diff --git a/.gitignore b/.gitignore
index 1705cd8..afc7549 100644
--- a/.gitignore
+++ b/.gitignore
@@ -17,3 +17,4 @@
 vendor
 coverage.out
 test.sh
+tmp*
diff --git a/.travis.yml b/.travis.yml
index 40efd9d..370d5a6 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,7 +1,6 @@
 language: go
 
 go:
-  - 1.11
   - 1.12
   - 1.13
 
@@ -15,7 +14,6 @@ env:
 before_script:
   - go get -u github.com/mattn/goveralls
   - cd $HOME
-  - mkdir -p $HOME/gopath/src/github.com/chrislusf/seaweedfs
   - mkdir -p /tmp/sw/master/metadata
   - mkdir -p /tmp/sw/volume1/data
   - mkdir -p /tmp/sw/filer
diff --git a/filer.go b/filer.go
index c62d477..8243710 100644
--- a/filer.go
+++ b/filer.go
@@ -42,10 +42,6 @@ func newFiler(u string, client *httpClient) (f *Filer, err error) {
 	return
 }
 
-var dirHeader = map[string]string{
-	"Accept": "application/json",
-}
-
 // Close underlying daemons.
 func (f *Filer) Close() (err error) {
 	if f.client != nil {
diff --git a/seaweed.go b/seaweed.go
index fdba0f3..c2c9e47 100644
--- a/seaweed.go
+++ b/seaweed.go
@@ -209,7 +209,7 @@ func (c *Seaweed) LookupServerByFileID(fileID string, args url.Values, readonly
 
 	if err == nil {
 		if readonly {
-			server = lookup.VolumeLocations.RandomPickForRead().URL
+			server = lookup.VolumeLocations.RandomPickForRead().PublicURL
 		} else {
 			server = lookup.VolumeLocations.Head().URL
 		}
@@ -295,30 +295,31 @@ func (c *Seaweed) SubmitFilePart(f *FilePart, args url.Values) (result *SubmitRe
 }
 
 // Upload file by reader.
-func (c *Seaweed) Upload(fileReader io.Reader, fileName string, size int64, collection, ttl string) (fp *FilePart, fileID string, err error) {
+func (c *Seaweed) Upload(fileReader io.Reader, fileName string, size int64, collection, ttl string) (fp *FilePart, err error) {
 	fp = NewFilePartFromReader(ioutil.NopCloser(fileReader), fileName, size)
 	fp.Collection, fp.TTL = collection, ttl
-	_, fileID, err = c.UploadFilePart(fp)
+	_, err = c.UploadFilePart(fp)
 	return
 }
 
 // UploadFile with full file dir/path.
-func (c *Seaweed) UploadFile(filePath string, collection, ttl string) (cm *ChunkManifest, fp *FilePart, fileID string, err error) {
+func (c *Seaweed) UploadFile(filePath string, collection, ttl string) (cm *ChunkManifest, fp *FilePart, err error) {
 	fp, err = NewFilePart(filePath)
 	if err == nil {
 		fp.Collection, fp.TTL = collection, ttl
-		cm, fileID, err = c.UploadFilePart(fp)
+		cm, err = c.UploadFilePart(fp)
 		_ = fp.Close()
 	}
 	return
 }
 
 // UploadFilePart uploads a file part.
-func (c *Seaweed) UploadFilePart(f *FilePart) (cm *ChunkManifest, fileID string, err error) {
+func (c *Seaweed) UploadFilePart(f *FilePart) (cm *ChunkManifest, err error) {
 	if f.FileID == "" {
-		res, err := c.Assign(normalize(nil, f.Collection, f.TTL))
+		var res *AssignResult
+		res, err = c.Assign(normalize(nil, f.Collection, f.TTL))
 		if err != nil {
-			return nil, "", err
+			return
 		}
 		f.Server, f.FileID = res.URL, res.FileID
 	}
@@ -345,7 +346,7 @@ func (c *Seaweed) UploadFilePart(f *FilePart) (cm *ChunkManifest, fileID string,
 			_, id, count, e := c.uploadChunk(f, baseName+"_"+strconv.FormatInt(i+1, 10))
 			if e != nil { // delete all uploaded chunks
 				_ = c.DeleteChunks(cm, normalize(nil, f.Collection, ""))
-				return nil, "", e
+				return nil, e
 			}
 
 			cm.Chunks[i] = &ChunkInfo{
@@ -360,16 +361,14 @@ func (c *Seaweed) UploadFilePart(f *FilePart) (cm *ChunkManifest, fileID string,
 		}
 	} else {
 		args := normalize(nil, f.Collection, f.TTL)
-		args.Set("Content-Type", "multipart/form-data")
 		if f.ModTime != 0 {
 			args.Set("ts", strconv.FormatInt(f.ModTime, 10))
 		}
 
-		_, _, err = c.client.upload(encodeURI(*c.master, f.FileID, args), baseName, f.Reader, f.MimeType)
-	}
+		base := *c.master
+		base.Host = f.Server
 
