minio/httprange.go
2016-07-06 12:50:24 -07:00

116 lines
3.5 KiB
Go

/*
* Minio Cloud Storage, (C) 2015, 2016 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 (
byteRangePrefix = "bytes="
)
// errInvalidRange - returned when given range value is not valid.
var errInvalidRange = errors.New("Invalid range")
// InvalidRange - invalid range typed error.
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 {
firstBytePos int64
lastBytePos int64
size int64
}
// String populate range stringer interface
func (hrange httpRange) String() string {
return fmt.Sprintf("bytes %d-%d/%d", hrange.firstBytePos, hrange.lastBytePos, hrange.size)
}
// getLength - get length from the range.
func (hrange httpRange) getLength() int64 {
return 1 + hrange.lastBytePos - hrange.firstBytePos
}
func parseRequestRange(rangeString string, size int64) (hrange *httpRange, err error) {
// Return error if given range string doesn't start with byte range prefix.
if !strings.HasPrefix(rangeString, byteRangePrefix) {
return nil, fmt.Errorf("'%s' does not start with '%s'", rangeString, byteRangePrefix)
}
// Trim byte range prefix.
byteRangeString := strings.TrimPrefix(rangeString, byteRangePrefix)
// Check if range string contains delimiter '-', else return error.
sepIndex := strings.Index(byteRangeString, "-")
if sepIndex == -1 {
return nil, fmt.Errorf("invalid range string '%s'", rangeString)
}
firstBytePosString := byteRangeString[:sepIndex]
lastBytePosString := byteRangeString[sepIndex+1:]
firstBytePos := int64(-1)
lastBytePos := int64(-1)
// Convert firstBytePosString only if its not empty.
if len(firstBytePosString) > 0 {
if firstBytePos, err = strconv.ParseInt(firstBytePosString, 10, 64); err != nil {
return nil, fmt.Errorf("'%s' does not have valid first byte position value", rangeString)
}
}
// Convert lastBytePosString only if its not empty.
if len(lastBytePosString) > 0 {
if lastBytePos, err = strconv.ParseInt(lastBytePosString, 10, 64); err != nil {
return nil, fmt.Errorf("'%s' does not have valid last byte position value", rangeString)
}
}
// Return error if firstBytePosString and lastBytePosString are empty.
if firstBytePos == -1 && lastBytePos == -1 {
return nil, fmt.Errorf("'%s' does not have valid range value", rangeString)
}
if firstBytePos == -1 {
// Return error if lastBytePos is zero and firstBytePos is not given eg. "bytes=-0"
if lastBytePos == 0 {
return nil, errInvalidRange
}
firstBytePos = size - lastBytePos
lastBytePos = size - 1
} else if lastBytePos == -1 {
lastBytePos = size - 1
} else if firstBytePos > lastBytePos {
// Return error if firstBytePos is greater than lastBytePos
return nil, fmt.Errorf("'%s' does not have valid range value", rangeString)
} else if lastBytePos >= size {
// Set lastBytePos is out of size range.
lastBytePos = size - 1
}
return &httpRange{firstBytePos, lastBytePos, size}, nil
}