Write to byte buffer first, then to response (#694)

* Write to byte buffer first, then to response

* Fix golint

* Another lint fix

fakestorage/server.go

@@ -11,6 +11,7 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"mime"
 	"mime/multipart"
 	"net"
@@ -26,6 +27,7 @@ import (
 	"github.com/fsouza/fake-gcs-server/internal/notification"
 	"github.com/gorilla/handlers"
 	"github.com/gorilla/mux"
+	"github.com/sirupsen/logrus"
 	"golang.org/x/oauth2/google"
 	"google.golang.org/api/option"
 )
@@ -308,7 +310,8 @@ func (s *Server) handleBatchCall(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	mw := multipart.NewWriter(w)
+	var b bytes.Buffer
+	mw := multipart.NewWriter(&b)
 	defer mw.Close()
 	w.Header().Set("Content-Type", "multipart/mixed; boundary="+mw.Boundary())
 
@@ -337,7 +340,8 @@ func (s *Server) handleBatchCall(w http.ResponseWriter, r *http.Request) {
 			continue
 		}
 
-		content, err := loadContent(part)
+		content, err := ioutil.ReadAll(part)
+		part.Close()
 		if err != nil {
 			http.Error(partResponseWriter, "unable to process request", http.StatusBadRequest)
 			writeMultipartResponse(partResponseWriter.Result(), partWriter, contentID)
@@ -354,6 +358,13 @@ func (s *Server) handleBatchCall(w http.ResponseWriter, r *http.Request) {
 		s.mux.ServeHTTP(partResponseWriter, partRequest)
 		writeMultipartResponse(partResponseWriter.Result(), partWriter, contentID)
 	}
+	mw.Close()
+
+	_, err = b.WriteTo(w)
+	if err != nil {
+		logrus.New().Error(err)
+		http.Error(w, "unable to process request", http.StatusBadRequest)
+	}
 }
 
 func writeMultipartResponse(r *http.Response, w io.Writer, contentId string) {