gtsocial-umbx

request-signature-streaming-unsigned-trailer.go (6805B)

---

 /*
  * 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()
 }