gotosocial/vendor/github.com/minio/minio-go/v7/pkg/signer/request-signature-streaming-unsigned-trailer.go

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/*
* MinIO Go Library for Amazon S3 Compatible Cloud Storage
* Copyright 2022 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 signer
import (
"bytes"
"fmt"
"io"
"net/http"
"strconv"
"strings"
"time"
)
// getUnsignedChunkLength - calculates the length of chunk metadata
func getUnsignedChunkLength(chunkDataSize int64) int64 {
return int64(len(fmt.Sprintf("%x", chunkDataSize))) +
crlfLen +
chunkDataSize +
crlfLen
}
// getUSStreamLength - calculates the length of the overall stream (data + metadata)
func getUSStreamLength(dataLen, chunkSize int64, trailers http.Header) int64 {
if dataLen <= 0 {
return 0
}
chunksCount := int64(dataLen / chunkSize)
remainingBytes := int64(dataLen % chunkSize)
streamLen := int64(0)
streamLen += chunksCount * getUnsignedChunkLength(chunkSize)
if remainingBytes > 0 {
streamLen += getUnsignedChunkLength(remainingBytes)
}
streamLen += getUnsignedChunkLength(0)
if len(trailers) > 0 {
for name, placeholder := range trailers {
if len(placeholder) > 0 {
streamLen += int64(len(name) + len(trailerKVSeparator) + len(placeholder[0]) + 1)
}
}
streamLen += crlfLen
}
return streamLen
}
// prepareStreamingRequest - prepares a request with appropriate
// headers before computing the seed signature.
func prepareUSStreamingRequest(req *http.Request, sessionToken string, dataLen int64, timestamp time.Time) {
req.TransferEncoding = []string{"aws-chunked"}
if sessionToken != "" {
req.Header.Set("X-Amz-Security-Token", sessionToken)
}
req.Header.Set("X-Amz-Date", timestamp.Format(iso8601DateFormat))
// Set content length with streaming signature for each chunk included.
req.ContentLength = getUSStreamLength(dataLen, int64(payloadChunkSize), req.Trailer)
}
// StreamingUSReader implements chunked upload signature as a reader on
// top of req.Body's ReaderCloser chunk header;data;... repeat
type StreamingUSReader struct {
contentLen int64 // Content-Length from req header
baseReadCloser io.ReadCloser // underlying io.Reader
bytesRead int64 // bytes read from underlying io.Reader
buf bytes.Buffer // holds signed chunk
chunkBuf []byte // holds raw data read from req Body
chunkBufLen int // no. of bytes read so far into chunkBuf
done bool // done reading the underlying reader to EOF
chunkNum int
totalChunks int
lastChunkSize int
trailer http.Header
}
// writeChunk - signs a chunk read from s.baseReader of chunkLen size.
func (s *StreamingUSReader) writeChunk(chunkLen int, addCrLf bool) {
s.buf.WriteString(strconv.FormatInt(int64(chunkLen), 16) + "\r\n")
// Write chunk data into streaming buffer
s.buf.Write(s.chunkBuf[:chunkLen])
// Write the chunk trailer.
if addCrLf {
s.buf.Write([]byte("\r\n"))
}
// Reset chunkBufLen for next chunk read.
s.chunkBufLen = 0
s.chunkNum++
}
// addSignedTrailer - adds a trailer with the provided headers,
// then signs a chunk and adds it to output.
func (s *StreamingUSReader) addTrailer(h http.Header) {
olen := len(s.chunkBuf)
s.chunkBuf = s.chunkBuf[:0]
for k, v := range h {
s.chunkBuf = append(s.chunkBuf, []byte(strings.ToLower(k)+trailerKVSeparator+v[0]+"\n")...)
}
s.buf.Write(s.chunkBuf)
s.buf.WriteString("\r\n\r\n")
// Reset chunkBufLen for next chunk read.
s.chunkBuf = s.chunkBuf[:olen]
s.chunkBufLen = 0
s.chunkNum++
}
// StreamingUnsignedV4 - provides chunked upload
func StreamingUnsignedV4(req *http.Request, sessionToken string, dataLen int64, reqTime time.Time) *http.Request {
// Set headers needed for streaming signature.
prepareUSStreamingRequest(req, sessionToken, dataLen, reqTime)
if req.Body == nil {
req.Body = io.NopCloser(bytes.NewReader([]byte("")))
}
stReader := &StreamingUSReader{
baseReadCloser: req.Body,
chunkBuf: make([]byte, payloadChunkSize),
contentLen: dataLen,
chunkNum: 1,
totalChunks: int((dataLen+payloadChunkSize-1)/payloadChunkSize) + 1,
lastChunkSize: int(dataLen % payloadChunkSize),
}
if len(req.Trailer) > 0 {
stReader.trailer = req.Trailer
// Remove...
req.Trailer = nil
}
req.Body = stReader
return req
}
// Read - this method performs chunk upload signature providing a
// io.Reader interface.
func (s *StreamingUSReader) Read(buf []byte) (int, error) {
switch {
// After the last chunk is read from underlying reader, we
// never re-fill s.buf.
case s.done:
// s.buf will be (re-)filled with next chunk when has lesser
// bytes than asked for.
case s.buf.Len() < len(buf):
s.chunkBufLen = 0
for {
n1, err := s.baseReadCloser.Read(s.chunkBuf[s.chunkBufLen:])
// Usually we validate `err` first, but in this case
// we are validating n > 0 for the following reasons.
//
// 1. n > 0, err is one of io.EOF, nil (near end of stream)
// A Reader returning a non-zero number of bytes at the end
// of the input stream may return either err == EOF or err == nil
//
// 2. n == 0, err is io.EOF (actual end of stream)
//
// Callers should always process the n > 0 bytes returned
// before considering the error err.
if n1 > 0 {
s.chunkBufLen += n1
s.bytesRead += int64(n1)
if s.chunkBufLen == payloadChunkSize ||
(s.chunkNum == s.totalChunks-1 &&
s.chunkBufLen == s.lastChunkSize) {
// Sign the chunk and write it to s.buf.
s.writeChunk(s.chunkBufLen, true)
break
}
}
if err != nil {
if err == io.EOF {
// No more data left in baseReader - last chunk.
// Done reading the last chunk from baseReader.
s.done = true
// bytes read from baseReader different than
// content length provided.
if s.bytesRead != s.contentLen {
return 0, fmt.Errorf("http: ContentLength=%d with Body length %d", s.contentLen, s.bytesRead)
}
// Sign the chunk and write it to s.buf.
s.writeChunk(0, len(s.trailer) == 0)
if len(s.trailer) > 0 {
// Trailer must be set now.
s.addTrailer(s.trailer)
}
break
}
return 0, err
}
}
}
return s.buf.Read(buf)
}
// Close - this method makes underlying io.ReadCloser's Close method available.
func (s *StreamingUSReader) Close() error {
return s.baseReadCloser.Close()
}