v1.0.0 beta 9

utils/multipart.go

@@ -1,7 +1,6 @@
 package utils
 
 import (
-	"encoding/json"
 	"fmt"
 	"io"
 	"mime/multipart"
@@ -26,33 +25,31 @@ func Encode[T any](w *multipart.Writer, req T) error {
 		field := v.Field(i)
 		fieldType := t.Field(i)
 
-		formTags := strings.Split(fieldType.Tag.Get("json"), ",")
-		fieldName := ""
-		if len(formTags) == 0 {
-			formTags = strings.Split(fieldType.Tag.Get("json"), ",")
+		jsonTag := fieldType.Tag.Get("json")
+		if jsonTag == "" {
+			jsonTag = fieldType.Name
 		}
 
-		if len(formTags) > 0 {
-			fieldName = formTags[0]
-			if fieldName == "-" {
-				continue
-			}
-			if slices.Index(formTags, "omitempty") >= 0 {
-				if field.IsZero() {
-					continue
-				}
-			}
-		} else {
-			fieldName = strings.ToLower(fieldType.Name)
+		parts := strings.Split(jsonTag, ",")
+		fieldName := parts[0]
+		if fieldName == "-" {
+			continue
+		}
+
+		// Handle omitempty
+		isEmpty := field.IsZero()
+		if slices.Contains(parts, "omitempty") && isEmpty {
+			continue
 		}
 
 		var (
 			fw  io.Writer
 			err error
 		)
+
 		switch field.Kind() {
 		case reflect.String:
-			if field.String() != "" {
+			if !isEmpty {
 				fw, err = w.CreateFormField(fieldName)
 				if err == nil {
 					_, err = fw.Write([]byte(field.String()))
@@ -80,45 +77,47 @@ func Encode[T any](w *multipart.Writer, req T) error {
 			}
 		case reflect.Slice:
 			if field.Type().Elem().Kind() == reflect.Uint8 && !field.IsNil() {
+				// Handle []byte as file upload (e.g., thumbnail)
 				filename := fieldType.Tag.Get("filename")
 				if filename == "" {
 					filename = fieldName
 				}
-
-				ext := ""
-				filename = filename + ext
-
 				fw, err = w.CreateFormFile(fieldName, filename)
 				if err == nil {
 					_, err = fw.Write(field.Bytes())
 				}
 			} else if !field.IsNil() {
-				// Handle slice of primitive values (as multiple form fields with the same name)
+				// Handle []string, []int, etc. — send as multiple fields with same name
 				for j := 0; j < field.Len(); j++ {
 					elem := field.Index(j)
 					fw, err = w.CreateFormField(fieldName)
-					if err == nil {
-						switch elem.Kind() {
-						case reflect.String:
-							_, err = fw.Write([]byte(elem.String()))
-						case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
-							_, err = fw.Write([]byte(strconv.FormatInt(elem.Int(), 10)))
-						case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
-							_, err = fw.Write([]byte(strconv.FormatUint(elem.Uint(), 10)))
-						}
+					if err != nil {
+						break
+					}
+					switch elem.Kind() {
+					case reflect.String:
+						_, err = fw.Write([]byte(elem.String()))
+					case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+						_, err = fw.Write([]byte(strconv.FormatInt(elem.Int(), 10)))
+					case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+						_, err = fw.Write([]byte(strconv.FormatUint(elem.Uint(), 10)))
+					case reflect.Bool:
+						_, err = fw.Write([]byte(strconv.FormatBool(elem.Bool())))
+					case reflect.Float32, reflect.Float64:
+						_, err = fw.Write([]byte(strconv.FormatFloat(elem.Float(), 'f', -1, 64)))
+					}
+					if err != nil {
+						break
 					}
 				}
 			}
 
 		case reflect.Struct:
-			var jsonData []byte
-			jsonData, err = json.Marshal(field.Interface())
-			if err == nil {
-				fw, err = w.CreateFormField(fieldName)
-				if err == nil {
-					_, err = fw.Write(jsonData)
-				}
-			}
+			// Don't serialize structs as JSON — flatten them!
+			// Telegram doesn't support nested JSON in form-data.
+			// If you need nested data, use separate fields (e.g., ParseMode, CaptionEntities)
+			// This is a design choice — you should avoid nested structs in params.
+			return fmt.Errorf("nested structs are not supported in params — use flat fields")
 		}
 
 		if err != nil {