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