-	if err == nil {
-		fileID = f.FileID
+		_, _, err = c.client.upload(encodeURI(base, f.FileID, args), baseName, f.Reader, f.MimeType)
 	}
 
 	return
@@ -433,8 +432,7 @@ func (c *Seaweed) BatchUploadFileParts(files []*FilePart, collection string, ttl
 
 func (c *Seaweed) uploadTask(file *FilePart) *workerpool.Task {
 	return workerpool.NewTask(context.Background(), func(ctx context.Context) (res interface{}, err error) {
-		fmt.Println("Uploading", file)
-		_, _, err = c.UploadFilePart(file)
+		_, err = c.UploadFilePart(file)
 		return
 	})
 }
@@ -444,7 +442,7 @@ func (c *Seaweed) Replace(fileID string, newContent io.Reader, fileName string,
 	fp := NewFilePartFromReader(ioutil.NopCloser(newContent), fileName, size)
 	fp.Collection, fp.TTL = collection, ttl
 	fp.FileID = fileID
-	_, err = c.ReplaceFilePart(fp, deleteFirst)
+	err = c.ReplaceFilePart(fp, deleteFirst)
 	return
 }
 
@@ -453,19 +451,19 @@ func (c *Seaweed) ReplaceFile(fileID, localFilePath string, deleteFirst bool) (e
 	fp, err := NewFilePart(localFilePath)
 	if err == nil {
 		fp.FileID = fileID
-		_, err = c.ReplaceFilePart(fp, deleteFirst)
+		err = c.ReplaceFilePart(fp, deleteFirst)
 		_ = fp.Close()
 	}
 	return
 }
 
 // ReplaceFilePart replaces file part.
-func (c *Seaweed) ReplaceFilePart(f *FilePart, deleteFirst bool) (fileID string, err error) {
+func (c *Seaweed) ReplaceFilePart(f *FilePart, deleteFirst bool) (err error) {
 	if deleteFirst && f.FileID != "" {
 		_ = c.DeleteFile(f.FileID, nil)
 	}
 
-	_, fileID, err = c.UploadFilePart(f)
+	_, err = c.UploadFilePart(f)
 	return
 }
 
@@ -507,7 +505,10 @@ func (c *Seaweed) uploadManifest(f *FilePart, manifest *ChunkManifest) (err erro
 		}
 		args.Set("cm", "true")
 
-		_, _, err = c.client.upload(encodeURI(*c.master, f.FileID, args), manifest.Name, bufReader, "application/json")
+		base := *c.master
+		base.Host = f.Server
+
+		_, _, err = c.client.upload(encodeURI(base, f.FileID, args), manifest.Name, bufReader, "application/json")
 	}
 	return
 }
diff --git a/seaweed_test.go b/seaweed_test.go
index 69316fa..23ca36b 100644
--- a/seaweed_test.go
+++ b/seaweed_test.go
@@ -39,10 +39,10 @@ func init() {
 		filer = []string{_filer}
 	}
 
-	sw, _ = NewSeaweed(masterURL, filer, 2*1024*1024, &http.Client{Timeout: 5 * time.Minute})
+	sw, _ = NewSeaweed(masterURL, filer, 8096, &http.Client{Timeout: 5 * time.Minute})
 	_ = sw.Close()
 
-	sw, _ = NewSeaweed(masterURL, filer, 2*1024*1024, &http.Client{Timeout: 5 * time.Minute})
+	sw, _ = NewSeaweed(masterURL, filer, 8096, &http.Client{Timeout: 5 * time.Minute})
 
 	MediumFile = os.Getenv("GOSWFS_MEDIUM_FILE")
 	SmallFile = os.Getenv("GOSWFS_SMALL_FILE")
@@ -50,63 +50,79 @@ func init() {
 
 func TestUploadLookupserverReplaceDeleteFile(t *testing.T) {
 	for i := 0; i < 2; i++ {
-		_, _, fID, err := sw.UploadFile(MediumFile, "", "")
+		_, fp, err := sw.UploadFile(MediumFile, "", "")
 		require.Nil(t, err)
 
-		_, err = sw.LookupServerByFileID(fID, nil, true)
+		_, err = sw.LookupServerByFileID(fp.FileID, nil, true)
 		require.Nil(t, err)
 
-		//
-		_, err = sw.LookupFileID(fID, nil, true)
+		// verify by downloading
+		downloaded := verifyDownloadFile(t, fp.FileID)
+		fh, err := os.Open(MediumFile)
+		require.Nil(t, err)
+		allContent, _ := ioutil.ReadAll(fh)
+		require.Nil(t, fh.Close())
+		require.EqualValues(t, downloaded, allContent)
+
+		// try to looking up
+		_, err = sw.LookupFileID(fp.FileID, nil, true)
 		require.Nil(t, err)
 
-		//
-		require.Nil(t, sw.ReplaceFile(fID, SmallFile, false))
-		_, err = sw.LookupFileID(fID, nil, true)
+		// try to replace with small file
+		require.Nil(t, sw.ReplaceFile(fp.FileID, SmallFile, false))
+		_, err = sw.LookupFileID(fp.FileID, nil, true)
 		require.Nil(t, err)
 
