[#163] Fix zip streaming

Signed-off-by: Denis Kirillov <denis@nspcc.ru>

downloader/download.go

@@ -2,6 +2,7 @@ package downloader
 
 import (
 	"archive/zip"
+	"bufio"
 	"bytes"
 	"context"
 	"errors"
@@ -383,6 +384,19 @@ func (d *Downloader) search(c *fasthttp.RequestCtx, cid *cid.ID, key, val string
 	return d.pool.SearchObjects(d.appCtx, prm)
 }
 
+func (d *Downloader) addObjectToZip(zw *zip.Writer, obj *object.Object) (io.Writer, error) {
+	method := zip.Store
+	if d.settings.ZipCompression {
+		method = zip.Deflate
+	}
+
+	return zw.CreateHeader(&zip.FileHeader{
+		Name:     getZipFilePath(obj),
+		Method:   method,
+		Modified: time.Now(),
+	})
+}
+
 // DownloadZipped handles zip by prefix requests.
 func (d *Downloader) DownloadZipped(c *fasthttp.RequestCtx) {
 	scid, _ := c.UserValue("cid").(string)
@@ -409,75 +423,33 @@ func (d *Downloader) DownloadZipped(c *fasthttp.RequestCtx) {
 		return
 	}
 
-	defer resSearch.Close()
-
 	c.Response.Header.Set(fasthttp.HeaderContentType, "application/zip")
 	c.Response.Header.Set(fasthttp.HeaderContentDisposition, "attachment; filename=\"archive.zip\"")
 	c.Response.SetStatusCode(http.StatusOK)
 
-	zipWriter := zip.NewWriter(c)
-	compression := zip.Store
-	if d.settings.ZipCompression {
-		compression = zip.Deflate
-	}
+	c.SetBodyStreamWriter(func(w *bufio.Writer) {
+		defer resSearch.Close()
 
-	var (
-		addr   address.Address
-		resGet *pool.ResGetObject
-		w      io.Writer
-		bufZip []byte
-	)
+		zipWriter := zip.NewWriter(w)
 
-	addr.SetContainerID(*containerID)
+		var bufZip []byte
+		var addr address.Address
 
-	btoken := bearerToken(c)
 		empty := true
 		called := false
+		btoken := bearerToken(c)
+		addr.SetContainerID(*containerID)
 
 		errIter := resSearch.Iterate(func(id oid.ID) bool {
 			called = true
 
 			if empty {
-			bufZip = make([]byte, 1024) // configure?
+				bufZip = make([]byte, 3<<20) // the same as for upload
 			}
-
 			empty = false
 
 			addr.SetObjectID(id)
-
-		var prm pool.PrmObjectGet
-		prm.SetAddress(addr)
-		if btoken != nil {
-			prm.UseBearer(*btoken)
-		}
-
-		resGet, err = d.pool.GetObject(d.appCtx, prm)
-		if err != nil {
-			err = fmt.Errorf("get NeoFS object: %v", err)
-			return true
-		}
-
-		w, err = zipWriter.CreateHeader(&zip.FileHeader{
-			Name:     getZipFilePath(&resGet.Header),
-			Method:   compression,
-			Modified: time.Now(),
-		})
-		if err != nil {
-			err = fmt.Errorf("zip create header: %v", err)
-			return true
-		}
-
-		_, err = io.CopyBuffer(w, resGet.Payload, bufZip)
-		if err != nil {
-			err = fmt.Errorf("copy object payload to zip file: %v", err)
-			return true
-		}
-
-		_ = resGet.Payload.Close()
-
-		err = zipWriter.Flush()
-		if err != nil {
-			err = fmt.Errorf("flush zip writer: %v", err)
+			if err = d.zipObject(zipWriter, addr, btoken, bufZip); err != nil {
 				return true
 			}
 
@@ -502,6 +474,39 @@ func (d *Downloader) DownloadZipped(c *fasthttp.RequestCtx) {
 			response.Error(c, "file streaming failure: "+err.Error(), fasthttp.StatusInternalServerError)
 			return
 		}
+	})
+}
+
+func (d *Downloader) zipObject(zipWriter *zip.Writer, addr address.Address, btoken *bearer.Token, bufZip []byte) error {
+	var prm pool.PrmObjectGet
+	prm.SetAddress(addr)
+	if btoken != nil {
+		prm.UseBearer(*btoken)
+	}
+
+	resGet, err := d.pool.GetObject(d.appCtx, prm)
+	if err != nil {
+		return fmt.Errorf("get NeoFS object: %v", err)
+	}
+
+	objWriter, err := d.addObjectToZip(zipWriter, &resGet.Header)
+	if err != nil {
+		return fmt.Errorf("zip create header: %v", err)
+	}
+
+	if _, err = io.CopyBuffer(objWriter, resGet.Payload, bufZip); err != nil {
+		return fmt.Errorf("copy object payload to zip file: %v", err)
+	}
+
+	if err = resGet.Payload.Close(); err != nil {
+		return fmt.Errorf("object body close error: %w", err)
+	}
+
+	if err = zipWriter.Flush(); err != nil {
+		return fmt.Errorf("flush zip writer: %v", err)
+	}
+
+	return nil
 }
 
 func getZipFilePath(obj *object.Object) string {

integration_test.go

@@ -276,7 +276,7 @@ func makeZipRequest(t *testing.T, url string, names, contents []string) {
 
 	data, err := io.ReadAll(resp.Body)
 	require.NoError(t, err)
-	checkZip(t, data, resp.ContentLength, names, contents)
+	checkZip(t, data, int64(len(data)), names, contents)
 }
 
 func checkZip(t *testing.T, data []byte, length int64, names, contents []string) {