func (vs *VolumeServer) getNeedleHandler(w http.ResponseWriter, r *http.Request) {
	fid, err := storage.NewFileIdFromNid(r.FormValue("volume"), r.FormValue("nid"))
	if err != nil {
		glog.V(2).Infoln("parsing fid error:", err, r.URL.Path)
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	n, e := vs.store.ReadLocalNeedle(fid)
	if e != nil {
		e := fmt.Errorf("read needle (%v) error: %v", fid, err)
		glog.V(2).Infoln(e)
		writeJsonError(w, r, http.StatusNotFound, e)
		return
	}

	w.Header().Set("Seaweed-Flags", strconv.FormatInt(int64(n.Flags), 16))
	w.Header().Set("Seaweed-Checksum", strconv.FormatInt(int64(n.Checksum), 16))
	if n.HasLastModifiedDate() {
		w.Header().Set("Seaweed-LastModified", strconv.FormatUint(n.LastModified, 16))
	}
	if n.HasName() && n.NameSize > 0 {
		w.Header().Set("Seaweed-Name", string(n.Name))
	}
	if n.HasMime() && n.MimeSize > 0 {
		w.Header().Set("Seaweed-Mime", string(n.Mime))
	}
	w.Write(n.Data)
}
func (vs *VolumeServer) GetOrHeadHandler(w http.ResponseWriter, r *http.Request) {
	vid, nid, filename, ext, _ := parseURLPath(r.URL.Path)
	volumeId, err := storage.NewVolumeId(vid)
	if err != nil {
		glog.V(2).Infoln("parsing error:", err, r.URL.Path)
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	var (
		n *storage.Needle
	)

	fid, err := storage.NewFileIdFromNid(vid, nid)
	if err != nil {
		glog.V(2).Infoln("parsing fid error:", err, r.URL.Path)
		w.WriteHeader(http.StatusBadRequest)
		return
	}
	glog.V(4).Infoln("volume", volumeId, "reading", n)
	if vs.store.HasVolume(volumeId) {
		n, err = vs.store.ReadLocalNeedle(fid)
		glog.V(4).Infoln("read local needle", fid, "error", err)
		if err != nil {
			glog.V(0).Infoln("read local error:", err, r.URL.Path)
			w.WriteHeader(http.StatusNotFound)
			return
		}
	} else if vs.ReadRemoteNeedle {
		n, err = vs.store.ReadRemoteNeedle(fid, r.FormValue("collection"))
		glog.V(4).Infoln("read remote needle", fid, "error", err)
		if err != nil {
			glog.V(0).Infoln("read remote error:", err, ",url path:", r.URL.Path)
			w.WriteHeader(http.StatusNotFound)
			return
		}
	} else if vs.ReadRedirect {
		lookupResult, err := operation.Lookup(vs.GetMasterNode(), volumeId.String(), r.FormValue("collection"))
		glog.V(2).Infoln("volume", volumeId, "found on", lookupResult, "error", err)
		if err == nil && len(lookupResult.Locations) > 0 {
			u, _ := url.Parse(util.NormalizeUrl(lookupResult.Locations.PickForRead().PublicUrl))
			u.Path = r.URL.Path
			http.Redirect(w, r, u.String(), http.StatusMovedPermanently)
		} else {
			glog.V(2).Infoln("lookup error:", err, r.URL.Path)
			w.WriteHeader(http.StatusNotFound)
		}
		return
	} else {
		glog.V(2).Infoln("volume is not local:", err, r.URL.Path)
		w.WriteHeader(http.StatusNotFound)
		return
	}

	if n.LastModified != 0 {
		w.Header().Set("Last-Modified", time.Unix(int64(n.LastModified), 0).UTC().Format(http.TimeFormat))
		if r.Header.Get("If-Modified-Since") != "" {
			if t, parseError := time.Parse(http.TimeFormat, r.Header.Get("If-Modified-Since")); parseError == nil {
				if t.Unix() >= int64(n.LastModified) {
					w.WriteHeader(http.StatusNotModified)
					return
				}
			}
		}
	}
	etag := n.Etag()
	if inm := r.Header.Get("If-None-Match"); inm == etag {
		w.WriteHeader(http.StatusNotModified)
		return
	}
	w.Header().Set("Etag", etag)

	if vs.tryHandleChunkedFile(volumeId, n, filename, w, r) {
		return
	}

	if n.NameSize > 0 && filename == "" {
		filename = string(n.Name)
		if ext == "" {
			ext = path.Ext(filename)
		}
	}
	mtype := ""
	if n.MimeSize > 0 {
		mt := string(n.Mime)
		if !strings.HasPrefix(mt, "application/octet-stream") {
			mtype = mt
		}
	}
	needleData := n.Data
	if ext != ".gz" {
		if n.IsGzipped() {
			if strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
				w.Header().Set("Content-Encoding", "gzip")
			} else {
				if needleData, err = operation.UnGzipData(needleData); err != nil {
					glog.V(0).Infoln("ungzip error:", err, r.URL.Path)
				}
			}
		}
	}
	if ext == ".png" || ext == ".jpg" || ext == ".gif" {
		width, height := 0, 0
		if r.FormValue("width") != "" {
			width, _ = strconv.Atoi(r.FormValue("width"))
		}
		if r.FormValue("height") != "" {
			height, _ = strconv.Atoi(r.FormValue("height"))
		}
		if needleData, _, _, err = images.Resized(ext, needleData, width, height); err != nil {
			glog.V(0).Infoln("resize image error,", err, r.URL.Path)
		}
	}

	if err = writeResponseContent(filename, mtype, bytes.NewReader(needleData), w, r); err != nil {
		glog.V(2).Infoln("response write error:", err, r.URL.Path)
	}
}