diff --git a/lib/go/camli/blobref/fetcher.go b/lib/go/camli/blobref/fetcher.go
index 79cb73d00..51623eb18 100644
--- a/lib/go/camli/blobref/fetcher.go
+++ b/lib/go/camli/blobref/fetcher.go
@@ -178,3 +178,17 @@ func (s *MemoryStore) FetchStreaming(b *BlobRef) (file io.ReadCloser, size int64
 	}
 	return ioutil.NopCloser(strings.NewReader(str)), int64(len(str)), nil
 }
+
+func SeekerFromStreamingFetcher(f StreamingFetcher) (SeekFetcher, os.Error) {
+	seeker, ok := f.(SeekFetcher)
+	if ok {
+		return seeker, nil
+	}
+	tester, ok := f.(SeekTester)
+	if ok {
+		if tester.IsFetcherASeeker() {
+			return &FetcherToSeekerWrapper{f}, nil
+		}
+	}
+	return nil, fmt.Errorf("bloref: TODO: SeekerFromStreamingFetcher: %T %v doesn't support seeking. TODO: wrap in a write-to-disk-and-read wrapper and/or cache", f, f)
+}
\ No newline at end of file
diff --git a/server/go/camlistored/ui.go b/server/go/camlistored/ui.go
index 9cc428ec5..68ad03c95 100644
--- a/server/go/camlistored/ui.go
+++ b/server/go/camlistored/ui.go
@@ -250,19 +250,7 @@ func (ui *UIHandler) serveUploadHelper(rw http.ResponseWriter, req *http.Request
 }
 
 func (ui *UIHandler) storageSeekFetcher() (blobref.SeekFetcher, os.Error) {
-	fetchSeeker, ok := ui.Storage.(blobref.SeekFetcher)
-	if ok {
-		return fetchSeeker, nil
-	}
-	tester, ok := ui.Storage.(blobref.SeekTester)
-	if ok {
-		if tester.IsFetcherASeeker() {
-			log.Printf("ui.Storage is a seeker; returning wrapper")
-			return &blobref.FetcherToSeekerWrapper{ui.Storage}, nil
-		}
-	}
-	return nil, fmt.Errorf("TODO: ui.Storage of %T %v doesn't support seeking. TODO: wrap in a cache",
-		ui.Storage, ui.Storage)
+	return blobref.SeekerFromStreamingFetcher(ui.Storage)
 }
 
 func (ui *UIHandler) serveDownload(rw http.ResponseWriter, req *http.Request) {