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Copy pathhttprange.go
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128 lines (116 loc) · 2.88 KB
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Copy pathhttprange.go
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128 lines (116 loc) · 2.88 KB
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/*
* Minio Cloud Storage, (C) 2015 Minio, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package main
import (
"errors"
"fmt"
"strconv"
"strings"
)
const (
b = "bytes="
)
// InvalidRange - invalid range
type InvalidRange struct{}
func (e InvalidRange) Error() string {
return "The requested range is not satisfiable"
}
// HttpRange specifies the byte range to be sent to the client.
type httpRange struct {
start, length, size int64
}
// String populate range stringer interface
func (r *httpRange) String() string {
return fmt.Sprintf("bytes %d-%d/%d", r.start, r.start+r.length-1, r.size)
}
// Grab new range from request header
func getRequestedRange(hrange string, size int64) (*httpRange, error) {
r := &httpRange{
start: 0,
length: 0,
size: 0,
}
r.size = size
if hrange != "" {
err := r.parseRange(hrange)
if err != nil {
return nil, err
}
}
return r, nil
}
func (r *httpRange) parse(ra string) error {
i := strings.Index(ra, "-")
if i < 0 {
return InvalidRange{}
}
start, end := strings.TrimSpace(ra[:i]), strings.TrimSpace(ra[i+1:])
if start == "" {
// If no start is specified, end specifies the
// range start relative to the end of the file.
i, err := strconv.ParseInt(end, 10, 64)
if err != nil {
return InvalidRange{}
}
if i > r.size {
i = r.size
}
r.start = r.size - i
r.length = r.size - r.start
} else {
i, err := strconv.ParseInt(start, 10, 64)
if err != nil || i > r.size || i < 0 {
return InvalidRange{}
}
r.start = i
if end == "" {
// If no end is specified, range extends to end of the file.
r.length = r.size - r.start
} else {
i, err := strconv.ParseInt(end, 10, 64)
if err != nil || r.start > i {
return InvalidRange{}
}
if i >= r.size {
i = r.size - 1
}
r.length = i - r.start + 1
}
}
return nil
}
// parseRange parses a Range header string as per RFC 2616.
func (r *httpRange) parseRange(s string) error {
if s == "" {
return errors.New("header not present")
}
if !strings.HasPrefix(s, b) {
return InvalidRange{}
}
ras := strings.Split(s[len(b):], ",")
if len(ras) == 0 {
return errors.New("invalid request")
}
// Just pick the first one and ignore the rest, we only support one range per object
if len(ras) > 1 {
return errors.New("multiple ranges specified")
}
ra := strings.TrimSpace(ras[0])
if ra == "" {
return InvalidRange{}
}
return r.parse(ra)
}