package handler import ( "fmt" "net/http" "strconv" "strings" "time" "github.com/nspcc-dev/neofs-s3-gw/api" "github.com/nspcc-dev/neofs-s3-gw/api/errors" "github.com/nspcc-dev/neofs-s3-gw/api/layer" ) type conditionalArgs struct { IfModifiedSince *time.Time IfUnmodifiedSince *time.Time IfMatch string IfNoneMatch string } type getObjectArgs struct { Conditional *conditionalArgs } func fetchRangeHeader(headers http.Header, fullSize uint64) (*layer.RangeParams, error) { const prefix = "bytes=" rangeHeader := headers.Get("Range") if len(rangeHeader) == 0 { return nil, nil } if fullSize == 0 { return nil, errors.GetAPIError(errors.ErrInvalidRange) } if !strings.HasPrefix(rangeHeader, prefix) { return nil, fmt.Errorf("unknown unit in range header") } arr := strings.Split(strings.TrimPrefix(rangeHeader, prefix), "-") if len(arr) != 2 || (len(arr[0]) == 0 && len(arr[1]) == 0) { return nil, fmt.Errorf("unknown byte-range-set") } var end, start uint64 var err0, err1 error base, bitSize := 10, 64 if len(arr[0]) == 0 { end, err1 = strconv.ParseUint(arr[1], base, bitSize) start = fullSize - end end = fullSize - 1 } else if len(arr[1]) == 0 { start, err0 = strconv.ParseUint(arr[0], base, bitSize) end = fullSize - 1 } else { start, err0 = strconv.ParseUint(arr[0], base, bitSize) end, err1 = strconv.ParseUint(arr[1], base, bitSize) if end > fullSize-1 { end = fullSize - 1 } } if err0 != nil || err1 != nil || start > end || start > fullSize { return nil, errors.GetAPIError(errors.ErrInvalidRange) } return &layer.RangeParams{Start: start, End: end}, nil } func writeHeaders(h http.Header, info *layer.ObjectInfo) { if len(info.ContentType) > 0 { h.Set(api.ContentType, info.ContentType) } h.Set(api.LastModified, info.Created.UTC().Format(http.TimeFormat)) h.Set(api.ContentLength, strconv.FormatInt(info.Size, 10)) h.Set(api.ETag, info.HashSum) h.Set(api.AmzVersionId, info.ID().String()) for key, val := range info.Headers { h[api.MetadataPrefix+key] = []string{val} } } func (h *handler) GetObjectHandler(w http.ResponseWriter, r *http.Request) { var ( err error inf *layer.ObjectInfo params *layer.RangeParams reqInfo = api.GetReqInfo(r.Context()) ) args, err := parseGetObjectArgs(r.Header) if err != nil { h.logAndSendError(w, "could not parse request params", reqInfo, err) return } if err = h.checkBucketOwner(r, reqInfo.BucketName); err != nil { h.logAndSendError(w, "expected owner doesn't match", reqInfo, err) return } p := &layer.HeadObjectParams{ Bucket: reqInfo.BucketName, Object: reqInfo.ObjectName, VersionID: reqInfo.URL.Query().Get("versionId"), } if inf, err = h.obj.GetObjectInfo(r.Context(), p); err != nil { h.logAndSendError(w, "could not find object", reqInfo, err) return } if err = checkPreconditions(inf, args.Conditional); err != nil { h.logAndSendError(w, "precondition failed", reqInfo, err) return } if params, err = fetchRangeHeader(r.Header, uint64(inf.Size)); err != nil { h.logAndSendError(w, "could not parse range header", reqInfo, err) return } writeHeaders(w.Header(), inf) if params != nil { writeRangeHeaders(w, params, inf.Size) } getParams := &layer.GetObjectParams{ ObjectInfo: inf, Writer: w, Range: params, VersionID: p.VersionID, } if err = h.obj.GetObject(r.Context(), getParams); err != nil { h.logAndSendError(w, "could not get object", reqInfo, err) } } func checkPreconditions(inf *layer.ObjectInfo, args *conditionalArgs) error { if len(args.IfMatch) > 0 && args.IfMatch != inf.HashSum { return errors.GetAPIError(errors.ErrPreconditionFailed) } if len(args.IfNoneMatch) > 0 && args.IfNoneMatch == inf.HashSum { return errors.GetAPIError(errors.ErrNotModified) } if args.IfModifiedSince != nil && inf.Created.Before(*args.IfModifiedSince) { return errors.GetAPIError(errors.ErrNotModified) } if args.IfUnmodifiedSince != nil && inf.Created.After(*args.IfUnmodifiedSince) { if len(args.IfMatch) == 0 { return errors.GetAPIError(errors.ErrPreconditionFailed) } } return nil } func parseGetObjectArgs(headers http.Header) (*getObjectArgs, error) { var err error args := &conditionalArgs{ IfMatch: headers.Get(api.IfMatch), IfNoneMatch: headers.Get(api.IfNoneMatch), } if args.IfModifiedSince, err = parseHTTPTime(headers.Get(api.IfModifiedSince)); err != nil { return nil, err } if args.IfUnmodifiedSince, err = parseHTTPTime(headers.Get(api.IfUnmodifiedSince)); err != nil { return nil, err } return &getObjectArgs{Conditional: args}, nil } func parseHTTPTime(data string) (*time.Time, error) { if len(data) == 0 { return nil, nil } result, err := time.Parse(http.TimeFormat, data) if err != nil { return nil, fmt.Errorf("couldn't parse http time %s: %w", data, err) } return &result, nil } func writeRangeHeaders(w http.ResponseWriter, params *layer.RangeParams, size int64) { w.Header().Set(api.AcceptRanges, "bytes") w.Header().Set(api.ContentRange, fmt.Sprintf("bytes %d-%d/%d", params.Start, params.End, size)) w.Header().Set(api.ContentLength, strconv.FormatUint(params.End-params.Start+1, 10)) w.WriteHeader(http.StatusPartialContent) }