Merge pull request #1392 from aaronlehmann/client-range-requests

Support range requests in the client's httpReadSeeker
This commit is contained in:
Derek McGowan 2016-01-28 13:44:43 -08:00
commit 70e85dde26
2 changed files with 97 additions and 28 deletions

View file

@ -27,6 +27,26 @@ type Registry interface {
Repositories(ctx context.Context, repos []string, last string) (n int, err error)
}
// checkHTTPRedirect is a callback that can manipulate redirected HTTP
// requests. It is used to preserve Accept and Range headers.
func checkHTTPRedirect(req *http.Request, via []*http.Request) error {
if len(via) >= 10 {
return errors.New("stopped after 10 redirects")
}
if len(via) > 0 {
for headerName, headerVals := range via[0].Header {
if headerName == "Accept" || headerName == "Range" {
for _, val := range headerVals {
req.Header.Add(headerName, val)
}
}
}
}
return nil
}
// NewRegistry creates a registry namespace which can be used to get a listing of repositories
func NewRegistry(ctx context.Context, baseURL string, transport http.RoundTripper) (Registry, error) {
ub, err := v2.NewURLBuilderFromString(baseURL)
@ -35,8 +55,9 @@ func NewRegistry(ctx context.Context, baseURL string, transport http.RoundTrippe
}
client := &http.Client{
Transport: transport,
Timeout: 1 * time.Minute,
Transport: transport,
Timeout: 1 * time.Minute,
CheckRedirect: checkHTTPRedirect,
}
return &registry{
@ -105,7 +126,8 @@ func NewRepository(ctx context.Context, name reference.Named, baseURL string, tr
}
client := &http.Client{
Transport: transport,
Transport: transport,
CheckRedirect: checkHTTPRedirect,
// TODO(dmcgowan): create cookie jar
}

View file

@ -1,12 +1,22 @@
package transport
import (
"bufio"
"errors"
"fmt"
"io"
"net/http"
"os"
"regexp"
"strconv"
)
var (
contentRangeRegexp = regexp.MustCompile(`bytes ([0-9]+)-([0-9]+)/([0-9]+|\\*)`)
// ErrWrongCodeForByteRange is returned if the client sends a request
// with a Range header but the server returns a 2xx or 3xx code other
// than 206 Partial Content.
ErrWrongCodeForByteRange = errors.New("expected HTTP 206 from byte range request")
)
// ReadSeekCloser combines io.ReadSeeker with io.Closer.
@ -40,8 +50,6 @@ type httpReadSeeker struct {
// rc is the remote read closer.
rc io.ReadCloser
// brd is a buffer for internal buffered io.
brd *bufio.Reader
// readerOffset tracks the offset as of the last read.
readerOffset int64
// seekOffset allows Seek to override the offset. Seek changes
@ -79,11 +87,6 @@ func (hrs *httpReadSeeker) Read(p []byte) (n int, err error) {
hrs.seekOffset += int64(n)
hrs.readerOffset += int64(n)
// Simulate io.EOF error if we reach filesize.
if err == nil && hrs.size >= 0 && hrs.readerOffset >= hrs.size {
err = io.EOF
}
return n, err
}
@ -92,8 +95,18 @@ func (hrs *httpReadSeeker) Seek(offset int64, whence int) (int64, error) {
return 0, hrs.err
}
lastReaderOffset := hrs.readerOffset
if whence == os.SEEK_SET && hrs.rc == nil {
// If no request has been made yet, and we are seeking to an
// absolute position, set the read offset as well to avoid an
// unnecessary request.
hrs.readerOffset = offset
}
_, err := hrs.reader()
if err != nil {
hrs.readerOffset = lastReaderOffset
return 0, err
}
@ -101,14 +114,14 @@ func (hrs *httpReadSeeker) Seek(offset int64, whence int) (int64, error) {
switch whence {
case os.SEEK_CUR:
newOffset += int64(offset)
newOffset += offset
case os.SEEK_END:
if hrs.size < 0 {
return 0, errors.New("content length not known")
}
newOffset = hrs.size + int64(offset)
newOffset = hrs.size + offset
case os.SEEK_SET:
newOffset = int64(offset)
newOffset = offset
}
if newOffset < 0 {
@ -131,7 +144,6 @@ func (hrs *httpReadSeeker) Close() error {
}
hrs.rc = nil
hrs.brd = nil
hrs.err = errors.New("httpLayer: closed")
@ -154,7 +166,7 @@ func (hrs *httpReadSeeker) reader() (io.Reader, error) {
}
if hrs.rc != nil {
return hrs.brd, nil
return hrs.rc, nil
}
req, err := http.NewRequest("GET", hrs.url, nil)
@ -163,10 +175,8 @@ func (hrs *httpReadSeeker) reader() (io.Reader, error) {
}
if hrs.readerOffset > 0 {
// TODO(stevvooe): Get this working correctly.
// If we are at different offset, issue a range request from there.
req.Header.Add("Range", "1-")
req.Header.Add("Range", fmt.Sprintf("bytes=%d-", hrs.readerOffset))
// TODO: get context in here
// context.GetLogger(hrs.context).Infof("Range: %s", req.Header.Get("Range"))
}
@ -179,12 +189,55 @@ func (hrs *httpReadSeeker) reader() (io.Reader, error) {
// Normally would use client.SuccessStatus, but that would be a cyclic
// import
if resp.StatusCode >= 200 && resp.StatusCode <= 399 {
hrs.rc = resp.Body
if resp.StatusCode == http.StatusOK {
if hrs.readerOffset > 0 {
if resp.StatusCode != http.StatusPartialContent {
return nil, ErrWrongCodeForByteRange
}
contentRange := resp.Header.Get("Content-Range")
if contentRange == "" {
return nil, errors.New("no Content-Range header found in HTTP 206 response")
}
submatches := contentRangeRegexp.FindStringSubmatch(contentRange)
if len(submatches) < 4 {
return nil, fmt.Errorf("could not parse Content-Range header: %s", contentRange)
}
startByte, err := strconv.ParseUint(submatches[1], 10, 64)
if err != nil {
return nil, fmt.Errorf("could not parse start of range in Content-Range header: %s", contentRange)
}
if startByte != uint64(hrs.readerOffset) {
return nil, fmt.Errorf("received Content-Range starting at offset %d instead of requested %d", startByte, hrs.readerOffset)
}
endByte, err := strconv.ParseUint(submatches[2], 10, 64)
if err != nil {
return nil, fmt.Errorf("could not parse end of range in Content-Range header: %s", contentRange)
}
if submatches[3] == "*" {
hrs.size = -1
} else {
size, err := strconv.ParseUint(submatches[3], 10, 64)
if err != nil {
return nil, fmt.Errorf("could not parse total size in Content-Range header: %s", contentRange)
}
if endByte+1 != size {
return nil, fmt.Errorf("range in Content-Range stops before the end of the content: %s", contentRange)
}
hrs.size = int64(size)
}
} else if resp.StatusCode == http.StatusOK {
hrs.size = resp.ContentLength
} else {
hrs.size = -1
}
hrs.rc = resp.Body
} else {
defer resp.Body.Close()
if hrs.errorHandler != nil {
@ -193,11 +246,5 @@ func (hrs *httpReadSeeker) reader() (io.Reader, error) {
return nil, fmt.Errorf("unexpected status resolving reader: %v", resp.Status)
}
if hrs.brd == nil {
hrs.brd = bufio.NewReader(hrs.rc)
} else {
hrs.brd.Reset(hrs.rc)
}
return hrs.brd, nil
return hrs.rc, nil
}