[#76] Refactor HeadObject logic

Signed-off-by: Denis Kirillov <denis@nspcc.ru>

downloader/head.go

@@ -0,0 +1,88 @@
+package downloader
+
+import (
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/nspcc-dev/neofs-api-go/pkg/client"
+	"github.com/nspcc-dev/neofs-api-go/pkg/object"
+	"github.com/nspcc-dev/neofs-http-gw/tokens"
+	"github.com/valyala/fasthttp"
+	"go.uber.org/zap"
+)
+
+const sizeToDetectType = 512
+
+func (r request) headObject(clnt client.Object, objectAddress *object.Address) {
+	var start = time.Now()
+	if err := tokens.StoreBearerToken(r.RequestCtx); err != nil {
+		r.log.Error("could not fetch and store bearer token", zap.Error(err))
+		r.Error("could not fetch and store bearer token", fasthttp.StatusBadRequest)
+		return
+	}
+
+	options := new(client.ObjectHeaderParams).WithAddress(objectAddress)
+	bearerOpt := bearerOpts(r.RequestCtx)
+	obj, err := clnt.GetObjectHeader(r.RequestCtx, options, bearerOpt)
+	if err != nil {
+		r.handleNeoFSErr(err, start)
+		return
+	}
+
+	r.Response.Header.Set("Content-Length", strconv.FormatUint(obj.PayloadSize(), 10))
+	var contentType string
+	for _, attr := range obj.Attributes() {
+		key := attr.Key()
+		val := attr.Value()
+		if !isValidToken(key) || !isValidValue(val) {
+			continue
+		}
+		r.Response.Header.Set("X-Attribute-"+key, val)
+		switch key {
+		case object.AttributeTimestamp:
+			value, err := strconv.ParseInt(val, 10, 64)
+			if err != nil {
+				r.log.Info("couldn't parse creation date",
+					zap.String("key", key),
+					zap.String("val", val),
+					zap.Error(err))
+				continue
+			}
+			r.Response.Header.Set("Last-Modified", time.Unix(value, 0).UTC().Format(http.TimeFormat))
+		case object.AttributeContentType:
+			contentType = val
+		}
+	}
+	r.Response.Header.Set("x-object-id", obj.ID().String())
+	r.Response.Header.Set("x-owner-id", obj.OwnerID().String())
+	r.Response.Header.Set("x-container-id", obj.ContainerID().String())
+
+	if len(contentType) == 0 {
+		objRange := object.NewRange()
+		objRange.SetOffset(0)
+		if sizeToDetectType < obj.PayloadSize() {
+			objRange.SetLength(sizeToDetectType)
+		} else {
+			objRange.SetLength(obj.PayloadSize())
+		}
+		ops := new(client.RangeDataParams).WithAddress(objectAddress).WithRange(objRange)
+		data, err := clnt.ObjectPayloadRangeData(r.RequestCtx, ops, bearerOpt)
+		if err != nil {
+			r.handleNeoFSErr(err, start)
+			return
+		}
+		contentType = http.DetectContentType(data)
+	}
+	r.SetContentType(contentType)
+}
+
+// HeadByAddress handles head requests using simple cid/oid format.
+func (d *Downloader) HeadByAddress(c *fasthttp.RequestCtx) {
+	d.byAddress(c, request.headObject)
+}
+
+// HeadByAttribute handles attribute-based head requests.
+func (d *Downloader) HeadByAttribute(c *fasthttp.RequestCtx) {
+	d.byAttribute(c, request.headObject)
+}