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minio/httprange.go

134 lines
4.2 KiB

/*
* 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 (
"fmt"
"regexp"
"strconv"
"strings"
)
const (
byteRangePrefix = "bytes="
)
// Valid byte position regexp
var validBytePos = regexp.MustCompile(`^[0-9]+$`)
// HttpRange specifies the byte range to be sent to the client.
type httpRange struct {
offsetBegin int64
offsetEnd int64
resourceSize int64
}
// String populate range stringer interface
func (hrange httpRange) String() string {
return fmt.Sprintf("bytes %d-%d/%d", hrange.offsetBegin, hrange.offsetEnd, hrange.resourceSize)
}
// getlength - get length from the range.
func (hrange httpRange) getLength() int64 {
return 1 + hrange.offsetEnd - hrange.offsetBegin
}
func parseRequestRange(rangeString string, resourceSize 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. eg. "bytes=8"
sepIndex := strings.Index(byteRangeString, "-")
if sepIndex == -1 {
return nil, fmt.Errorf("'%s' does not have a valid range value", rangeString)
}
offsetBeginString := byteRangeString[:sepIndex]
offsetBegin := int64(-1)
// Convert offsetBeginString only if its not empty.
if len(offsetBeginString) > 0 {
if !validBytePos.MatchString(offsetBeginString) {
return nil, fmt.Errorf("'%s' does not have a valid first byte position value", rangeString)
}
if offsetBegin, err = strconv.ParseInt(offsetBeginString, 10, 64); err != nil {
return nil, fmt.Errorf("'%s' does not have a valid first byte position value", rangeString)
}
}
offsetEndString := byteRangeString[sepIndex+1:]
offsetEnd := int64(-1)
// Convert offsetEndString only if its not empty.
if len(offsetEndString) > 0 {
if !validBytePos.MatchString(offsetEndString) {
return nil, fmt.Errorf("'%s' does not have a valid last byte position value", rangeString)
}
if offsetEnd, err = strconv.ParseInt(offsetEndString, 10, 64); err != nil {
return nil, fmt.Errorf("'%s' does not have a valid last byte position value", rangeString)
}
}
// rangeString contains first and last byte positions. eg. "bytes=2-5"
if offsetBegin > -1 && offsetEnd > -1 {
if offsetBegin > offsetEnd {
// Last byte position is not greater than first byte position. eg. "bytes=5-2"
return nil, fmt.Errorf("'%s' does not have valid range value", rangeString)
}
// First and last byte positions should not be >= resourceSize.
if offsetBegin >= resourceSize {
return nil, errInvalidRange
}
if offsetEnd >= resourceSize {
offsetEnd = resourceSize - 1
}
} else if offsetBegin > -1 {
// rangeString contains only first byte position. eg. "bytes=8-"
if offsetBegin >= resourceSize {
// First byte position should not be >= resourceSize.
return nil, errInvalidRange
}
offsetEnd = resourceSize - 1
} else if offsetEnd > -1 {
// rangeString contains only last byte position. eg. "bytes=-3"
if offsetEnd == 0 {
// Last byte position should not be zero eg. "bytes=-0"
return nil, errInvalidRange
}
if offsetEnd >= resourceSize {
offsetBegin = 0
} else {
offsetBegin = resourceSize - offsetEnd
}
offsetEnd = resourceSize - 1
} else {
// rangeString contains first and last byte positions missing. eg. "bytes=-"
return nil, fmt.Errorf("'%s' does not have valid range value", rangeString)
}
return &httpRange{offsetBegin, offsetEnd, resourceSize}, nil
}