Add batch SetMultipartFields in order to set multiple fields (go-res…

…ty#211)

* Add batch SetMultipartFields in order to set multiple fields
* Improve test and update example with comment
* change SetMultipartFields to variadic
* fix usage example comment for SetMultipartFields
* Remove empty new lines for code consistency

client.go

@@ -311,7 +311,7 @@ func (c *Client) R() *Request {
 
 		client:          c,
 		multipartFiles:  []*File{},
-		multipartFields: []*multipartField{},
+		multipartFields: []*MultipartField{},
 		pathParams:      map[string]string{},
 		jsonEscapeHTML:  true,
 	}
@@ -917,8 +917,8 @@ func (f *File) String() string {
 	return fmt.Sprintf("ParamName: %v; FileName: %v", f.ParamName, f.Name)
 }
 
-// multipartField represent custom data part for multipart request
-type multipartField struct {
+// MultipartField represent custom data part for multipart request
+type MultipartField struct {
 	Param       string
 	FileName    string
 	ContentType string

request.go

@@ -244,7 +244,6 @@ func (r *Request) SetError(err interface{}) *Request {
 func (r *Request) SetFile(param, filePath string) *Request {
 	r.isMultiPart = true
 	r.FormData.Set("@"+param, filePath)
-
 	return r
 }
 
@@ -273,27 +272,47 @@ func (r *Request) SetFiles(files map[string]string) *Request {
 //
 func (r *Request) SetFileReader(param, fileName string, reader io.Reader) *Request {
 	r.isMultiPart = true
-
 	r.multipartFiles = append(r.multipartFiles, &File{
 		Name:      fileName,
 		ParamName: param,
 		Reader:    reader,
 	})
-
 	return r
 }
 
 // SetMultipartField method is to set custom data using io.Reader for multipart upload.
 func (r *Request) SetMultipartField(param, fileName, contentType string, reader io.Reader) *Request {
 	r.isMultiPart = true
-
-	r.multipartFields = append(r.multipartFields, &multipartField{
+	r.multipartFields = append(r.multipartFields, &MultipartField{
 		Param:       param,
 		FileName:    fileName,
 		ContentType: contentType,
 		Reader:      reader,
 	})
+	return r
+}
 
+// SetMultipartFields method is to set multiple data fields using io.Reader for multipart upload.
+// Example:
+// 	resty.R().SetMultipartFields(
+// 		&resty.MultipartField{
+//			Param:       "uploadManifest1",
+//			FileName:    "upload-file-1.json",
+//			ContentType: "application/json",
+//			Reader:      strings.NewReader(`{"input": {"name": "Uploaded document 1", "_filename" : ["file1.txt"]}}`),
+//		},
+//		&resty.MultipartField{
+//			Param:       "uploadManifest2",
+//			FileName:    "upload-file-2.json",
+//			ContentType: "application/json",
+//			Reader:      strings.NewReader(`{"input": {"name": "Uploaded document 2", "_filename" : ["file2.txt"]}}`),
+//		})
+//
+// If you have slice already, then simply call-
+// 	resty.R().SetMultipartFields(fields...)
+func (r *Request) SetMultipartFields(fields ...*MultipartField) *Request {
+	r.isMultiPart = true
+	r.multipartFields = append(r.multipartFields, fields...)
 	return r
 }
 
@@ -304,7 +323,6 @@ func (r *Request) SetMultipartField(param, fileName, contentType string, reader
 //
 func (r *Request) SetContentLength(l bool) *Request {
 	r.setContentLength = true
-
 	return r
 }
 

request16.go

@@ -47,7 +47,7 @@ type Request struct {
 	client              *Client
 	bodyBuf             *bytes.Buffer
 	multipartFiles      []*File
-	multipartFields     []*multipartField
+	multipartFields     []*MultipartField
 }
 
 func (r *Request) addContextIfAvailable() {

request17.go

@@ -49,7 +49,7 @@ type Request struct {
 	client              *Client
 	bodyBuf             *bytes.Buffer
 	multipartFiles      []*File
-	multipartFields     []*multipartField
+	multipartFields     []*MultipartField
 }
 
 // Context method returns the Context if its already set in request

request_test.go

@@ -685,6 +685,42 @@ func TestMultiPartMultipartField(t *testing.T) {
 	assertEqual(t, true, strings.Contains(responseStr, "upload-file.json"))
 }
 
+func TestMultiPartMultipartFields(t *testing.T) {
+	ts := createFormPostServer(t)
+	defer ts.Close()
+	defer cleanupFiles(".testdata/upload")
+
+	jsonStr1 := `{"input": {"name": "Uploaded document 1", "_filename" : ["file1.txt"]}}`
+	jsonStr2 := `{"input": {"name": "Uploaded document 2", "_filename" : ["file2.txt"]}}`
+
+	fields := []*MultipartField{
+		&MultipartField{
+			Param:       "uploadManifest1",
+			FileName:    "upload-file-1.json",
+			ContentType: "application/json",
+			Reader:      strings.NewReader(jsonStr1),
+		},
+		&MultipartField{
+			Param:       "uploadManifest2",
+			FileName:    "upload-file-2.json",
+			ContentType: "application/json",
+			Reader:      strings.NewReader(jsonStr2),
+		},
+	}
+
+	resp, err := dclr().
+		SetFormData(map[string]string{"first_name": "Jeevanandam", "last_name": "M"}).
+		SetMultipartFields(fields...).
+		Post(ts.URL + "/upload")
+
+	responseStr := resp.String()
+
+	assertError(t, err)
+	assertEqual(t, http.StatusOK, resp.StatusCode())
+	assertEqual(t, true, strings.Contains(responseStr, "upload-file-1.json"))
+	assertEqual(t, true, strings.Contains(responseStr, "upload-file-2.json"))
+}
+
 func TestGetWithCookie(t *testing.T) {
 	ts := createGetServer(t)
 	defer ts.Close()

util.go

@@ -145,7 +145,7 @@ func createMultipartHeader(param, fileName, contentType string) textproto.MIMEHe
 	return hdr
 }
 
-func addMultipartFormField(w *multipart.Writer, mf *multipartField) error {
+func addMultipartFormField(w *multipart.Writer, mf *MultipartField) error {
 	partWriter, err := w.CreatePart(createMultipartHeader(mf.Param, mf.FileName, mf.ContentType))
 	if err != nil {
 		return err