distribution/docs/storage/blobserver.go
Richard Scothern 6d46ae5fdb Prevent the ErrUnsupportedMethod error from being returned up the stack.
It eventually causes the go http library to do a double WriteHeader()
which is an error

Signed-off-by: Richard Scothern <richard.scothern@gmail.com>
2015-06-29 16:44:09 -07:00

73 lines
2 KiB
Go

package storage
import (
"fmt"
"net/http"
"time"
"github.com/docker/distribution"
"github.com/docker/distribution/context"
"github.com/docker/distribution/digest"
"github.com/docker/distribution/registry/storage/driver"
)
// TODO(stevvooe): This should configurable in the future.
const blobCacheControlMaxAge = 365 * 24 * time.Hour
// blobServer simply serves blobs from a driver instance using a path function
// to identify paths and a descriptor service to fill in metadata.
type blobServer struct {
driver driver.StorageDriver
statter distribution.BlobStatter
pathFn func(dgst digest.Digest) (string, error)
}
func (bs *blobServer) ServeBlob(ctx context.Context, w http.ResponseWriter, r *http.Request, dgst digest.Digest) error {
desc, err := bs.statter.Stat(ctx, dgst)
if err != nil {
return err
}
path, err := bs.pathFn(desc.Digest)
if err != nil {
return err
}
redirectURL, err := bs.driver.URLFor(ctx, path, map[string]interface{}{"method": r.Method})
switch err {
case nil:
// Redirect to storage URL.
http.Redirect(w, r, redirectURL, http.StatusTemporaryRedirect)
case driver.ErrUnsupportedMethod:
// Fallback to serving the content directly.
br, err := newFileReader(ctx, bs.driver, path, desc.Length)
if err != nil {
return err
}
defer br.Close()
w.Header().Set("ETag", desc.Digest.String()) // If-None-Match handled by ServeContent
w.Header().Set("Cache-Control", fmt.Sprintf("max-age=%.f", blobCacheControlMaxAge.Seconds()))
if w.Header().Get("Docker-Content-Digest") == "" {
w.Header().Set("Docker-Content-Digest", desc.Digest.String())
}
if w.Header().Get("Content-Type") == "" {
// Set the content type if not already set.
w.Header().Set("Content-Type", desc.MediaType)
}
if w.Header().Get("Content-Length") == "" {
// Set the content length if not already set.
w.Header().Set("Content-Length", fmt.Sprint(desc.Length))
}
http.ServeContent(w, r, desc.Digest.String(), time.Time{}, br)
return nil
}
// Some unexpected error.
return err
}