// ServeBlobRef serves a blob.
func ServeBlobRef(rw http.ResponseWriter, req *http.Request, blobRef blob.Ref, fetcher blob.Fetcher) {
rc, size, err := fetcher.Fetch(blobRef)
switch err {
case nil:
break
case os.ErrNotExist:
rw.WriteHeader(http.StatusNotFound)
fmt.Fprintf(rw, "Blob %q not found", blobRef)
return
default:
httputil.ServeError(rw, req, err)
return
}
defer rc.Close()
rw.Header().Set("Content-Type", "application/octet-stream")
var content io.ReadSeeker = readerutil.NewFakeSeeker(rc, int64(size))
rangeHeader := req.Header.Get("Range") != ""
const small = 32 << 10
var b *blob.Blob
if rangeHeader || size < small {
// Slurp to memory, so we can actually seek on it (for Range support),
// or if we're going to be showing it in the browser (below).
b, err = blob.FromReader(blobRef, rc, size)
if err != nil {
httputil.ServeError(rw, req, err)
return
}
content = b.Open()
}
if !rangeHeader && size < small {
// If it's small and all UTF-8, assume it's text and
// just render it in the browser. This is more for
// demos/debuggability than anything else. It isn't
// part of the spec.
if b.IsUTF8() {
rw.Header().Set("Content-Type", "text/plain; charset=utf-8")
}
}
http.ServeContent(rw, req, "", dummyModTime, content)
}
func verifySizeAndHash(t *testing.T, blob *blob.Blob) {
hash := sha1.New()
r := blob.Open()
n, err := io.Copy(hash, r)
if err != nil {
t.Fatal(err)
}
r.Close()
if uint32(n) != blob.Size() {
t.Fatalf("read %d bytes from blob %v; want %v", n, blob.Ref(), blob.Size())
}
if !blob.SizedRef().HashMatches(hash) {
t.Fatalf("read wrong bytes from blobref %v (digest mismatch)", blob.Ref())
}
}