copyurl: fix copying files that return HTTP errors

fs/operations/operations.go

@@ -1575,11 +1575,13 @@ func RcatSize(ctx context.Context, fdst fs.Fs, dstFileName string, in io.ReadClo
 func CopyURL(ctx context.Context, fdst fs.Fs, dstFileName string, url string) (dst fs.Object, err error) {
 	client := fshttp.NewClient(fs.Config)
 	resp, err := client.Get(url)
-
 	if err != nil {
 		return nil, err
 	}
 	defer fs.CheckClose(resp.Body, &err)
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		return nil, errors.Errorf("CopyURL failed: %s", resp.Status)
+	}
 	return RcatSize(ctx, fdst, dstFileName, resp.Body, resp.ContentLength, time.Now())
 }
 

fs/operations/operations_test.go

@@ -695,7 +695,11 @@ func TestCopyURL(t *testing.T) {
 	fstest.CheckItems(t, r.Fremote)
 
 	// check when reading from regular HTTP server
+	status := 0
 	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if status != 0 {
+			http.Error(w, "an error ocurred", status)
+		}
 		_, err := w.Write([]byte(contents))
 		assert.NoError(t, err)
 	})
@@ -708,6 +712,14 @@ func TestCopyURL(t *testing.T) {
 
 	fstest.CheckListingWithPrecision(t, r.Fremote, []fstest.Item{file1}, nil, fs.ModTimeNotSupported)
 
+	// Check an error is returned for a 404
+	status = http.StatusNotFound
+	o, err = operations.CopyURL(context.Background(), r.Fremote, "file1", ts.URL)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "Not Found")
+	assert.Nil(t, o)
+	status = 0
+
 	// check when reading from unverified HTTPS server
 	fs.Config.InsecureSkipVerify = true
 	fshttp.ResetTransport()