120 lines
2.8 KiB
Go
120 lines
2.8 KiB
Go
/*
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* Minimalist Object Storage, (C) 2015 Minio, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package api
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import (
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"errors"
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"fmt"
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"strconv"
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"strings"
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"net/http"
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)
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const (
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b = "bytes="
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)
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// HttpRange specifies the byte range to be sent to the client.
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type httpRange struct {
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start, length, size int64
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}
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// GetContentRange populate range header
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func (r *httpRange) getContentRange() string {
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return fmt.Sprintf("bytes %d-%d/%d", r.start, r.start+r.length-1, r.size)
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}
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// Grab new range from request header
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func newRange(req *http.Request, size int64) (*httpRange, error) {
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r := &httpRange{
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start: 0,
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length: 0,
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size: 0,
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}
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r.size = size
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if s := req.Header.Get("Range"); s != "" {
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err := r.parseRange(s)
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if err != nil {
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return nil, err
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}
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}
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return r, nil
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}
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// parseRange parses a Range header string as per RFC 2616.
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func (r *httpRange) parseRange(s string) error {
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if s == "" {
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return errors.New("header not present")
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}
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if !strings.HasPrefix(s, b) {
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return errors.New("invalid range")
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}
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ras := strings.Split(s[len(b):], ",")
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if len(ras) == 0 {
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return errors.New("invalid request")
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}
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// Just pick the first one and ignore the rest, we only support one range per object
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if len(ras) > 1 {
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return errors.New("multiple ranges specified")
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}
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ra := strings.TrimSpace(ras[0])
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if ra == "" {
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return errors.New("invalid range")
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}
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i := strings.Index(ra, "-")
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if i < 0 {
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return errors.New("invalid range")
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}
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start, end := strings.TrimSpace(ra[:i]), strings.TrimSpace(ra[i+1:])
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if start == "" {
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// If no start is specified, end specifies the
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// range start relative to the end of the file.
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i, err := strconv.ParseInt(end, 10, 64)
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if err != nil {
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return errors.New("invalid range")
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}
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if i > r.size {
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i = r.size
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}
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r.start = r.size - i
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r.length = r.size - r.start
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} else {
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i, err := strconv.ParseInt(start, 10, 64)
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if err != nil || i > r.size || i < 0 {
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return errors.New("invalid range")
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}
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r.start = i
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if end == "" {
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// If no end is specified, range extends to end of the file.
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r.length = r.size - r.start
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} else {
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i, err := strconv.ParseInt(end, 10, 64)
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if err != nil || r.start > i {
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return errors.New("invalid range")
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}
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if i >= r.size {
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i = r.size - 1
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}
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r.length = i - r.start + 1
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}
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}
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return nil
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}
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