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author | Matthew Heon <matthew.heon@gmail.com> | 2017-11-01 11:24:59 -0400 |
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committer | Matthew Heon <matthew.heon@gmail.com> | 2017-11-01 11:24:59 -0400 |
commit | a031b83a09a8628435317a03f199cdc18b78262f (patch) | |
tree | bc017a96769ce6de33745b8b0b1304ccf38e9df0 /vendor/github.com/docker/distribution/registry/client/transport/http_reader.go | |
parent | 2b74391cd5281f6fdf391ff8ad50fd1490f6bf89 (diff) | |
download | podman-a031b83a09a8628435317a03f199cdc18b78262f.tar.gz podman-a031b83a09a8628435317a03f199cdc18b78262f.tar.bz2 podman-a031b83a09a8628435317a03f199cdc18b78262f.zip |
Initial checkin from CRI-O repo
Signed-off-by: Matthew Heon <matthew.heon@gmail.com>
Diffstat (limited to 'vendor/github.com/docker/distribution/registry/client/transport/http_reader.go')
-rw-r--r-- | vendor/github.com/docker/distribution/registry/client/transport/http_reader.go | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/vendor/github.com/docker/distribution/registry/client/transport/http_reader.go b/vendor/github.com/docker/distribution/registry/client/transport/http_reader.go new file mode 100644 index 000000000..e5ff09d75 --- /dev/null +++ b/vendor/github.com/docker/distribution/registry/client/transport/http_reader.go @@ -0,0 +1,251 @@ +package transport + +import ( + "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. +type ReadSeekCloser interface { + io.ReadSeeker + io.Closer +} + +// NewHTTPReadSeeker handles reading from an HTTP endpoint using a GET +// request. When seeking and starting a read from a non-zero offset +// the a "Range" header will be added which sets the offset. +// TODO(dmcgowan): Move this into a separate utility package +func NewHTTPReadSeeker(client *http.Client, url string, errorHandler func(*http.Response) error) ReadSeekCloser { + return &httpReadSeeker{ + client: client, + url: url, + errorHandler: errorHandler, + } +} + +type httpReadSeeker struct { + client *http.Client + url string + + // errorHandler creates an error from an unsuccessful HTTP response. + // This allows the error to be created with the HTTP response body + // without leaking the body through a returned error. + errorHandler func(*http.Response) error + + size int64 + + // rc is the remote read closer. + rc io.ReadCloser + // readerOffset tracks the offset as of the last read. + readerOffset int64 + // seekOffset allows Seek to override the offset. Seek changes + // seekOffset instead of changing readOffset directly so that + // connection resets can be delayed and possibly avoided if the + // seek is undone (i.e. seeking to the end and then back to the + // beginning). + seekOffset int64 + err error +} + +func (hrs *httpReadSeeker) Read(p []byte) (n int, err error) { + if hrs.err != nil { + return 0, hrs.err + } + + // If we sought to a different position, we need to reset the + // connection. This logic is here instead of Seek so that if + // a seek is undone before the next read, the connection doesn't + // need to be closed and reopened. A common example of this is + // seeking to the end to determine the length, and then seeking + // back to the original position. + if hrs.readerOffset != hrs.seekOffset { + hrs.reset() + } + + hrs.readerOffset = hrs.seekOffset + + rd, err := hrs.reader() + if err != nil { + return 0, err + } + + n, err = rd.Read(p) + hrs.seekOffset += int64(n) + hrs.readerOffset += int64(n) + + return n, err +} + +func (hrs *httpReadSeeker) Seek(offset int64, whence int) (int64, error) { + if hrs.err != nil { + 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 + } + + newOffset := hrs.seekOffset + + switch whence { + case os.SEEK_CUR: + newOffset += offset + case os.SEEK_END: + if hrs.size < 0 { + return 0, errors.New("content length not known") + } + newOffset = hrs.size + offset + case os.SEEK_SET: + newOffset = offset + } + + if newOffset < 0 { + err = errors.New("cannot seek to negative position") + } else { + hrs.seekOffset = newOffset + } + + return hrs.seekOffset, err +} + +func (hrs *httpReadSeeker) Close() error { + if hrs.err != nil { + return hrs.err + } + + // close and release reader chain + if hrs.rc != nil { + hrs.rc.Close() + } + + hrs.rc = nil + + hrs.err = errors.New("httpLayer: closed") + + return nil +} + +func (hrs *httpReadSeeker) reset() { + if hrs.err != nil { + return + } + if hrs.rc != nil { + hrs.rc.Close() + hrs.rc = nil + } +} + +func (hrs *httpReadSeeker) reader() (io.Reader, error) { + if hrs.err != nil { + return nil, hrs.err + } + + if hrs.rc != nil { + return hrs.rc, nil + } + + req, err := http.NewRequest("GET", hrs.url, nil) + if err != nil { + return nil, err + } + + if hrs.readerOffset > 0 { + // If we are at different offset, issue a range request from there. + 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")) + } + + req.Header.Add("Accept-Encoding", "identity") + resp, err := hrs.client.Do(req) + if err != nil { + return nil, err + } + + // Normally would use client.SuccessStatus, but that would be a cyclic + // import + if resp.StatusCode >= 200 && resp.StatusCode <= 399 { + 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 { + return nil, hrs.errorHandler(resp) + } + return nil, fmt.Errorf("unexpected status resolving reader: %v", resp.Status) + } + + return hrs.rc, nil +} |