-		//
-		require.Nil(t, sw.ReplaceFile(fID, SmallFile, true))
-		_, err = sw.LookupFileID(fID, nil, true)
+		// verify by downloading
+		downloaded = verifyDownloadFile(t, fp.FileID)
+		fh, err = os.Open(SmallFile)
 		require.Nil(t, err)
+		allContent, _ = ioutil.ReadAll(fh)
+		require.Nil(t, fh.Close())
+		require.EqualValues(t, downloaded, allContent)
 
-		//
-		require.Nil(t, sw.DeleteFile(fID, nil))
+		// replace again but delete first
+		require.Nil(t, sw.ReplaceFile(fp.FileID, SmallFile, true))
+		_, err = sw.LookupFileID(fp.FileID, nil, true)
+		require.Nil(t, err)
 
-		// test upload file
-		fh, err := os.Open(MediumFile)
+		// verify by downloading
+		downloaded = verifyDownloadFile(t, fp.FileID)
+		fh, err = os.Open(SmallFile)
+		require.Nil(t, err)
+		allContent, _ = ioutil.ReadAll(fh)
+		require.Nil(t, fh.Close())
+		require.EqualValues(t, downloaded, allContent)
+
+		// delete file
+		require.Nil(t, sw.DeleteFile(fp.FileID, nil))
+
+		// uploading with file reader
+		fh, err = os.Open(MediumFile)
 		require.Nil(t, err)
 		var size int64
 		fi, fiErr := fh.Stat()
 		require.Nil(t, fiErr)
 		size = fi.Size()
-		_, fID, err = sw.Upload(fh, "test.txt", size, "col", "")
+		fp, err = sw.Upload(fh, "test.txt", size, "col", "")
 		require.Nil(t, err)
 		require.Nil(t, fh.Close())
 
-		// Replace with small file
+		// Replace with small file reader
 		fs, err := os.Open(SmallFile)
 		require.Nil(t, err)
 		fi, fiErr = fs.Stat()
 		require.Nil(t, fiErr)
 		size = fi.Size()
-		require.Nil(t, sw.Replace(fID, fs, "ta.txt", size, "", "", false))
-		require.Nil(t, sw.DeleteFile(fID, nil))
+		require.Nil(t, sw.Replace(fp.FileID, fs, "ta.txt", size, "", "", false))
+		require.Nil(t, sw.DeleteFile(fp.FileID, nil))
 		fs.Close()
 	}
 }
 
 func TestBatchUploadFiles(t *testing.T) {
-	if MediumFile != "" && SmallFile != "" {
-		_, err := sw.BatchUploadFiles([]string{MediumFile, SmallFile}, "", "")
-		require.Nil(t, err)
-	} else if MediumFile != "" {
-		_, err := sw.BatchUploadFiles([]string{MediumFile, MediumFile}, "", "")
-		require.Nil(t, err)
-	} else if SmallFile != "" {
-		_, err := sw.BatchUploadFiles([]string{SmallFile, SmallFile}, "", "")
-		require.Nil(t, err)
-	}
+	_, err := sw.BatchUploadFiles([]string{MediumFile, SmallFile}, "", "")
+	require.Nil(t, err)
 }
 
 func TestLookup(t *testing.T) {
@@ -129,25 +145,34 @@ func TestClusterStatus(t *testing.T) {
 	require.Nil(t, err)
 }
 
-func TestSubmit(t *testing.T) {
-	if SmallFile != "" {
-		_, err := sw.Submit(SmallFile, "", "")
-		require.Nil(t, err)
-	}
+func TestDownloadFile(t *testing.T) {
+	result, err := sw.Submit(SmallFile, "", "")
+	require.Nil(t, err)
+	require.NotNil(t, result)
+
+	// return fake error
+	_, err = sw.Download(result.FileID, nil, func(r io.Reader) error {
+		return fmt.Errorf("Fake error")
+	})
+	require.NotNil(t, err)
+
+	// verifying
+	verifyDownloadFile(t, result.FileID)
 }
 
-func TestDownloadFile(t *testing.T) {
-	if SmallFile != "" {
-		_, err := sw.Download(SmallFile, nil, func(r io.Reader) error {
-			return fmt.Errorf("Fake error")
-		})
-		require.NotNil(t, err)
-	}
+func verifyDownloadFile(t *testing.T, fid string) (data []byte) {
+	_, err := sw.Download(fid, nil, func(r io.Reader) (err error) {
+		data, err = ioutil.ReadAll(r)
+		return
+	})
+	require.Nil(t, err)
+	require.NotZero(t, len(data))
+	return
 }
 
 func TestDeleteChunks(t *testing.T) {
 	if MediumFile != "" {
-		cm, _, _, err := sw.UploadFile(MediumFile, "", "")
+		cm, _, err := sw.UploadFile(MediumFile, "", "")
 		require.Nil(t, err)
 
 		err = sw.DeleteChunks(cm, nil)
@@ -171,7 +196,6 @@ func TestFiler(t *testing.T) {
 	})
 	require.Nil(t, err)
 	require.NotZero(t, buf.Len())
-	t.Log(string(buf.Bytes()))
 
 	// try to delete this file
 	err = filer.Delete("/js/test.txt", nil)