get("X-Amz-Object-Attributes")
+		maxPartsVal   = r.Header.Get("X-Amz-Max-Parts")
+		markerVal     = r.Header.Get("X-Amz-Part-Number-Marker")
+		queryValues   = r.URL.Query()
+	)
+
+	if attributesVal == "" {
+		return nil, errors.GetAPIError(errors.ErrInvalidAttributeName)
+	}
+
+	attributes := strings.Split(attributesVal, ",")
+	for _, a := range attributes {
+		if _, ok := validAttributes[a]; !ok {
+			return nil, errors.GetAPIError(errors.ErrInvalidAttributeName)
+		}
+		res.Attributes = append(res.Attributes, a)
+	}
+
+	if maxPartsVal == "" {
+		res.MaxParts = layer.MaxSizePartsList
+	} else if res.MaxParts, err = strconv.Atoi(maxPartsVal); err != nil || res.MaxParts < 0 {
+		return nil, errors.GetAPIError(errors.ErrInvalidMaxKeys)
+	}
+
+	if markerVal == "" {
+		res.PartNumberMarker = partNumberMarkerDefault
+	} else if res.PartNumberMarker, err = strconv.Atoi(markerVal); err != nil || res.PartNumberMarker < 0 {
+		return nil, errors.GetAPIError(errors.ErrInvalidPartNumberMarker)
+	}
+
+	res.VersionID = queryValues.Get(api.QueryVersionID)
+
+	return res, nil
+}
+
+func encodeToObjectAttributesResponse(info *data.ObjectInfo, p *GetObjectAttributesArgs) (*GetObjectAttributesResponse, error) {
+	resp := &GetObjectAttributesResponse{}
+
+	for _, attr := range p.Attributes {
+		switch attr {
+		case eTag:
+			resp.ETag = info.HashSum
+		case storageClass:
+			resp.StorageClass = "STANDARD"
+		case objectSize:
+			resp.ObjectSize = info.Size
+		case objectParts:
+			parts, err := formUploadAttributes(info, p.MaxParts, p.PartNumberMarker)
+			if err != nil {
+				return nil, err
+			}
+			if parts != nil {
+				resp.ObjectParts = parts
+			}
+		}
+	}
+
+	return resp, nil
+}
+
+func formUploadAttributes(info *data.ObjectInfo, maxParts, marker int) (*ObjectParts, error) {
+	res := ObjectParts{}
+
+	if _, ok := info.Headers[layer.UploadIDAttributeName]; !ok {
+		return nil, nil
+	}
+
+	parts := make([]Part, 0)
+	val, ok := info.Headers[layer.UploadCompletedParts]
+	if ok {
+		pairs := strings.Split(val, ",")
+		for _, p := range pairs {
+			// nums[0] -- part number, nums[1] -- part size
+			nums := strings.Split(p, "=")
+			if len(nums) != 2 {
+				return nil, nil
+			}
+			num, err := strconv.Atoi(nums[0])
+			if err != nil {
+				return nil, err
+			}
+			size, err := strconv.Atoi(nums[1])
+			if err != nil {
+				return nil, err
+			}
+			parts = append(parts, Part{PartNumber: num, Size: size})
+		}
+	}
+
+	res.PartsCount = len(parts)
+
+	if marker != partNumberMarkerDefault {
+		res.PartNumberMarker = marker
+		for i, n := range parts {
+			if n.PartNumber == marker {
+				parts = parts[i:]
+				break
+			}
+		}
+	}
+	res.MaxParts = maxParts
+	if len(parts) > maxParts {
+		res.IsTruncated = true
+		res.NextPartNumberMarker = parts[maxParts].PartNumber
+		parts = parts[:maxParts]
+	}
+
+	res.Parts = parts
+
+	return &res, nil
+}